PERLDIAG(1) Perl Programmers Reference Guide PERLDIAG(1)

PERLDIAG(1) Perl Programmers Reference Guide PERLDIAG(1) #

PERLDIAG(1) Perl Programmers Reference Guide PERLDIAG(1)

NNAAMMEE #

 perldiag - various Perl diagnostics

DDEESSCCRRIIPPTTIIOONN #

 These messages are classified as follows (listed in increasing order of
 desperation):

     (W) A warning (optional).
     (D) A deprecation (enabled by default).
     (S) A severe warning (enabled by default).
     (F) A fatal error (trappable).
     (P) An internal error you should never see (trappable).
     (X) A very fatal error (nontrappable).
     (A) An alien error message (not generated by Perl).

 The majority of messages from the first three classifications above (W, D
 & S) can be controlled using the "warnings" pragma.

 If a message can be controlled by the "warnings" pragma, its warning
 category is included with the classification letter in the description
 below.  E.g. "(W closed)" means a warning in the "closed" category.

 Optional warnings are enabled by using the "warnings" pragma or the --ww
 and --WW switches.  Warnings may be captured by setting $SIG{__WARN__} to a
 reference to a routine that will be called on each warning instead of
 printing it.  See perlvar.

 Severe warnings are always enabled, unless they are explicitly disabled
 with the "warnings" pragma or the --XX switch.

 Trappable errors may be trapped using the eval operator.  See "eval" in
 perlfunc.  In almost all cases, warnings may be selectively disabled or
 promoted to fatal errors using the "warnings" pragma.  See warnings.

 The messages are in alphabetical order, without regard to upper or lower-
 case.  Some of these messages are generic.  Spots that vary are denoted
 with a %s or other printf-style escape.  These escapes are ignored by the
 alphabetical order, as are all characters other than letters.  To look up
 your message, just ignore anything that is not a letter.

 aacccceepptt(()) on closed socket %s
     (W closed) You tried to do an accept on a closed socket.  Did you
     forget to check the return value of your ssoocckkeett(()) call?  See "accept"
     in perlfunc.

 Aliasing via reference is experimental
     (S experimental::refaliasing) This warning is emitted if you use a
     reference constructor on the left-hand side of an assignment to alias
     one variable to another.  Simply suppress the warning if you want to
     use the feature, but know that in doing so you are taking the risk of
     using an experimental feature which may change or be removed in a
     future Perl version:

         no warnings "experimental::refaliasing";
         use feature "refaliasing";
         \$x = \$y;

 '%c' allowed only after types %s in %s
     (F) The modifiers '!', '<' and '>' are allowed in ppaacckk(()) or uunnppaacckk(())
     only after certain types.  See "pack" in perlfunc.

 alpha->nnuummiiffyy(()) is lossy
     (W numeric) An alpha version can not be numified without losing
     information.

 Ambiguous call resolved as CORE::%s(), qualify as such or use &
     (W ambiguous) A subroutine you have declared has the same name as a
     Perl keyword, and you have used the name without qualification for
     calling one or the other.  Perl decided to call the builtin because
     the subroutine is not imported.

     To force interpretation as a subroutine call, either put an ampersand
     before the subroutine name, or qualify the name with its package.
     Alternatively, you can import the subroutine (or pretend that it's
     imported with the "use subs" pragma).

     To silently interpret it as the Perl operator, use the "CORE::"
     prefix on the operator (e.g. "CORE::log($x)") or declare the
     subroutine to be an object method (see "Subroutine Attributes" in
     perlsub or attributes).

 Ambiguous range in transliteration operator
     (F) You wrote something like "tr/a-z-0//" which doesn't mean anything
     at all.  To include a "-" character in a transliteration, put it
     either first or last.  (In the past, "tr/a-z-0//" was synonymous with
     "tr/a-y//", which was probably not what you would have expected.)

 Ambiguous use of %s resolved as %s
     (S ambiguous) You said something that may not be interpreted the way
     you thought.  Normally it's pretty easy to disambiguate it by
     supplying a missing quote, operator, parenthesis pair or declaration.

 Ambiguous use of -%s resolved as -&%s()
     (S ambiguous) You wrote something like "-foo", which might be the
     string "-foo", or a call to the function "foo", negated.  If you
     meant the string, just write "-foo".  If you meant the function call,
     write "-foo()".

 Ambiguous use of %c resolved as operator %c
     (S ambiguous) "%", "&", and "*" are both infix operators (modulus,
     bitwise and, and multiplication) _a_n_d initial special characters
     (denoting hashes, subroutines and typeglobs), and you said something
     like "*foo * foo" that might be interpreted as either of them.  We
     assumed you meant the infix operator, but please try to make it more
     clear -- in the example given, you might write "*foo * foo()" if you
     really meant to multiply a glob by the result of calling a function.

 Ambiguous use of %c{%s} resolved to %c%s
     (W ambiguous) You wrote something like "@{foo}", which might be
     asking for the variable @foo, or it might be calling a function named
     foo, and dereferencing it as an array reference.  If you wanted the
     variable, you can just write @foo.  If you wanted to call the
     function, write "@{foo()}" ... or you could just not have a variable
     and a function with the same name, and save yourself a lot of
     trouble.

 Ambiguous use of %c{%s[...]} resolved to %c%s[...]
 Ambiguous use of %c{%s{...}} resolved to %c%s{...}
     (W ambiguous) You wrote something like "${foo[2]}" (where foo
     represents the name of a Perl keyword), which might be looking for
     element number 2 of the array named @foo, in which case please write
     $foo[2], or you might have meant to pass an anonymous arrayref to the
     function named foo, and then do a scalar deref on the value it
     returns.  If you meant that, write "${foo([2])}".

     In regular expressions, the "${foo[2]}" syntax is sometimes necessary
     to disambiguate between array subscripts and character classes.
     "/$length[2345]/", for instance, will be interpreted as $length
     followed by the character class "[2345]".  If an array subscript is
     what you want, you can avoid the warning by changing
     "/${length[2345]}/" to the unsightly "/${\$length[2345]}/", by
     renaming your array to something that does not coincide with a built-
     in keyword, or by simply turning off warnings with "no warnings
     'ambiguous';".

 '|' and '<' may not both be specified on command line
     (F) An error peculiar to VMS.  Perl does its own command line
     redirection, and found that STDIN was a pipe, and that you also tried
     to redirect STDIN using '<'.  Only one STDIN stream to a customer,
     please.

 '|' and '>' may not both be specified on command line
     (F) An error peculiar to VMS.  Perl does its own command line
     redirection, and thinks you tried to redirect stdout both to a file
     and into a pipe to another command.  You need to choose one or the
     other, though nothing's stopping you from piping into a program or
     Perl script which 'splits' output into two streams, such as

         open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
         while (<STDIN>) {
             print;
             print OUT;
         }
         close OUT;

 Applying %s to %s will act on scalar(%s)
     (W misc) The pattern match ("//"), substitution ("s///"), and
     transliteration ("tr///") operators work on scalar values.  If you
     apply one of them to an array or a hash, it will convert the array or
     hash to a scalar value (the length of an array, or the population
     info of a hash) and then work on that scalar value.  This is probably
     not what you meant to do.  See "grep" in perlfunc and "map" in
     perlfunc for alternatives.

 Arg too short for msgsnd
     (F) mmssggssnndd(()) requires a string at least as long as sizeof(long).

 Argument "%s" isn't numeric%s
     (W numeric) The indicated string was fed as an argument to an
     operator that expected a numeric value instead.  If you're fortunate
     the message will identify which operator was so unfortunate.

     Note that for the "Inf" and "NaN" (infinity and not-a-number) the
     definition of "numeric" is somewhat unusual: the strings themselves
     (like "Inf") are considered numeric, and anything following them is
     considered non-numeric.

 Argument list not closed for PerlIO layer "%s"
     (W layer) When pushing a layer with arguments onto the Perl I/O
     system you forgot the ) that closes the argument list.  (Layers take
     care of transforming data between external and internal
     representations.)  Perl stopped parsing the layer list at this point
     and did not attempt to push this layer.  If your program didn't
     explicitly request the failing operation, it may be the result of the
     value of the environment variable PERLIO.

 Argument "%s" treated as 0 in increment (++)
     (W numeric) The indicated string was fed as an argument to the "++"
     operator which expects either a number or a string matching
     "/^[a-zA-Z]*[0-9]*\z/".  See "Auto-increment and Auto-decrement" in
     perlop for details.

 Array passed to stat will be coerced to a scalar%s
     (W syntax) You called ssttaatt(()) on an array, but the array will be
     coerced to a scalar - the number of elements in the array.

 A signature parameter must start with '$', '@' or '%'
     (F) Each subroutine signature parameter declaration must start with a
     valid sigil; for example:

         sub foo ($a, $, $b = 1, @c) {}

 A slurpy parameter may not have a default value
     (F) Only scalar subroutine signature parameters may have a default
     value; for example:

         sub foo ($a = 1)        {} # legal
         sub foo (@a = (1))      {} # invalid
         sub foo (%a = (a => b)) {} # invalid

 assertion botched: %s
     (X) The malloc package that comes with Perl had an internal failure.

 Assertion %s failed: file "%s", line %d
     (X) A general assertion failed.  The file in question must be
     examined.

 Assigned value is not a reference
     (F) You tried to assign something that was not a reference to an
     lvalue reference (e.g., "\$x = $y").  If you meant to make $x an
     alias to $y, use "\$x = \$y".

 Assigned value is not %s reference
     (F) You tried to assign a reference to a reference constructor, but
     the two references were not of the same type.  You cannot alias a
     scalar to an array, or an array to a hash; the two types must match.

         \$x = \@y;  # error
         \@x = \%y;  # error
          $y = [];
         \$x = $y;   # error; did you mean \$y?

 Assigning non-zero to $[ is no longer possible
     (F) When the "array_base" feature is disabled (e.g., and under "use
     v5.16;", and as of Perl 5.30) the special variable $[, which is
     deprecated, is now a fixed zero value.

 Assignment to both a list and a scalar
     (F) If you assign to a conditional operator, the 2nd and 3rd
     arguments must either both be scalars or both be lists.  Otherwise
     Perl won't know which context to supply to the right side.

 Assuming NOT a POSIX class since %s in regex; marked by <-- HERE in m/%s/
     (W regexp) You had something like these:

      [[:alnum]]
      [[:digit:xyz]

     They look like they might have been meant to be the POSIX classes
     "[:alnum:]" or "[:digit:]".  If so, they should be written:

      [[:alnum:]]
      [[:digit:]xyz]

     Since these aren't legal POSIX class specifications, but are legal
     bracketed character classes, Perl treats them as the latter.  In the
     first example, it matches the characters ":", "[", "a", "l", "m",
     "n", and "u".

     If these weren't meant to be POSIX classes, this warning message is
     spurious, and can be suppressed by reordering things, such as

      [[al:num]]

     or

      [[:munla]]

 <> at require-statement should be quotes
     (F) You wrote "require <file>" when you should have written "require
     'file'".

 Attempt to access disallowed key '%s' in a restricted hash
     (F) The failing code has attempted to get or set a key which is not
     in the current set of allowed keys of a restricted hash.

 Attempt to bless into a freed package
     (F) You wrote "bless $foo" with one argument after somehow causing
     the current package to be freed.  Perl cannot figure out what to do,
     so it throws up its hands in despair.

 Attempt to bless into a reference
     (F) The CLASSNAME argument to the bblleessss(()) operator is expected to be
     the name of the package to bless the resulting object into.  You've
     supplied instead a reference to something: perhaps you wrote

         bless $self, $proto;

     when you intended

         bless $self, ref($proto) || $proto;

     If you actually want to bless into the stringified version of the
     reference supplied, you need to stringify it yourself, for example
     by:

         bless $self, "$proto";

 Attempt to clear deleted array
     (S debugging) An array was assigned to when it was being freed.
     Freed values are not supposed to be visible to Perl code.  This can
     also happen if XS code calls "av_clear" from a custom magic callback
     on the array.

 Attempt to delete disallowed key '%s' from a restricted hash
     (F) The failing code attempted to delete from a restricted hash a key
     which is not in its key set.

 Attempt to delete readonly key '%s' from a restricted hash
     (F) The failing code attempted to delete a key whose value has been
     declared readonly from a restricted hash.

 Attempt to free non-arena SV: 0x%x
     (S internal) All SV objects are supposed to be allocated from arenas
     that will be garbage collected on exit.  An SV was discovered to be
     outside any of those arenas.

 Attempt to free nonexistent shared string '%s'%s
     (S internal) Perl maintains a reference-counted internal table of
     strings to optimize the storage and access of hash keys and other
     strings.  This indicates someone tried to decrement the reference
     count of a string that can no longer be found in the table.

 Attempt to free temp prematurely: SV 0x%x
     (S debugging) Mortalized values are supposed to be freed by the
     ffrreeee__ttmmppss(()) routine.  This indicates that something else is freeing
     the SV before the ffrreeee__ttmmppss(()) routine gets a chance, which means that
     the ffrreeee__ttmmppss(()) routine will be freeing an unreferenced scalar when
     it does try to free it.

 Attempt to free unreferenced glob pointers
     (S internal) The reference counts got screwed up on symbol aliases.

 Attempt to free unreferenced scalar: SV 0x%x
     (S internal) Perl went to decrement the reference count of a scalar
     to see if it would go to 0, and discovered that it had already gone
     to 0 earlier, and should have been freed, and in fact, probably was
     freed.  This could indicate that SSvvRREEFFCCNNTT__ddeecc(()) was called too many
     times, or that SSvvRREEFFCCNNTT__iinncc(()) was called too few times, or that the
     SV was mortalized when it shouldn't have been, or that memory has
     been corrupted.

 Attempt to pack pointer to temporary value
     (W pack) You tried to pass a temporary value (like the result of a
     function, or a computed expression) to the "p" ppaacckk(()) template.  This
     means the result contains a pointer to a location that could become
     invalid anytime, even before the end of the current statement.  Use
     literals or global values as arguments to the "p" ppaacckk(()) template to
     avoid this warning.

 Attempt to reload %s aborted.
     (F) You tried to load a file with "use" or "require" that failed to
     compile once already.  Perl will not try to compile this file again
     unless you delete its entry from %INC.  See "require" in perlfunc and
     "%INC" in perlvar.

 Attempt to set length of freed array
     (W misc) You tried to set the length of an array which has been
     freed.  You can do this by storing a reference to the scalar
     representing the last index of an array and later assigning through
     that reference.  For example

         $r = do {my @a; \$#a};
         $$r = 503

 Attempt to use reference as lvalue in substr
     (W substr) You supplied a reference as the first argument to ssuubbssttrr(())
     used as an lvalue, which is pretty strange.  Perhaps you forgot to
     dereference it first.  See "substr" in perlfunc.

 Attribute prototype(%s) discards earlier prototype attribute in same sub
     (W misc) A sub was declared as sub foo : prototype(A) : prototype(B)
     {}, for example.  Since each sub can only have one prototype, the
     earlier declaration(s) are discarded while the last one is applied.

 av_reify called on tied array
     (S debugging) This indicates that something went wrong and Perl got
     _v_e_r_y confused about @_ or @DB::args being tied.

 Bad arg length for %s, is %u, should be %d
     (F) You passed a buffer of the wrong size to one of mmssggccttll(()),
     sseemmccttll(()) or sshhmmccttll(()).  In C parlance, the correct sizes are,
     respectively, sizeof(struct msqid_ds *), sizeof(struct semid_ds *),
     and sizeof(struct shmid_ds *).

 Bad evalled substitution pattern
     (F) You've used the "/e" switch to evaluate the replacement for a
     substitution, but perl found a syntax error in the code to evaluate,
     most likely an unexpected right brace '}'.

 Bad filehandle: %s
     (F) A symbol was passed to something wanting a filehandle, but the
     symbol has no filehandle associated with it.  Perhaps you didn't do
     an ooppeenn(()), or did it in another package.

 Bad ffrreeee(()) ignored
     (S malloc) An internal routine called ffrreeee(()) on something that had
     never been mmaalllloocc(())ed in the first place.  Mandatory, but can be
     disabled by setting environment variable "PERL_BADFREE" to 0.

     This message can be seen quite often with DB_File on systems with
     "hard" dynamic linking, like "AIX" and "OS/2".  It is a bug of
     "Berkeley DB" which is left unnoticed if "DB" uses _f_o_r_g_i_v_i_n_g system
     mmaalllloocc(()).

 Badly placed ()'s
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 Bad name after %s
     (F) You started to name a symbol by using a package prefix, and then
     didn't finish the symbol.  In particular, you can't interpolate
     outside of quotes, so

         $var = 'myvar';
         $sym = mypack::$var;

     is not the same as

         $var = 'myvar';
         $sym = "mypack::$var";

 Bad plugin affecting keyword '%s'
     (F) An extension using the keyword plugin mechanism violated the
     plugin API.

 Bad rreeaalllloocc(()) ignored
     (S malloc) An internal routine called rreeaalllloocc(()) on something that had
     never been mmaalllloocc(())ed in the first place.  Mandatory, but can be
     disabled by setting the environment variable "PERL_BADFREE" to 1.

 Bad symbol for array
     (P) An internal request asked to add an array entry to something that
     wasn't a symbol table entry.

 Bad symbol for dirhandle
     (P) An internal request asked to add a dirhandle entry to something
     that wasn't a symbol table entry.

 Bad symbol for filehandle
     (P) An internal request asked to add a filehandle entry to something
     that wasn't a symbol table entry.

 Bad symbol for hash
     (P) An internal request asked to add a hash entry to something that
     wasn't a symbol table entry.

 Bad symbol for scalar
     (P) An internal request asked to add a scalar entry to something that
     wasn't a symbol table entry.

 Bareword found in conditional
     (W bareword) The compiler found a bareword where it expected a
     conditional, which often indicates that an || or && was parsed as
     part of the last argument of the previous construct, for example:

         open FOO || die;

     It may also indicate a misspelled constant that has been interpreted
     as a bareword:

         use constant TYPO => 1;
         if (TYOP) { print "foo" }

     The "strict" pragma is useful in avoiding such errors.

 Bareword in require contains "%s"
 Bareword in require maps to disallowed filename "%s"
 Bareword in require maps to empty filename
     (F) The bareword form of require has been invoked with a filename
     which could not have been generated by a valid bareword permitted by
     the parser.  You shouldn't be able to get this error from Perl code,
     but XS code may throw it if it passes an invalid module name to
     "Perl_load_module".

 Bareword in require must not start with a double-colon: "%s"
     (F) In "require Bare::Word", the bareword is not allowed to start
     with a double-colon.  Write "require ::Foo::Bar" as  "require
     Foo::Bar" instead.

 Bareword "%s" not allowed while "strict subs" in use
     (F) With "strict subs" in use, a bareword is only allowed as a
     subroutine identifier, in curly brackets or to the left of the "=>"
     symbol.  Perhaps you need to predeclare a subroutine?

 Bareword "%s" refers to nonexistent package
     (W bareword) You used a qualified bareword of the form "Foo::", but
     the compiler saw no other uses of that namespace before that point.
     Perhaps you need to predeclare a package?

 Bareword filehandle "%s" not allowed under 'no feature
 "bareword_filehandles"'
     (F) You attempted to use a bareword filehandle with the
     "bareword_filehandles" feature disabled.

     Only the built-in handles "STDIN", "STDOUT", "STDERR", "ARGV",
     "ARGVOUT" and "DATA" can be used with the "bareword_filehandles"
     feature disabled.

 BEGIN failed--compilation aborted
     (F) An untrapped exception was raised while executing a BEGIN
     subroutine.  Compilation stops immediately and the interpreter is
     exited.

 BEGIN not safe after errors--compilation aborted
     (F) Perl found a "BEGIN {}" subroutine (or a "use" directive, which
     implies a "BEGIN {}") after one or more compilation errors had
     already occurred.  Since the intended environment for the "BEGIN {}"
     could not be guaranteed (due to the errors), and since subsequent
     code likely depends on its correct operation, Perl just gave up.

 \%d better written as $%d
     (W syntax) Outside of patterns, backreferences live on as variables.
     The use of backslashes is grandfathered on the right-hand side of a
     substitution, but stylistically it's better to use the variable form
     because other Perl programmers will expect it, and it works better if
     there are more than 9 backreferences.

 Binary number > 0b11111111111111111111111111111111 non-portable
     (W portable) The binary number you specified is larger than 2**32-1
     (4294967295) and therefore non-portable between systems.  See
     perlport for more on portability concerns.

 bbiinndd(()) on closed socket %s
     (W closed) You tried to do a bind on a closed socket.  Did you forget
     to check the return value of your ssoocckkeett(()) call?  See "bind" in
     perlfunc.

 bbiinnmmooddee(()) on closed filehandle %s
     (W unopened) You tried bbiinnmmooddee(()) on a filehandle that was never
     opened.  Check your control flow and number of arguments.

 Bit vector size > 32 non-portable
     (W portable) Using bit vector sizes larger than 32 is non-portable.

 Bizarre copy of %s
     (P) Perl detected an attempt to copy an internal value that is not
     copiable.

 Bizarre SvTYPE [%d]
     (P) When starting a new thread or returning values from a thread,
     Perl encountered an invalid data type.

 Both or neither range ends should be Unicode in regex; marked by <-- HERE
 in m/%s/
     (W regexp) (only under "use re 'strict'" or within "(?[...])")

     In a bracketed character class in a regular expression pattern, you
     had a range which has exactly one end of it specified using "\N{}",
     and the other end is specified using a non-portable mechanism.  Perl
     treats the range as a Unicode range, that is, all the characters in
     it are considered to be the Unicode characters, and which may be
     different code points on some platforms Perl runs on.  For example,
     "[\N{U+06}-\x08]" is treated as if you had instead said
     "[\N{U+06}-\N{U+08}]", that is it matches the characters whose code
     points in Unicode are 6, 7, and 8.  But that "\x08" might indicate
     that you meant something different, so the warning gets raised.

 Buffer overflow in prime_env_iter: %s
     (W internal) A warning peculiar to VMS.  While Perl was preparing to
     iterate over %ENV, it encountered a logical name or symbol definition
     which was too long, so it was truncated to the string shown.

 Built-in function '%s' is experimental
     (S experimental::builtin) A call is being made to a function in the
     "builtin::" namespace, which is currently experimental. The existence
     or nature of the function may be subject to change in a future
     version of Perl.

 builtin::import can only be called at compile time
     (F) The "import" method of the "builtin" package was invoked when no
     code is currently being compiled. Since this method is used to
     introduce new lexical subroutines into the scope currently being
     compiled, this is not going to have any effect.

 Callback called exit
     (F) A subroutine invoked from an external package via ccaallll__ssvv(())
     exited by calling exit.

 %s() called too early to check prototype
     (W prototype) You've called a function that has a prototype before
     the parser saw a definition or declaration for it, and Perl could not
     check that the call conforms to the prototype.  You need to either
     add an early prototype declaration for the subroutine in question, or
     move the subroutine definition ahead of the call to get proper
     prototype checking.  Alternatively, if you are certain that you're
     calling the function correctly, you may put an ampersand before the
     name to avoid the warning.  See perlsub.

 Cannot chr %f
     (F) You passed an invalid number (like an infinity or not-a-number)
     to "chr".

 Cannot complete in-place edit of %s: %s
     (F) Your perl script appears to have changed directory while
     performing an in-place edit of a file specified by a relative path,
     and your system doesn't include the directory relative POSIX
     functions needed to handle that.

 Cannot compress %f in pack
     (F) You tried compressing an infinity or not-a-number as an unsigned
     integer with BER, which makes no sense.

 Cannot compress integer in pack
     (F) An argument to pack("w",...) was too large to compress.  The BER
     compressed integer format can only be used with positive integers,
     and you attempted to compress a very large number (> 1e308).  See
     "pack" in perlfunc.

 Cannot compress negative numbers in pack
     (F) An argument to pack("w",...) was negative.  The BER compressed
     integer format can only be used with positive integers.  See "pack"
     in perlfunc.

 Cannot convert a reference to %s to typeglob
     (F) You manipulated Perl's symbol table directly, stored a reference
     in it, then tried to access that symbol via conventional Perl syntax.
     The access triggers Perl to autovivify that typeglob, but it there is
     no legal conversion from that type of reference to a typeglob.

 Cannot copy to %s
     (P) Perl detected an attempt to copy a value to an internal type that
     cannot be directly assigned to.

 Cannot find encoding "%s"
     (S io) You tried to apply an encoding that did not exist to a
     filehandle, either with ooppeenn(()) or bbiinnmmooddee(()).

 Cannot open %s as a dirhandle: it is already open as a filehandle
     (F) You tried to use ooppeennddiirr(()) to associate a dirhandle to a symbol
     (glob or scalar) that already holds a filehandle.  Since this idiom
     might render your code confusing, it was deprecated in Perl 5.10.  As
     of Perl 5.28, it is a fatal error.

 Cannot open %s as a filehandle: it is already open as a dirhandle
     (F) You tried to use ooppeenn(()) to associate a filehandle to a symbol
     (glob or scalar) that already holds a dirhandle.  Since this idiom
     might render your code confusing, it was deprecated in Perl 5.10.  As
     of Perl 5.28, it is a fatal error.

 Cannot pack %f with '%c'
     (F) You tried converting an infinity or not-a-number to an integer,
     which makes no sense.

 Cannot printf %f with '%c'
     (F) You tried printing an infinity or not-a-number as a character
     (%c), which makes no sense.  Maybe you meant '%s', or just
     stringifying it?

 Cannot set tied @DB::args
     (F) "caller" tried to set @DB::args, but found it tied.  Tying
     @DB::args is not supported.  (Before this error was added, it used to
     crash.)

 Cannot tie unreifiable array
     (P) You somehow managed to call "tie" on an array that does not keep
     a reference count on its arguments and cannot be made to do so.  Such
     arrays are not even supposed to be accessible to Perl code, but are
     only used internally.

 Cannot yet reorder ssvv__vvccaattppvvffnn(()) arguments from va_list
     (F) Some XS code tried to use "sv_vcatpvfn()" or a related function
     with a format string that specifies explicit indexes for some of the
     elements, and using a C-style variable-argument list (a "va_list").
     This is not currently supported.  XS authors wanting to do this must
     instead construct a C array of "SV*" scalars containing the
     arguments.

 Can only compress unsigned integers in pack
     (F) An argument to pack("w",...) was not an integer.  The BER
     compressed integer format can only be used with positive integers,
     and you attempted to compress something else.  See "pack" in
     perlfunc.

 Can't "%s" out of a "defer" block
     (F) An attempt was made to jump out of the scope of a "defer" block
     by using a control-flow statement such as "return", "goto" or a loop
     control. This is not permitted.

 Can't "%s" out of a "finally" block
     (F) Similar to above, but involving a "finally" block at the end of a
     "try"/"catch" construction rather than a "defer" block.

 Can't bless non-reference value
     (F) Only hard references may be blessed.  This is how Perl "enforces"
     encapsulation of objects.  See perlobj.

 Can't "break" in a loop topicalizer
     (F) You called "break", but you're in a "foreach" block rather than a
     "given" block.  You probably meant to use "next" or "last".

 Can't "break" outside a given block
     (F) You called "break", but you're not inside a "given" block.

 Can't call method "%s" on an undefined value
     (F) You used the syntax of a method call, but the slot filled by the
     object reference or package name contains an undefined value.
     Something like this will reproduce the error:

         $BADREF = undef;
         process $BADREF 1,2,3;
         $BADREF->process(1,2,3);

 Can't call method "%s" on unblessed reference
     (F) A method call must know in what package it's supposed to run.  It
     ordinarily finds this out from the object reference you supply, but
     you didn't supply an object reference in this case.  A reference
     isn't an object reference until it has been blessed.  See perlobj.

 Can't call method "%s" without a package or object reference
     (F) You used the syntax of a method call, but the slot filled by the
     object reference or package name contains an expression that returns
     a defined value which is neither an object reference nor a package
     name.  Something like this will reproduce the error:

$BADREF = 42; #

         process $BADREF 1,2,3;
         $BADREF->process(1,2,3);

 Can't call mmrroo__iissaa__cchhaannggeedd__iinn(()) on anonymous symbol table
     (P) Perl got confused as to whether a hash was a plain hash or a
     symbol table hash when trying to update @ISA caches.

 Can't call mmrroo__mmeetthhoodd__cchhaannggeedd__iinn(()) on anonymous symbol table
     (F) An XS module tried to call "mro_method_changed_in" on a hash that
     was not attached to the symbol table.

 Can't chdir to %s
     (F) You called "perl -x/foo/bar", but _/_f_o_o_/_b_a_r is not a directory
     that you can chdir to, possibly because it doesn't exist.

 Can't coerce %s to %s in %s
     (F) Certain types of SVs, in particular real symbol table entries
     (typeglobs), can't be forced to stop being what they are.  So you
     can't say things like:

         *foo += 1;

     You CAN say

         $foo = *foo;
         $foo += 1;

     but then $foo no longer contains a glob.

 Can't "continue" outside a when block
     (F) You called "continue", but you're not inside a "when" or
     "default" block.

 Can't create pipe mailbox
     (P) An error peculiar to VMS.  The process is suffering from
     exhausted quotas or other plumbing problems.

 Can't declare %s in "%s"
     (F) Only scalar, array, and hash variables may be declared as "my",
     "our" or "state" variables.  They must have ordinary identifiers as
     names.

 Can't "default" outside a topicalizer
     (F) You have used a "default" block that is neither inside a
     "foreach" loop nor a "given" block.  (Note that this error is issued
     on exit from the "default" block, so you won't get the error if you
     use an explicit "continue".)

 Can't determine class of operator %s, assuming BASEOP
     (S) This warning indicates something wrong in the internals of perl.
     Perl was trying to find the class (e.g. LISTOP) of a particular OP,
     and was unable to do so. This is likely to be due to a bug in the
     perl internals, or due to a bug in XS code which manipulates perl
     optrees.

 Can't do inplace edit: %s is not a regular file
     (S inplace) You tried to use the --ii switch on a special file, such as
     a file in /dev, a FIFO or an uneditable directory.  The file was
     ignored.

 Can't do inplace edit on %s: %s
     (S inplace) The creation of the new file failed for the indicated
     reason.

 Can't do inplace edit: %s would not be unique
     (S inplace) Your filesystem does not support filenames longer than 14
     characters and Perl was unable to create a unique filename during
     inplace editing with the --ii switch.  The file was ignored.

 Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
     (W locale) You are 1) running under ""use locale""; 2) the current
     locale is not a UTF-8 one; 3) you tried to do the designated case-
     change operation on the specified Unicode character; and 4) the
     result of this operation would mix Unicode and locale rules, which
     likely conflict.  Mixing of different rule types is forbidden, so the
     operation was not done; instead the result is the indicated value,
     which is the best available that uses entirely Unicode rules.  That
     turns out to almost always be the original character, unchanged.

     It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
     this issue is one of the reasons why.  This warning is raised when
     Unicode rules would normally cause the result of this operation to
     contain a character that is in the range specified by the locale,
     0..255, and hence is subject to the locale's rules, not Unicode's.

     If you are using locale purely for its characteristics related to
     things like its numeric and time formatting (and not "LC_CTYPE"),
     consider using a restricted form of the locale pragma (see "The "use
     locale" pragma" in perllocale) like ""use locale ':not_characters'"".

     Note that failed case-changing operations done as a result of case-
     insensitive "/i" regular expression matching will show up in this
     warning as having the "fc" operation (as that is what the regular
     expression engine calls behind the scenes.)

 Can't do waitpid with flags
     (F) This machine doesn't have either wwaaiittppiidd(()) or wwaaiitt44(()), so only
     wwaaiittppiidd(()) without flags is emulated.

 Can't emulate -%s on #! line
     (F) The #! line specifies a switch that doesn't make sense at this
     point.  For example, it'd be kind of silly to put a --xx on the #!
     line.

 Can't %s %s-endian %ss on this platform
     (F) Your platform's byte-order is neither big-endian nor little-
     endian, or it has a very strange pointer size.  Packing and unpacking
     big- or little-endian floating point values and pointers may not be
     possible.  See "pack" in perlfunc.

 Can't exec "%s": %s
     (W exec) A ssyysstteemm(()), eexxeecc(()), or piped open call could not execute the
     named program for the indicated reason.  Typical reasons include: the
     permissions were wrong on the file, the file wasn't found in
     $ENV{PATH}, the executable in question was compiled for another
     architecture, or the #! line in a script points to an interpreter
     that can't be run for similar reasons.  (Or maybe your system doesn't
     support #! at all.)

 Can't exec %s
     (F) Perl was trying to execute the indicated program for you because
     that's what the #! line said.  If that's not what you wanted, you may
     need to mention "perl" on the #! line somewhere.

 Can't execute %s
     (F) You used the --SS switch, but the copies of the script to execute
     found in the PATH did not have correct permissions.

 Can't find an opnumber for "%s"
     (F) A string of a form "CORE::word" was given to pprroottoottyyppee(()), but
     there is no builtin with the name "word".

 Can't find label %s
     (F) You said to goto a label that isn't mentioned anywhere that it's
     possible for us to go to.  See "goto" in perlfunc.

 Can't find %s on PATH
     (F) You used the --SS switch, but the script to execute could not be
     found in the PATH.

 Can't find %s on PATH, '.' not in PATH
     (F) You used the --SS switch, but the script to execute could not be
     found in the PATH, or at least not with the correct permissions.  The
     script exists in the current directory, but PATH prohibits running
     it.

 Can't find string terminator %s anywhere before EOF
     (F) Perl strings can stretch over multiple lines.  This message means
     that the closing delimiter was omitted.  Because bracketed quotes
     count nesting levels, the following is missing its final parenthesis:

         print q(The character '(' starts a side comment.);

     If you're getting this error from a here-document, you may have
     included unseen whitespace before or after your closing tag or there
     may not be a linebreak after it.  A good programmer's editor will
     have a way to help you find these characters (or lack of characters).
     See perlop for the full details on here-documents.

 Can't find Unicode property definition "%s"
 Can't find Unicode property definition "%s" in regex; marked by <-- HERE
 in m/%s/
     (F) The named property which you specified via "\p" or "\P" is not
     one known to Perl.  Perhaps you misspelled the name?  See "Properties
     accessible through \p{} and \P{}" in perluniprops for a complete list
     of available official properties.  If it is a user-defined property
     it must have been defined by the time the regular expression is
     matched.

     If you didn't mean to use a Unicode property, escape the "\p", either
     by "\\p" (just the "\p") or by "\Q\p" (the rest of the string, or
     until "\E").

 Can't fork: %s
     (F) A fatal error occurred while trying to fork while opening a
     pipeline.

 Can't fork, trying again in 5 seconds
     (W pipe) A fork in a piped open failed with EAGAIN and will be
     retried after five seconds.

 Can't get filespec - stale stat buffer?
     (S) A warning peculiar to VMS.  This arises because of the difference
     between access checks under VMS and under the Unix model Perl
     assumes.  Under VMS, access checks are done by filename, rather than
     by bits in the stat buffer, so that ACLs and other protections can be
     taken into account.  Unfortunately, Perl assumes that the stat buffer
     contains all the necessary information, and passes it, instead of the
     filespec, to the access-checking routine.  It will try to retrieve
     the filespec using the device name and FID present in the stat
     buffer, but this works only if you haven't made a subsequent call to
     the CRTL ssttaatt(()) routine, because the device name is overwritten with
     each call.  If this warning appears, the name lookup failed, and the
     access-checking routine gave up and returned FALSE, just to be
     conservative.  (Note: The access-checking routine knows about the
     Perl "stat" operator and file tests, so you shouldn't ever see this
     warning in response to a Perl command; it arises only if some
     internal code takes stat buffers lightly.)

 Can't get pipe mailbox device name
     (P) An error peculiar to VMS.  After creating a mailbox to act as a
     pipe, Perl can't retrieve its name for later use.

 Can't get SYSGEN parameter value for MAXBUF
     (P) An error peculiar to VMS.  Perl asked $GETSYI how big you want
     your mailbox buffers to be, and didn't get an answer.

 Can't "goto" into a binary or list expression
     (F) A "goto" statement was executed to jump into the middle of a
     binary or list expression.  You can't get there from here.  The
     reason for this restriction is that the interpreter would get
     confused as to how many arguments there are, resulting in stack
     corruption or crashes.  This error occurs in cases such as these:

         goto F;
         print do { F: }; # Can't jump into the arguments to print

         goto G;
         $x + do { G: $y }; # How is + supposed to get its first operand?

 Can't "goto" into a "defer" block
     (F) A "goto" statement was executed to jump into the scope of a
     "defer" block.  This is not permitted.

 Can't "goto" into a "given" block
     (F) A "goto" statement was executed to jump into the middle of a
     "given" block.  You can't get there from here.  See "goto" in
     perlfunc.

 Can't "goto" into the middle of a foreach loop
     (F) A "goto" statement was executed to jump into the middle of a
     foreach loop.  You can't get there from here.  See "goto" in
     perlfunc.

 Can't "goto" out of a pseudo block
     (F) A "goto" statement was executed to jump out of what might look
     like a block, except that it isn't a proper block.  This usually
     occurs if you tried to jump out of a ssoorrtt(()) block or subroutine,
     which is a no-no.  See "goto" in perlfunc.

 Can't goto subroutine from an eval-%s
     (F) The "goto subroutine" call can't be used to jump out of an eval
     "string" or block.

 Can't goto subroutine from a sort sub (or similar callback)
     (F) The "goto subroutine" call can't be used to jump out of the
     comparison sub for a ssoorrtt(()), or from a similar callback (such as the
     rreedduuccee(()) function in List::Util).

 Can't goto subroutine outside a subroutine
     (F) The deeply magical "goto subroutine" call can only replace one
     subroutine call for another.  It can't manufacture one out of whole
     cloth.  In general you should be calling it out of only an AUTOLOAD
     routine anyway.  See "goto" in perlfunc.

 Can't ignore signal CHLD, forcing to default
     (W signal) Perl has detected that it is being run with the SIGCHLD
     signal (sometimes known as SIGCLD) disabled.  Since disabling this
     signal will interfere with proper determination of exit status of
     child processes, Perl has reset the signal to its default value.
     This situation typically indicates that the parent program under
     which Perl may be running (e.g. cron) is being very careless.

 Can't kill a non-numeric process ID
     (F) Process identifiers must be (signed) integers.  It is a fatal
     error to attempt to kkiillll(()) an undefined, empty-string or otherwise
     non-numeric process identifier.

 Can't "last" outside a loop block
     (F) A "last" statement was executed to break out of the current
     block, except that there's this itty bitty problem called there isn't
     a current block.  Note that an "if" or "else" block doesn't count as
     a "loopish" block, as doesn't a block given to ssoorrtt(()), mmaapp(()) or
     ggrreepp(()).  You can usually double the curlies to get the same effect
     though, because the inner curlies will be considered a block that
     loops once.  See "last" in perlfunc.

 Can't linearize anonymous symbol table
     (F) Perl tried to calculate the method resolution order (MRO) of a
     package, but failed because the package stash has no name.

 Can't load '%s' for module %s
     (F) The module you tried to load failed to load a dynamic extension.
     This may either mean that you upgraded your version of perl to one
     that is incompatible with your old dynamic extensions (which is known
     to happen between major versions of perl), or (more likely) that your
     dynamic extension was built against an older version of the library
     that is installed on your system.  You may need to rebuild your old
     dynamic extensions.

 Can't localize lexical variable %s
     (F) You used local on a variable name that was previously declared as
     a lexical variable using "my" or "state".  This is not allowed.  If
     you want to localize a package variable of the same name, qualify it
     with the package name.

 Can't localize through a reference
     (F) You said something like "local $$ref", which Perl can't currently
     handle, because when it goes to restore the old value of whatever
     $ref pointed to after the scope of the llooccaall(()) is finished, it can't
     be sure that $ref will still be a reference.

 Can't locate %s
     (F) You said to "do" (or "require", or "use") a file that couldn't be
     found.  Perl looks for the file in all the locations mentioned in
     @INC, unless the file name included the full path to the file.
     Perhaps you need to set the PERL5LIB or PERL5OPT environment variable
     to say where the extra library is, or maybe the script needs to add
     the library name to @INC.  Or maybe you just misspelled the name of
     the file.  See "require" in perlfunc and lib.

 Can't locate auto/%s.al in @INC
     (F) A function (or method) was called in a package which allows
     autoload, but there is no function to autoload.  Most probable causes
     are a misprint in a function/method name or a failure to "AutoSplit"
     the file, say, by doing "make install".

 Can't locate loadable object for module %s in @INC
     (F) The module you loaded is trying to load an external library, like
     for example, _f_o_o_._s_o or _b_a_r_._d_l_l, but the DynaLoader module was unable
     to locate this library.  See DynaLoader.

 Can't locate object method "%s" via package "%s"
     (F) You called a method correctly, and it correctly indicated a
     package functioning as a class, but that package doesn't define that
     particular method, nor does any of its base classes.  See perlobj.

 Can't locate object method "%s" via package "%s" (perhaps you forgot to
 load "%s"?)
     (F) You called a method on a class that did not exist, and the method
     could not be found in UNIVERSAL.  This often means that a method
     requires a package that has not been loaded.

 Can't locate package %s for @%s::ISA
     (W syntax) The @ISA array contained the name of another package that
     doesn't seem to exist.

 Can't locate PerlIO%s
     (F) You tried to use in ooppeenn(()) a PerlIO layer that does not exist,
     e.g. open(FH, ">:nosuchlayer", "somefile").

 Can't make list assignment to %ENV on this system
     (F) List assignment to %ENV is not supported on some systems, notably

VMS. #

 Can't make loaded symbols global on this platform while loading %s
     (S) A module passed the flag 0x01 to DDyynnaaLLooaaddeerr::::ddll__llooaadd__ffiillee(()) to
     request that symbols from the stated file are made available globally
     within the process, but that functionality is not available on this
     platform.  Whilst the module likely will still work, this may prevent
     the perl interpreter from loading other XS-based extensions which
     need to link directly to functions defined in the C or XS code in the
     stated file.

 Can't modify %s in %s
     (F) You aren't allowed to assign to the item indicated, or otherwise
     try to change it, such as with an auto-increment.

 Can't modify non-lvalue subroutine call of &%s
 Can't modify non-lvalue subroutine call of &%s in %s
     (F) Subroutines meant to be used in lvalue context should be declared
     as such.  See "Lvalue subroutines" in perlsub.

 Can't modify reference to %s in %s assignment
     (F) Only a limited number of constructs can be used as the argument
     to a reference constructor on the left-hand side of an assignment,
     and what you used was not one of them.  See "Assigning to References"
     in perlref.

 Can't modify reference to localized parenthesized array in list
 assignment
     (F) Assigning to "\local(@array)" or "\(local @array)" is not
     supported, as it is not clear exactly what it should do.  If you
     meant to make @array refer to some other array, use "\@array =
     \@other_array".  If you want to make the elements of @array aliases
     of the scalars referenced on the right-hand side, use "\(@array) =
     @scalar_refs".

 Can't modify reference to parenthesized hash in list assignment
     (F) Assigning to "\(%hash)" is not supported.  If you meant to make
     %hash refer to some other hash, use "\%hash = \%other_hash".  If you
     want to make the elements of %hash into aliases of the scalars
     referenced on the right-hand side, use a hash slice: "\@hash{@keys} =
     @those_scalar_refs".

 Can't msgrcv to read-only var
     (F) The target of a msgrcv must be modifiable to be used as a receive
     buffer.

 Can't "next" outside a loop block
     (F) A "next" statement was executed to reiterate the current block,
     but there isn't a current block.  Note that an "if" or "else" block
     doesn't count as a "loopish" block, as doesn't a block given to
     ssoorrtt(()), mmaapp(()) or ggrreepp(()).  You can usually double the curlies to get
     the same effect though, because the inner curlies will be considered
     a block that loops once.  See "next" in perlfunc.

 Can't open %s: %s
     (S inplace) The implicit opening of a file through use of the "<>"
     filehandle, either implicitly under the "-n" or "-p" command-line
     switches, or explicitly, failed for the indicated reason.  Usually
     this is because you don't have read permission for a file which you
     named on the command line.

     (F) You tried to call perl with the --ee switch, but _/_d_e_v_/_n_u_l_l (or your
     operating system's equivalent) could not be opened.

 Can't open a reference
     (W io) You tried to open a scalar reference for reading or writing,
     using the 3-arg ooppeenn(()) syntax:

         open FH, '>', $ref;

     but your version of perl is compiled without perlio, and this form of
     open is not supported.

 Can't open bidirectional pipe
     (W pipe) You tried to say "open(CMD, "|cmd|")", which is not
     supported.  You can try any of several modules in the Perl library to
     do this, such as IPC::Open2.  Alternately, direct the pipe's output
     to a file using ">", and then read it in under a different file
     handle.

 Can't open error file %s as stderr
     (F) An error peculiar to VMS.  Perl does its own command line
     redirection, and couldn't open the file specified after '2>' or '2>>'
     on the command line for writing.

 Can't open input file %s as stdin
     (F) An error peculiar to VMS.  Perl does its own command line
     redirection, and couldn't open the file specified after '<' on the
     command line for reading.

 Can't open output file %s as stdout
     (F) An error peculiar to VMS.  Perl does its own command line
     redirection, and couldn't open the file specified after '>' or '>>'
     on the command line for writing.

 Can't open output pipe (name: %s)
     (P) An error peculiar to VMS.  Perl does its own command line
     redirection, and couldn't open the pipe into which to send data
     destined for stdout.

 Can't open perl script "%s": %s
     (F) The script you specified can't be opened for the indicated
     reason.

     If you're debugging a script that uses #!, and normally relies on the
     shell's $PATH search, the -S option causes perl to do that search, so
     you don't have to type the path or "`which $scriptname`".

 Can't read CRTL environ
     (S) A warning peculiar to VMS.  Perl tried to read an element of %ENV
     from the CRTL's internal environment array and discovered the array
     was missing.  You need to figure out where your CRTL misplaced its
     environ or define _P_E_R_L___E_N_V___T_A_B_L_E_S (see perlvms) so that environ is
     not searched.

 Can't redeclare "%s" in "%s"
     (F) A "my", "our" or "state" declaration was found within another
     declaration, such as "my ($x, my($y), $z)" or "our (my $x)".

 Can't "redo" outside a loop block
     (F) A "redo" statement was executed to restart the current block, but
     there isn't a current block.  Note that an "if" or "else" block
     doesn't count as a "loopish" block, as doesn't a block given to
     ssoorrtt(()), mmaapp(()) or ggrreepp(()).  You can usually double the curlies to get
     the same effect though, because the inner curlies will be considered
     a block that loops once.  See "redo" in perlfunc.

 Can't remove %s: %s, skipping file
     (S inplace) You requested an inplace edit without creating a backup
     file.  Perl was unable to remove the original file to replace it with
     the modified file.  The file was left unmodified.

 Can't rename in-place work file '%s' to '%s': %s
     (F) When closed implicitly, the temporary file for in-place editing
     couldn't be renamed to the original filename.

 Can't rename %s to %s: %s, skipping file
     (F) The rename done by the --ii switch failed for some reason, probably
     because you don't have write permission to the directory.

 Can't reopen input pipe (name: %s) in binary mode
     (P) An error peculiar to VMS.  Perl thought stdin was a pipe, and
     tried to reopen it to accept binary data.  Alas, it failed.

 Can't represent character for Ox%X on this platform
     (F) There is a hard limit to how big a character code point can be
     due to the fundamental properties of UTF-8, especially on EBCDIC
     platforms.  The given code point exceeds that.  The only work-around
     is to not use such a large code point.

 Can't reset %ENV on this system
     (F) You called "reset('E')" or similar, which tried to reset all
     variables in the current package beginning with "E".  In the main
     package, that includes %ENV.  Resetting %ENV is not supported on some
     systems, notably VMS.

 Can't resolve method "%s" overloading "%s" in package "%s"
     (F)(P) Error resolving overloading specified by a method name (as
     opposed to a subroutine reference): no such method callable via the
     package.  If the method name is "???", this is an internal error.

 Can't return %s from lvalue subroutine
     (F) Perl detected an attempt to return illegal lvalues (such as
     temporary or readonly values) from a subroutine used as an lvalue.
     This is not allowed.

 Can't return outside a subroutine
     (F) The return statement was executed in mainline code, that is,
     where there was no subroutine call to return out of.  See perlsub.

 Can't return %s to lvalue scalar context
     (F) You tried to return a complete array or hash from an lvalue
     subroutine, but you called the subroutine in a way that made Perl
     think you meant to return only one value.  You probably meant to
     write parentheses around the call to the subroutine, which tell Perl
     that the call should be in list context.

 Can't take log of %g
     (F) For ordinary real numbers, you can't take the logarithm of a
     negative number or zero.  There's a Math::Complex package that comes
     standard with Perl, though, if you really want to do that for the
     negative numbers.

 Can't take sqrt of %g
     (F) For ordinary real numbers, you can't take the square root of a
     negative number.  There's a Math::Complex package that comes standard
     with Perl, though, if you really want to do that.

 Can't undef active subroutine
     (F) You can't undefine a routine that's currently running.  You can,
     however, redefine it while it's running, and you can even undef the
     redefined subroutine while the old routine is running.  Go figure.

 Can't unweaken a nonreference
     (F) You attempted to unweaken something that was not a reference.
     Only references can be unweakened.

 Can't upgrade %s (%d) to %d
     (P) The internal sv_upgrade routine adds "members" to an SV, making
     it into a more specialized kind of SV.  The top several SV types are
     so specialized, however, that they cannot be interconverted.  This
     message indicates that such a conversion was attempted.

 Can't use '%c' after -mname
     (F) You tried to call perl with the --mm switch, but you put something
     other than "=" after the module name.

 Can't use a hash as a reference
     (F) You tried to use a hash as a reference, as in "%foo->{"bar"}" or
     "%$ref->{"hello"}".  Versions of perl <= 5.22.0 used to allow this
     syntax, but shouldn't have.  This was deprecated in perl 5.6.1.

 Can't use an array as a reference
     (F) You tried to use an array as a reference, as in "@foo->[23]" or
     "@$ref->[99]".  Versions of perl <= 5.22.0 used to allow this syntax,
     but shouldn't have.  This was deprecated in perl 5.6.1.

 Can't use anonymous symbol table for method lookup
     (F) The internal routine that does method lookup was handed a symbol
     table that doesn't have a name.  Symbol tables can become anonymous
     for example by undefining stashes: "undef %Some::Package::".

 Can't use an undefined value as %s reference
     (F) A value used as either a hard reference or a symbolic reference
     must be a defined value.  This helps to delurk some insidious errors.

 Can't use bareword ("%s") as %s ref while "strict refs" in use
     (F) Only hard references are allowed by "strict refs".  Symbolic
     references are disallowed.  See perlref.

 Can't use %! because Errno.pm is not available
     (F) The first time the "%!" hash is used, perl automatically loads
     the Errno.pm module.  The Errno module is expected to tie the %! hash
     to provide symbolic names for $! errno values.

 Can't use both '<' and '>' after type '%c' in %s
     (F) A type cannot be forced to have both big-endian and little-endian
     byte-order at the same time, so this combination of modifiers is not
     allowed.  See "pack" in perlfunc.

 Can't use 'defined(@array)' (Maybe you should just omit the ddeeffiinneedd(())?)
     (F) ddeeffiinneedd(()) is not useful on arrays because it checks for an
     undefined _s_c_a_l_a_r value.  If you want to see if the array is empty,
     just use "if (@array) { # not empty }" for example.

 Can't use 'defined(%hash)' (Maybe you should just omit the ddeeffiinneedd(())?)
     (F) "defined()" is not usually right on hashes.

     Although "defined %hash" is false on a plain not-yet-used hash, it
     becomes true in several non-obvious circumstances, including
     iterators, weak references, stash names, even remaining true after
     "undef %hash".  These things make "defined %hash" fairly useless in
     practice, so it now generates a fatal error.

     If a check for non-empty is what you wanted then just put it in
     boolean context (see "Scalar values" in perldata):

         if (%hash) {
            # not empty
         }

     If you had "defined %Foo::Bar::QUUX" to check whether such a package
     variable exists then that's never really been reliable, and isn't a
     good way to enquire about the features of a package, or whether it's
     loaded, etc.

 Can't use %s for loop variable
     (P) The parser got confused when trying to parse a "foreach" loop.

 Can't use global %s in %s
     (F) You tried to declare a magical variable as a lexical variable.
     This is not allowed, because the magic can be tied to only one
     location (namely the global variable) and it would be incredibly
     confusing to have variables in your program that looked like magical
     variables but weren't.

 Can't use '%c' in a group with different byte-order in %s
     (F) You attempted to force a different byte-order on a type that is
     already inside a group with a byte-order modifier.  For example you
     cannot force little-endianness on a type that is inside a big-endian
     group.

 Can't use "my %s" in sort comparison
     (F) The global variables $a and $b are reserved for sort comparisons.
     You mentioned $a or $b in the same line as the <=> or cmp operator,
     and the variable had earlier been declared as a lexical variable.
     Either qualify the sort variable with the package name, or rename the
     lexical variable.

 Can't use %s ref as %s ref
     (F) You've mixed up your reference types.  You have to dereference a
     reference of the type needed.  You can use the rreeff(()) function to test
     the type of the reference, if need be.

 Can't use string ("%s") as %s ref while "strict refs" in use
 Can't use string ("%s"...) as %s ref while "strict refs" in use
     (F) You've told Perl to dereference a string, something which "use
     strict" blocks to prevent it happening accidentally.  See "Symbolic
     references" in perlref.  This can be triggered by an "@" or "$" in a
     double-quoted string immediately before interpolating a variable, for
     example in "user @$twitter_id", which says to treat the contents of
     $twitter_id as an array reference; use a "\" to have a literal "@"
     symbol followed by the contents of $twitter_id: "user \@$twitter_id".

 Can't use subscript on %s
     (F) The compiler tried to interpret a bracketed expression as a
     subscript.  But to the left of the brackets was an expression that
     didn't look like a hash or array reference, or anything else
     subscriptable.

 Can't use \%c to mean $%c in expression
     (W syntax) In an ordinary expression, backslash is a unary operator
     that creates a reference to its argument.  The use of backslash to
     indicate a backreference to a matched substring is valid only as part
     of a regular expression pattern.  Trying to do this in ordinary Perl
     code produces a value that prints out looking like SSCCAALLAARR(0xdecaf).
     Use the $1 form instead.

 Can't weaken a nonreference
     (F) You attempted to weaken something that was not a reference.  Only
     references can be weakened.

 Can't "when" outside a topicalizer
     (F) You have used a wwhheenn(()) block that is neither inside a "foreach"
     loop nor a "given" block.  (Note that this error is issued on exit
     from the "when" block, so you won't get the error if the match fails,
     or if you use an explicit "continue".)

 Can't x= to read-only value
     (F) You tried to repeat a constant value (often the undefined value)
     with an assignment operator, which implies modifying the value
     itself.  Perhaps you need to copy the value to a temporary, and
     repeat that.

 Character following "\c" must be printable ASCII
     (F) In "\c_X", _X must be a printable (non-control) ASCII character.

     Note that ASCII characters that don't map to control characters are
     discouraged, and will generate the warning (when enabled) ""\c%c" is
     more clearly written simply as "%s"".

 Character following \%c must be '{' or a single-character Unicode
 property name in regex; marked by <-- HERE in m/%s/
     (F) (In the above the %c is replaced by either "p" or "P".)  You
     specified something that isn't a legal Unicode property name.  Most
     Unicode properties are specified by "\p{...}".  But if the name is a
     single character one, the braces may be omitted.

 Character in 'C' format wrapped in pack
     (W pack) You said

         pack("C", $x)

     where $x is either less than 0 or more than 255; the "C" format is
     only for encoding native operating system characters (ASCII, EBCDIC,
     and so on) and not for Unicode characters, so Perl behaved as if you
     meant

         pack("C", $x & 255)

     If you actually want to pack Unicode codepoints, use the "U" format
     instead.

 Character in 'c' format wrapped in pack
     (W pack) You said

         pack("c", $x)

     where $x is either less than -128 or more than 127; the "c" format is
     only for encoding native operating system characters (ASCII, EBCDIC,
     and so on) and not for Unicode characters, so Perl behaved as if you
     meant

         pack("c", $x & 255);

     If you actually want to pack Unicode codepoints, use the "U" format
     instead.

 Character in '%c' format wrapped in unpack
     (W unpack) You tried something like

        unpack("H", "\x{2a1}")

     where the format expects to process a byte (a character with a value
     below 256), but a higher value was provided instead.  Perl uses the
     value modulus 256 instead, as if you had provided:

        unpack("H", "\x{a1}")

 Character in 'W' format wrapped in pack
     (W pack) You said

         pack("U0W", $x)

     where $x is either less than 0 or more than 255.  However, "U0"-mode
     expects all values to fall in the interval [0, 255], so Perl behaved
     as if you meant:

         pack("U0W", $x & 255)

 Character(s) in '%c' format wrapped in pack
     (W pack) You tried something like

        pack("u", "\x{1f3}b")

     where the format expects to process a sequence of bytes (character
     with a value below 256), but some of the characters had a higher
     value.  Perl uses the character values modulus 256 instead, as if you
     had provided:

        pack("u", "\x{f3}b")

 Character(s) in '%c' format wrapped in unpack
     (W unpack) You tried something like

        unpack("s", "\x{1f3}b")

     where the format expects to process a sequence of bytes (character
     with a value below 256), but some of the characters had a higher
     value.  Perl uses the character values modulus 256 instead, as if you
     had provided:

        unpack("s", "\x{f3}b")

 charnames alias definitions may not contain a sequence of multiple
 spaces; marked by <-- HERE in %s
     (F) You defined a character name which had multiple space characters
     in a row.  Change them to single spaces.  Usually these names are
     defined in the ":alias" import argument to "use charnames", but they
     could be defined by a translator installed into $^H{charnames}.  See
     "CUSTOM ALIASES" in charnames.

 cchhddiirr(()) on unopened filehandle %s
     (W unopened) You tried cchhddiirr(()) on a filehandle that was never opened.

 "\c%c" is more clearly written simply as "%s"
     (W syntax) The "\c_X" construct is intended to be a way to specify
     non-printable characters.  You used it for a printable one, which is
     better written as simply itself, perhaps preceded by a backslash for
     non-word characters.  Doing it the way you did is not portable
     between ASCII and EBCDIC platforms.

 Cloning substitution context is unimplemented
     (F) Creating a new thread inside the "s///" operator is not
     supported.

 cclloosseeddiirr(()) attempted on invalid dirhandle %s
     (W io) The dirhandle you tried to close is either closed or not
     really a dirhandle.  Check your control flow.

 cclloossee(()) on unopened filehandle %s
     (W unopened) You tried to close a filehandle that was never opened.

 Closure prototype called
     (F) If a closure has attributes, the subroutine passed to an
     attribute handler is the prototype that is cloned when a new closure
     is created.  This subroutine cannot be called.

 \C no longer supported in regex; marked by <-- HERE in m/%s/
     (F) The \C character class used to allow a match of single byte
     within a multi-byte utf-8 character, but was removed in v5.24 as it
     broke encapsulation and its implementation was extremely buggy.  If
     you really need to process the individual bytes, you probably want to
     convert your string to one where each underlying byte is stored as a
     character, with uuttff88::::eennccooddee(()).

 Code missing after '/'
     (F) You had a (sub-)template that ends with a '/'.  There must be
     another template code following the slash.  See "pack" in perlfunc.

 Code point 0x%X is not Unicode, and not portable
     (S non_unicode portable) You had a code point that has never been in
     any standard, so it is likely that languages other than Perl will NOT
     understand it.  This code point also will not fit in a 32-bit word on
     ASCII platforms and therefore is non-portable between systems.

     At one time, it was legal in some standards to have code points up to
     0x7FFF_FFFF, but not higher, and this code point is higher.

     Acceptance of these code points is a Perl extension, and you should
     expect that nothing other than Perl can handle them; Perl itself on
     EBCDIC platforms before v5.24 does not handle them.

     Perl also makes no guarantees that the representation of these code
     points won't change at some point in the future, say when machines
     become available that have larger than a 64-bit word.  At that time,
     files containing any of these, written by an older Perl might require
     conversion before being readable by a newer Perl.

 Code point 0x%X is not Unicode, may not be portable
     (S non_unicode) You had a code point above the Unicode maximum of

U+10FFFF. #

     Perl allows strings to contain a superset of Unicode code points, but
     these may not be accepted by other languages/systems.  Further, even
     if these languages/systems accept these large code points, they may
     have chosen a different representation for them than the UTF-8-like
     one that Perl has, which would mean files are not exchangeable
     between them and Perl.

     On EBCDIC platforms, code points above 0x3FFF_FFFF have a different
     representation in Perl v5.24 than before, so any file containing
     these that was written before that version will require conversion
     before being readable by a later Perl.

 %s: Command not found
     (A) You've accidentally run your script through ccsshh or another shell
     instead of Perl.  Check the #! line, or manually feed your script
     into Perl yourself.  The #! line at the top of your file could look
     like

       #!/usr/bin/perl

 %s: command not found
     (A) You've accidentally run your script through bbaasshh or another shell
     instead of Perl.  Check the #! line, or manually feed your script
     into Perl yourself.  The #! line at the top of your file could look
     like

       #!/usr/bin/perl

 %s: command not found: %s
     (A) You've accidentally run your script through zzsshh or another shell
     instead of Perl.  Check the #! line, or manually feed your script
     into Perl yourself.  The #! line at the top of your file could look
     like

       #!/usr/bin/perl

 Compilation failed in require
     (F) Perl could not compile a file specified in a "require" statement.
     Perl uses this generic message when none of the errors that it
     encountered were severe enough to halt compilation immediately.

 Complex regular subexpression recursion limit (%d) exceeded
     (W regexp) The regular expression engine uses recursion in complex
     situations where back-tracking is required.  Recursion depth is
     limited to 32766, or perhaps less in architectures where the stack
     cannot grow arbitrarily.  ("Simple" and "medium" situations are
     handled without recursion and are not subject to a limit.)  Try
     shortening the string under examination; looping in Perl code (e.g.
     with "while") rather than in the regular expression engine; or
     rewriting the regular expression so that it is simpler or backtracks
     less.  (See perlfaq2 for information on _M_a_s_t_e_r_i_n_g _R_e_g_u_l_a_r
     _E_x_p_r_e_s_s_i_o_n_s.)

 ccoonnnneecctt(()) on closed socket %s
     (W closed) You tried to do a connect on a closed socket.  Did you
     forget to check the return value of your ssoocckkeett(()) call?  See
     "connect" in perlfunc.

 Constant(%s): Call to &{$^H{%s}} did not return a defined value
     (F) The subroutine registered to handle constant overloading (see
     overload) or a custom charnames handler (see "CUSTOM TRANSLATORS" in
     charnames) returned an undefined value.

 Constant(%s): $^H{%s} is not defined
     (F) The parser found inconsistencies while attempting to define an
     overloaded constant.  Perhaps you forgot to load the corresponding
     overload pragma?

 Constant is not %s reference
     (F) A constant value (perhaps declared using the "use constant"
     pragma) is being dereferenced, but it amounts to the wrong type of
     reference.  The message indicates the type of reference that was
     expected.  This usually indicates a syntax error in dereferencing the
     constant value.  See "Constant Functions" in perlsub and constant.

 Constants from lexical variables potentially modified elsewhere are no
 longer permitted
     (F) You wrote something like

         my $var;
         $sub = sub () { $var };

     but $var is referenced elsewhere and could be modified after the
     "sub" expression is evaluated.  Either it is explicitly modified
     elsewhere ("$var = 3") or it is passed to a subroutine or to an
     operator like "printf" or "map", which may or may not modify the
     variable.

     Traditionally, Perl has captured the value of the variable at that
     point and turned the subroutine into a constant eligible for
     inlining.  In those cases where the variable can be modified
     elsewhere, this breaks the behavior of closures, in which the
     subroutine captures the variable itself, rather than its value, so
     future changes to the variable are reflected in the subroutine's
     return value.

     This usage was deprecated, and as of Perl 5.32 is no longer allowed,
     making it possible to change the behavior in the future.

     If you intended for the subroutine to be eligible for inlining, then
     make sure the variable is not referenced elsewhere, possibly by
     copying it:

         my $var2 = $var;
         $sub = sub () { $var2 };

     If you do want this subroutine to be a closure that reflects future
     changes to the variable that it closes over, add an explicit
     "return":

         my $var;
         $sub = sub () { return $var };

 Constant subroutine %s redefined
     (W redefine)(S) You redefined a subroutine which had previously been
     eligible for inlining.  See "Constant Functions" in perlsub for
     commentary and workarounds.

 Constant subroutine %s undefined
     (W misc) You undefined a subroutine which had previously been
     eligible for inlining.  See "Constant Functions" in perlsub for
     commentary and workarounds.

 Constant(%s) unknown
     (F) The parser found inconsistencies either while attempting to
     define an overloaded constant, or when trying to find the character
     name specified in the "\N{...}" escape.  Perhaps you forgot to load
     the corresponding overload pragma?

 :const is experimental
     (S experimental::const_attr) The "const" attribute is experimental.
     If you want to use the feature, disable the warning with "no warnings
     'experimental::const_attr'", but know that in doing so you are taking
     the risk that your code may break in a future Perl version.

 :const is not permitted on named subroutines
     (F) The "const" attribute causes an anonymous subroutine to be run
     and its value captured at the time that it is cloned.  Named
     subroutines are not cloned like this, so the attribute does not make
     sense on them.

 Copy method did not return a reference
     (F) The method which overloads "=" is buggy.  See "Copy Constructor"
     in overload.

 &CORE::%s cannot be called directly
     (F) You tried to call a subroutine in the "CORE::" namespace with
     &foo syntax or through a reference.  Some subroutines in this package
     cannot yet be called that way, but must be called as barewords.
     Something like this will work:

         BEGIN { *shove = \&CORE::push; }
         shove @array, 1,2,3; # pushes on to @array

 CORE::%s is not a keyword
     (F) The CORE:: namespace is reserved for Perl keywords.

 Corrupted regexp opcode %d > %d
     (P) This is either an error in Perl, or, if you're using one, your
     custom regular expression engine.  If not the latter, report the
     problem to <https://github.com/Perl/perl5/issues>.

 corrupted regexp pointers
     (P) The regular expression engine got confused by what the regular
     expression compiler gave it.

 corrupted regexp program
     (P) The regular expression engine got passed a regexp program without
     a valid magic number.

 Corrupt malloc ptr 0x%x at 0x%x
     (P) The malloc package that comes with Perl had an internal failure.

 Count after length/code in unpack
     (F) You had an unpack template indicating a counted-length string,
     but you have also specified an explicit size for the string.  See
     "pack" in perlfunc.

 Declaring references is experimental
     (S experimental::declared_refs) This warning is emitted if you use a
     reference constructor on the right-hand side of "my", "state", "our",
     or "local".  Simply suppress the warning if you want to use the
     feature, but know that in doing so you are taking the risk of using
     an experimental feature which may change or be removed in a future
     Perl version:

         no warnings "experimental::declared_refs";
         use feature "declared_refs";
         $fooref = my \$foo;

 Deep recursion on anonymous subroutine
 Deep recursion on subroutine "%s"
     (W recursion) This subroutine has called itself (directly or
     indirectly) 100 times more than it has returned.  This probably
     indicates an infinite recursion, unless you're writing strange
     benchmark programs, in which case it indicates something else.

     This threshold can be changed from 100, by recompiling the _p_e_r_l
     binary, setting the C pre-processor macro "PERL_SUB_DEPTH_WARN" to
     the desired value.

 (?(DEFINE)....) does not allow branches in regex; marked by <-- HERE in
 m/%s/
     (F) You used something like "(?(DEFINE)...|..)" which is illegal.
     The most likely cause of this error is that you left out a
     parenthesis inside of the "...." part.

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 %s defines neither package nor VERSION--version check failed
     (F) You said something like "use Module 42" but in the Module file
     there are neither package declarations nor a $VERSION.

 delete argument is not a HASH or ARRAY element or slice
     (F) The argument to "delete" must be either a hash or array element,
     such as:

         $foo{$bar}
         $ref->{"susie"}[12]

     or a hash or array slice, such as:

         @foo[$bar, $baz, $xyzzy]
         $ref->[12]->@{"susie", "queue"}

     or a hash key/value or array index/value slice, such as:

         %foo[$bar, $baz, $xyzzy]
         $ref->[12]->%{"susie", "queue"}

 Delimiter for here document is too long
     (F) In a here document construct like "<<FOO", the label "FOO" is too
     long for Perl to handle.  You have to be seriously twisted to write
     code that triggers this error.

 DESTROY created new reference to dead object '%s'
     (F) A DDEESSTTRROOYY(()) method created a new reference to the object which is
     just being DESTROYed.  Perl is confused, and prefers to abort rather
     than to create a dangling reference.

 Did not produce a valid header
     See "500 Server error".

 %s did not return a true value
     (F) A required (or used) file must return a true value to indicate
     that it compiled correctly and ran its initialization code correctly.
     It's traditional to end such a file with a "1;", though any true
     value would do.  See "require" in perlfunc.

 (Did you mean &%s instead?)
     (W misc) You probably referred to an imported subroutine &FOO as $FOO
     or some such.

 (Did you mean "local" instead of "our"?)
     (W shadow) Remember that "our" does not localize the declared global
     variable.  You have declared it again in the same lexical scope,
     which seems superfluous.

 (Did you mean $ or @ instead of %?)
     (W) You probably said %hash{$key} when you meant $hash{$key} or
     @hash{@keys}.  On the other hand, maybe you just meant %hash and got
     carried away.

 Died
     (F) You passed ddiiee(()) an empty string (the equivalent of "die """) or
     you called it with no args and $@ was empty.

 Document contains no data
     See "500 Server error".

 %s does not define %s::VERSION--version check failed
     (F) You said something like "use Module 42" but the Module did not
     define a $VERSION.

 '/' does not take a repeat count in %s
     (F) You cannot put a repeat count of any kind right after the '/'
     code.  See "pack" in perlfunc.

 do "%s" failed, '.' is no longer in @INC; did you mean do "./%s"?
     (D deprecated) Previously " do "somefile"; " would search the current
     directory for the specified file.  Since perl v5.26.0, _. has been
     removed from @INC by default, so this is no longer true.  To search
     the current directory (and only the current directory) you can write
     " do "./somefile"; ".

 Don't know how to get file name
     (P) "PerlIO_getname", a perl internal I/O function specific to VMS,
     was somehow called on another platform.  This should not happen.

 Don't know how to handle magic of type \%o
     (P) The internal handling of magical variables has been cursed.

 Downgrading a use VERSION declaration to below v5.11 is deprecated
     (S deprecated) This warning is emitted on a "use VERSION" statement
     that requests a version below v5.11 (when the effects of "use strict"
     would be disabled), after a previous declaration of one having a
     larger number (which would have enabled these effects). Because of a
     change to the way that "use VERSION" interacts with the strictness
     flags, this is no longer supported.

 (Do you need to predeclare %s?)
     (S syntax) This is an educated guess made in conjunction with the
     message "%s found where operator expected".  It often means a
     subroutine or module name is being referenced that hasn't been
     declared yet.  This may be because of ordering problems in your file,
     or because of a missing "sub", "package", "require", or "use"
     statement.  If you're referencing something that isn't defined yet,
     you don't actually have to define the subroutine or package before
     the current location.  You can use an empty "sub foo;" or "package
     FOO;" to enter a "forward" declaration.

 dduummpp(()) must be written as CCOORREE::::dduummpp(()) as of Perl 5.30
     (F) You used the obsolete "dump()" built-in function.  That was
     deprecated in Perl 5.8.0.  As of Perl 5.30 it must be written in
     fully qualified format: "CORE::dump()".

     See "dump" in perlfunc.

 dump is not supported
     (F) Your machine doesn't support dump/undump.

 Duplicate ffrreeee(()) ignored
     (S malloc) An internal routine called ffrreeee(()) on something that had
     already been freed.

 Duplicate modifier '%c' after '%c' in %s
     (W unpack) You have applied the same modifier more than once after a
     type in a pack template.  See "pack" in perlfunc.

 each on anonymous %s will always start from the beginning
     (W syntax) You called each on an anonymous hash or array.  Since a
     new hash or array is created each time, eeaacchh(()) will restart iterating
     over your hash or array every time.

 elseif should be elsif
     (S syntax) There is no keyword "elseif" in Perl because Larry thinks
     it's ugly.  Your code will be interpreted as an attempt to call a
     method named "elseif" for the class returned by the following block.
     This is unlikely to be what you want.

 Empty \%c in regex; marked by <-- HERE in m/%s/
 Empty \%c{}
 Empty \%c{} in regex; marked by <-- HERE in m/%s/
     (F) You used something like "\b{}", "\B{}", "\o{}", "\p", "\P", or
     "\x" without specifying anything for it to operate on.

     Unfortunately, for backwards compatibility reasons, an empty "\x" is
     legal outside "use re 'strict'" and expands to a NUL character.

 Empty (?) without any modifiers in regex; marked by <-- HERE in m/%s/
     (W regexp) (only under "use re 'strict'") "(?)" does nothing, so
     perhaps this is a typo.

 ${^ENCODING} is no longer supported
     (F) The special variable "${^ENCODING}", formerly used to implement
     the "encoding" pragma, is no longer supported as of Perl 5.26.0.

     Setting it to anything other than "undef" is a fatal error as of Perl
     5.28.

 entering effective %s failed
     (F) While under the "use filetest" pragma, switching the real and
     effective uids or gids failed.

 %ENV is aliased to %s
     (F) You're running under taint mode, and the %ENV variable has been
     aliased to another hash, so it doesn't reflect anymore the state of
     the program's environment.  This is potentially insecure.

 Error converting file specification %s
     (F) An error peculiar to VMS.  Because Perl may have to deal with
     file specifications in either VMS or Unix syntax, it converts them to
     a single form when it must operate on them directly.  Either you've
     passed an invalid file specification to Perl, or you've found a case
     the conversion routines don't handle.  Drat.

 Error %s in expansion of %s
     (F) An error was encountered in handling a user-defined property
     ("User-Defined Character Properties" in perlunicode).  These are
     programmer written subroutines, hence subject to errors that may
     prevent them from compiling or running.  The calls to these subs are
     "eval"'d, and if there is a failure, this message is raised, using
     the contents of $@ from the failed "eval".

     Another possibility is that tainted data was encountered somewhere in
     the chain of expanding the property.  If so, the message wording will
     indicate that this is the problem.  See "Insecure user-defined
     property %s".

 Eval-group in insecure regular expression
     (F) Perl detected tainted data when trying to compile a regular
     expression that contains the "(?{ ... })" zero-width assertion, which
     is unsafe.  See "(?{ code })" in perlre, and perlsec.

 Eval-group not allowed at runtime, use re 'eval' in regex m/%s/
     (F) Perl tried to compile a regular expression containing the "(?{
     ... })" zero-width assertion at run time, as it would when the
     pattern contains interpolated values.  Since that is a security risk,
     it is not allowed.  If you insist, you may still do this by using the
     "re 'eval'" pragma or by explicitly building the pattern from an
     interpolated string at run time and using that in an eevvaall(()).  See
     "(?{ code })" in perlre.

 Eval-group not allowed, use re 'eval' in regex m/%s/
     (F) A regular expression contained the "(?{ ... })" zero-width
     assertion, but that construct is only allowed when the "use re
     'eval'" pragma is in effect.  See "(?{ code })" in perlre.

 EVAL without pos change exceeded limit in regex; marked by <-- HERE in
 m/%s/
     (F) You used a pattern that nested too many EVAL calls without
     consuming any text.  Restructure the pattern so that text is
     consumed.

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 Excessively long <> operator
     (F) The contents of a <> operator may not exceed the maximum size of
     a Perl identifier.  If you're just trying to glob a long list of
     filenames, try using the gglloobb(()) operator, or put the filenames into a
     variable and glob that.

 exec? I'm not *that* kind of operating system
     (F) The "exec" function is not implemented on some systems, e.g.
     Catamount. See perlport.

 %sExecution of %s aborted due to compilation errors.
     (F) The final summary message when a Perl compilation fails.

 exists argument is not a HASH or ARRAY element or a subroutine
     (F) The argument to "exists" must be a hash or array element or a
     subroutine with an ampersand, such as:

         $foo{$bar}
         $ref->{"susie"}[12]
         &do_something

 exists argument is not a subroutine name
     (F) The argument to "exists" for "exists &sub" must be a subroutine
     name, and not a subroutine call.  "exists &sub()" will generate this
     error.

 Exiting eval via %s
     (W exiting) You are exiting an eval by unconventional means, such as
     a goto, or a loop control statement.

 Exiting format via %s
     (W exiting) You are exiting a format by unconventional means, such as
     a goto, or a loop control statement.

 Exiting pseudo-block via %s
     (W exiting) You are exiting a rather special block construct (like a
     sort block or subroutine) by unconventional means, such as a goto, or
     a loop control statement.  See "sort" in perlfunc.

 Exiting subroutine via %s
     (W exiting) You are exiting a subroutine by unconventional means,
     such as a goto, or a loop control statement.

 Exiting substitution via %s
     (W exiting) You are exiting a substitution by unconventional means,
     such as a return, a goto, or a loop control statement.

 Expecting close bracket in regex; marked by <-- HERE in m/%s/
     (F) You wrote something like

      (?13

     to denote a capturing group of the form "(?_P_A_R_N_O)", but omitted the
     ")".

 Expecting interpolated extended charclass in regex; marked by <-- HERE in
 m/%s/
     (F) It looked like you were attempting to interpolate an already-
     compiled extended character class, like so:

      my $thai_or_lao = qr/(?[ \p{Thai} + \p{Lao} ])/;
      ...
      qr/(?[ \p{Digit} & $thai_or_lao ])/;

     But the marked code isn't syntactically correct to be such an
     interpolated class.

 Experimental aliasing via reference not enabled
     (F) To do aliasing via references, you must first enable the feature:

         no warnings "experimental::refaliasing";
         use feature "refaliasing";
         \$x = \$y;

 Experimental %s on scalar is now forbidden
     (F) An experimental feature added in Perl 5.14 allowed "each",
     "keys", "push", "pop", "shift", "splice", "unshift", and "values" to
     be called with a scalar argument.  This experiment is considered
     unsuccessful, and has been removed.  The "postderef" feature may meet
     your needs better.

 Experimental subroutine signatures not enabled
     (F) To use subroutine signatures, you must first enable them:

         use feature "signatures";
         sub foo ($left, $right) { ... }

 Explicit blessing to '' (assuming package main)
     (W misc) You are blessing a reference to a zero length string.  This
     has the effect of blessing the reference into the package main.  This
     is usually not what you want.  Consider providing a default target
     package, e.g. bless($ref, $p || 'MyPackage');

 %s: Expression syntax
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 %s failed--call queue aborted
     (F) An untrapped exception was raised while executing a UNITCHECK,
     CHECK, INIT, or END subroutine.  Processing of the remainder of the
     queue of such routines has been prematurely ended.

 Failed to close in-place work file %s: %s
     (F) Closing an output file from in-place editing, as with the "-i"
     command-line switch, failed.

 False [] range "%s" in regex; marked by <-- HERE in m/%s/
     (W regexp)(F) A character class range must start and end at a literal
     character, not another character class like "\d" or "[:alpha:]".  The
     "-" in your false range is interpreted as a literal "-".  In a
     "(?[...])" construct, this is an error, rather than a warning.
     Consider quoting the "-", "\-".  The <-- HERE shows whereabouts in
     the regular expression the problem was discovered.  See perlre.

 Fatal VMS error (status=%d) at %s, line %d
     (P) An error peculiar to VMS.  Something untoward happened in a VMS
     system service or RTL routine; Perl's exit status should provide more
     details.  The filename in "at %s" and the line number in "line %d"
     tell you which section of the Perl source code is distressed.

 fcntl is not implemented
     (F) Your machine apparently doesn't implement ffccnnttll(()).  What is this,
     a PDP-11 or something?

 FETCHSIZE returned a negative value
     (F) A tied array claimed to have a negative number of elements, which
     is not possible.

 Field too wide in 'u' format in pack
     (W pack) Each line in an uuencoded string starts with a length
     indicator which can't encode values above 63.  So there is no point
     in asking for a line length bigger than that.  Perl will behave as if
     you specified "u63" as the format.

 Filehandle %s opened only for input
     (W io) You tried to write on a read-only filehandle.  If you intended
     it to be a read-write filehandle, you needed to open it with "+<" or
     "+>" or "+>>" instead of with "<" or nothing.  If you intended only
     to write the file, use ">" or ">>".  See "open" in perlfunc.

 Filehandle %s opened only for output
     (W io) You tried to read from a filehandle opened only for writing,
     If you intended it to be a read/write filehandle, you needed to open
     it with "+<" or "+>" or "+>>" instead of with ">".  If you intended
     only to read from the file, use "<".  See "open" in perlfunc.
     Another possibility is that you attempted to open filedescriptor 0
     (also known as STDIN) for output (maybe you closed STDIN earlier?).

 Filehandle %s reopened as %s only for input
     (W io) You opened for reading a filehandle that got the same
     filehandle id as STDOUT or STDERR.  This occurred because you closed
     STDOUT or STDERR previously.

 Filehandle STDIN reopened as %s only for output
     (W io) You opened for writing a filehandle that got the same
     filehandle id as STDIN.  This occurred because you closed STDIN
     previously.

 Final $ should be \$ or $name
     (F) You must now decide whether the final $ in a string was meant to
     be a literal dollar sign, or was meant to introduce a variable name
     that happens to be missing.  So you have to put either the backslash
     or the name.

 defer is experimental
     (S experimental::defer) The "defer" block modifier is experimental.
     If you want to use the feature, disable the warning with "no warnings
     'experimental::defer'", but know that in doing so you are taking the
     risk that your code may break in a future Perl version.

 fflloocckk(()) on closed filehandle %s
     (W closed) The filehandle you're attempting to fflloocckk(()) got itself
     closed some time before now.  Check your control flow.  fflloocckk(())
     operates on filehandles.  Are you attempting to call fflloocckk(()) on a
     dirhandle by the same name?

 for my (...) is experimental
     (S experimental::for_list) This warning is emitted if you use "for"
     to iterate multiple values at a time. This syntax is currently
     experimental and its behaviour may change in future releases of Perl.

 Format not terminated
     (F) A format must be terminated by a line with a solitary dot.  Perl
     got to the end of your file without finding such a line.

 Format %s redefined
     (W redefine) You redefined a format.  To suppress this warning, say

         {
             no warnings 'redefine';
             eval "format NAME =...";
         }

 Found = in conditional, should be ==
     (W syntax) You said

         if ($foo = 123)

     when you meant

         if ($foo == 123)

     (or something like that).

 %s found where operator expected
     (S syntax) The Perl lexer knows whether to expect a term or an
     operator.  If it sees what it knows to be a term when it was
     expecting to see an operator, it gives you this warning.  Usually it
     indicates that an operator or delimiter was omitted, such as a
     semicolon.

 gdbm store returned %d, errno %d, key "%s"
     (S) A warning from the GDBM_File extension that a store failed.

 gethostent not implemented
     (F) Your C library apparently doesn't implement ggeetthhoosstteenntt(()),
     probably because if it did, it'd feel morally obligated to return
     every hostname on the Internet.

 get%ssnnaammee(()) on closed socket %s
     (W closed) You tried to get a socket or peer socket name on a closed
     socket.  Did you forget to check the return value of your ssoocckkeett(())
     call?

 getpwnam returned invalid UIC %#o for user "%s"
     (S) A warning peculiar to VMS.  The call to "sys$getuai" underlying
     the "getpwnam" operator returned an invalid UIC.

 ggeettssoocckkoopptt(()) on closed socket %s
     (W closed) You tried to get a socket option on a closed socket.  Did
     you forget to check the return value of your ssoocckkeett(()) call?  See
     "getsockopt" in perlfunc.

 given is experimental
     (S experimental::smartmatch) "given" depends on smartmatch, which is
     experimental, so its behavior may change or even be removed in any
     future release of perl.  See the explanation under "Experimental
     Details on given and when" in perlsyn.

 Global symbol "%s" requires explicit package name (did you forget to
 declare "my %s"?)
     (F) You've said "use strict" or "use strict vars", which indicates
     that all variables must either be lexically scoped (using "my" or
     "state"), declared beforehand using "our", or explicitly qualified to
     say which package the global variable is in (using "::").

 glob failed (%s)
     (S glob) Something went wrong with the external program(s) used for
     "glob" and "<*.c>".  Usually, this means that you supplied a "glob"
     pattern that caused the external program to fail and exit with a
     nonzero status.  If the message indicates that the abnormal exit
     resulted in a coredump, this may also mean that your csh (C shell) is
     broken.  If so, you should change all of the csh-related variables in
     config.sh:  If you have tcsh, make the variables refer to it as if it
     were csh (e.g. "full_csh='/usr/bin/tcsh'"); otherwise, make them all
     empty (except that "d_csh" should be 'undef') so that Perl will think
     csh is missing.  In either case, after editing config.sh, run
     "./Configure -S" and rebuild Perl.

 Glob not terminated
     (F) The lexer saw a left angle bracket in a place where it was
     expecting a term, so it's looking for the corresponding right angle
     bracket, and not finding it.  Chances are you left some needed
     parentheses out earlier in the line, and you really meant a "less
     than".

 gmtime(%f) failed
     (W overflow) You called "gmtime" with a number that it could not
     handle: too large, too small, or NaN.  The returned value is "undef".

 gmtime(%f) too large
     (W overflow) You called "gmtime" with a number that was larger than
     it can reliably handle and "gmtime" probably returned the wrong date.
     This warning is also triggered with NaN (the special not-a-number
     value).

 gmtime(%f) too small
     (W overflow) You called "gmtime" with a number that was smaller than
     it can reliably handle and "gmtime" probably returned the wrong date.

 Got an error from DosAllocMem
     (P) An error peculiar to OS/2.  Most probably you're using an
     obsolete version of Perl, and this should not happen anyway.

 goto must have label
     (F) Unlike with "next" or "last", you're not allowed to goto an
     unspecified destination.  See "goto" in perlfunc.

 Goto undefined subroutine%s
     (F) You tried to call a subroutine with "goto &sub" syntax, but the
     indicated subroutine hasn't been defined, or if it was, it has since
     been undefined.

 Group name must start with a non-digit word character in regex; marked by
 <-- HERE in m/%s/
     (F) Group names must follow the rules for perl identifiers, meaning
     they must start with a non-digit word character.  A common cause of
     this error is using (?&0) instead of (?0).  See perlre.

 ()-group starts with a count
     (F) A ()-group started with a count.  A count is supposed to follow
     something: a template character or a ()-group.  See "pack" in
     perlfunc.

 %s had compilation errors.
     (F) The final summary message when a "perl -c" fails.

 Had to create %s unexpectedly
     (S internal) A routine asked for a symbol from a symbol table that
     ought to have existed already, but for some reason it didn't, and had
     to be created on an emergency basis to prevent a core dump.

 %s has too many errors
     (F) The parser has given up trying to parse the program after 10
     errors.  Further error messages would likely be uninformative.

 Hexadecimal float: exponent overflow
     (W overflow) The hexadecimal floating point has a larger exponent
     than the floating point supports.

 Hexadecimal float: exponent underflow
     (W overflow) The hexadecimal floating point has a smaller exponent
     than the floating point supports.  With the IEEE 754 floating point,
     this may also mean that the subnormals (formerly known as denormals)
     are being used, which may or may not be an error.

 Hexadecimal float: internal error (%s)
     (F) Something went horribly bad in hexadecimal float handling.

 Hexadecimal float: mantissa overflow
     (W overflow) The hexadecimal floating point literal had more bits in
     the mantissa (the part between the 0x and the exponent, also known as
     the fraction or the significand) than the floating point supports.

 Hexadecimal float: precision loss
     (W overflow) The hexadecimal floating point had internally more
     digits than could be output.  This can be caused by unsupported long
     double formats, or by 64-bit integers not being available (needed to
     retrieve the digits under some configurations).

 Hexadecimal float: unsupported long double format
     (F) You have configured Perl to use long doubles but the internals of
     the long double format are unknown; therefore the hexadecimal float
     output is impossible.

 Hexadecimal number > 0xffffffff non-portable
     (W portable) The hexadecimal number you specified is larger than
     2**32-1 (4294967295) and therefore non-portable between systems.  See
     perlport for more on portability concerns.

 Identifier too long
     (F) Perl limits identifiers (names for variables, functions, etc.) to
     about 250 characters for simple names, and somewhat more for compound
     names (like $A::B).  You've exceeded Perl's limits.  Future versions
     of Perl are likely to eliminate these arbitrary limitations.

 Ignoring zero length \N{} in character class in regex; marked by <-- HERE
 in m/%s/
     (W regexp) Named Unicode character escapes ("\N{...}") may return a
     zero-length sequence.  When such an escape is used in a character
     class its behavior is not well defined.  Check that the correct
     escape has been used, and the correct charname handler is in scope.

 Illegal %s digit '%c' ignored
     (W digit) Here %s is one of "binary", "octal", or "hex".  You may
     have tried to use a digit other than one that is legal for the given
     type, such as only 0 and 1 for binary.  For octals, this is raised
     only if the illegal character is an '8' or '9'.  For hex, 'A' - 'F'
     and 'a' - 'f' are legal.  Interpretation of the number stopped just
     before the offending digit or character.

 Illegal binary digit '%c'
     (F) You used a digit other than 0 or 1 in a binary number.

 Illegal character after '_' in prototype for %s : %s
     (W illegalproto) An illegal character was found in a prototype
     declaration.  The '_' in a prototype must be followed by a ';',
     indicating the rest of the parameters are optional, or one of '@' or
     '%', since those two will accept 0 or more final parameters.

 Illegal character \%o (carriage return)
     (F) Perl normally treats carriage returns in the program text as it
     would any other whitespace, which means you should never see this
     error when Perl was built using standard options.  For some reason,
     your version of Perl appears to have been built without this support.
     Talk to your Perl administrator.

 Illegal character following sigil in a subroutine signature
     (F) A parameter in a subroutine signature contained an unexpected
     character following the "$", "@" or "%" sigil character.  Normally
     the sigil should be followed by the variable name or "=" etc.
     Perhaps you are trying use a prototype while in the scope of "use
     feature 'signatures'"?  For example:

         sub foo ($$) {}            # legal - a prototype

         use feature 'signatures;
         sub foo ($$) {}            # illegal - was expecting a signature
         sub foo ($a, $b)
                 :prototype($$) {}  # legal

 Illegal character in prototype for %s : %s
     (W illegalproto) An illegal character was found in a prototype
     declaration.  Legal characters in prototypes are $, @, %, *, ;, [, ],
     &, \, and +.  Perhaps you were trying to write a subroutine signature
     but didn't enable that feature first ("use feature 'signatures'"), so
     your signature was instead interpreted as a bad prototype.

 Illegal declaration of anonymous subroutine
     (F) When using the "sub" keyword to construct an anonymous
     subroutine, you must always specify a block of code.  See perlsub.

 Illegal declaration of subroutine %s
     (F) A subroutine was not declared correctly.  See perlsub.

 Illegal division by zero
     (F) You tried to divide a number by 0.  Either something was wrong in
     your logic, or you need to put a conditional in to guard against
     meaningless input.

 Illegal modulus zero
     (F) You tried to divide a number by 0 to get the remainder.  Most
     numbers don't take to this kindly.

 Illegal number of bits in vec
     (F) The number of bits in vveecc(()) (the third argument) must be a power
     of two from 1 to 32 (or 64, if your platform supports that).

 Illegal octal digit '%c'
     (F) You used an 8 or 9 in an octal number.

 Illegal operator following parameter in a subroutine signature
     (F) A parameter in a subroutine signature, was followed by something
     other than "=" introducing a default, "," or ")".

         use feature 'signatures';
         sub foo ($=1) {}           # legal
         sub foo ($a = 1) {}        # legal
         sub foo ($a += 1) {}       # illegal
         sub foo ($a == 1) {}       # illegal

 Illegal pattern in regex; marked by <-- HERE in m/%s/
     (F) You wrote something like

      (?+foo)

     The "+" is valid only when followed by digits, indicating a capturing
     group.  See "(?_P_A_R_N_O)".

 Illegal suidscript
     (F) The script run under suidperl was somehow illegal.

 Illegal switch in PERL5OPT: -%c
     (X) The PERL5OPT environment variable may only be used to set the
     following switches: --[[CCDDIIMMUUddmmttww]].

 Illegal user-defined property name
     (F) You specified a Unicode-like property name in a regular
     expression pattern (using "\p{}" or "\P{}") that Perl knows isn't an
     official Unicode property, and was likely meant to be a user-defined
     property name, but it can't be one of those, as they must begin with
     either "In" or "Is".  Check the spelling.  See also "Can't find
     Unicode property definition "%s"".

 Ill-formed CRTL environ value "%s"
     (W internal) A warning peculiar to VMS.  Perl tried to read the
     CRTL's internal environ array, and encountered an element without the
     "=" delimiter used to separate keys from values.  The element is
     ignored.

 Ill-formed message in prime_env_iter: |%s|
     (W internal) A warning peculiar to VMS.  Perl tried to read a logical
     name or CLI symbol definition when preparing to iterate over %ENV,
     and didn't see the expected delimiter between key and value, so the
     line was ignored.

 (in cleanup) %s
     (W misc) This prefix usually indicates that a DDEESSTTRROOYY(()) method raised
     the indicated exception.  Since destructors are usually called by the
     system at arbitrary points during execution, and often a vast number
     of times, the warning is issued only once for any number of failures
     that would otherwise result in the same message being repeated.

     Failure of user callbacks dispatched using the "G_KEEPERR" flag could
     also result in this warning.  See "G_KEEPERR" in perlcall.

 Implicit use of @_ in %s with signatured subroutine is experimental
     (S experimental::args_array_with_signatures) An expression that
     implicitly involves the @_ arguments array was found in a subroutine
     that uses a signature.  This is experimental because the interaction
     between the arguments array and parameter handling via signatures is
     not guaranteed to remain stable in any future version of Perl, and
     such code should be avoided.

 Incomplete expression within '(?[ ])' in regex; marked by <-- HERE in
 m/%s/
     (F) There was a syntax error within the "(?[ ])".  This can happen if
     the expression inside the construct was completely empty, or if there
     are too many or few operands for the number of operators.  Perl is
     not smart enough to give you a more precise indication as to what is
     wrong.

 Inconsistent hierarchy during C3 merge of class '%s': merging failed on
 parent '%s'
     (F) The method resolution order (MRO) of the given class is not
     C3-consistent, and you have enabled the C3 MRO for this class.  See
     the C3 documentation in mro for more information.

 Indentation on line %d of here-doc doesn't match delimiter
     (F) You have an indented here-document where one or more of its lines
     have whitespace at the beginning that does not match the closing
     delimiter.

     For example, line 2 below is wrong because it does not have at least
     2 spaces, but lines 1 and 3 are fine because they have at least 2:

         if ($something) {
           print <<~EOF;
             Line 1
            Line 2 not
               Line 3

EOF #

         }

     Note that tabs and spaces are compared strictly, meaning 1 tab will
     not match 8 spaces.

 Infinite recursion in regex
     (F) You used a pattern that references itself without consuming any
     input text.  You should check the pattern to ensure that recursive
     patterns either consume text or fail.

 Infinite recursion in user-defined property
     (F) A user-defined property ("User-Defined Character Properties" in
     perlunicode) can depend on the definitions of other user-defined
     properties.  If the chain of dependencies leads back to this
     property, infinite recursion would occur, were it not for the check
     that raised this error.

     Restructure your property definitions to avoid this.

 Infinite recursion via empty pattern
     (F) You tried to use the empty pattern inside of a regex code block,
     for instance "/(?{ s!!! })/", which resulted in re-executing the same
     pattern, which is an infinite loop which is broken by throwing an
     exception.

 Initialization of state variables in list currently forbidden
     (F) "state" only permits initializing a single variable, specified
     without parentheses.  So "state $a = 42" and "state @a = qw(a b c)"
     are allowed, but not "state ($a) = 42" or "(state $a) = 42".  To
     initialize more than one "state" variable, initialize them one at a
     time.

 %%s[%s] in scalar context better written as $%s[%s]
     (W syntax) In scalar context, you've used an array index/value slice
     (indicated by %) to select a single element of an array.  Generally
     it's better to ask for a scalar value (indicated by $).  The
     difference is that $foo[&bar] always behaves like a scalar, both in
     the value it returns and when evaluating its argument, while
     %foo[&bar] provides a list context to its subscript, which can do
     weird things if you're expecting only one subscript.  When called in
     list context, it also returns the index (what &bar returns) in
     addition to the value.

 %%s{%s} in scalar context better written as $%s{%s}
     (W syntax) In scalar context, you've used a hash key/value slice
     (indicated by %) to select a single element of a hash.  Generally
     it's better to ask for a scalar value (indicated by $).  The
     difference is that $foo{&bar} always behaves like a scalar, both in
     the value it returns and when evaluating its argument, while
     @foo{&bar} and provides a list context to its subscript, which can do
     weird things if you're expecting only one subscript.  When called in
     list context, it also returns the key in addition to the value.

 Insecure dependency in %s
     (F) You tried to do something that the tainting mechanism didn't
     like.  The tainting mechanism is turned on when you're running setuid
     or setgid, or when you specify --TT to turn it on explicitly.  The
     tainting mechanism labels all data that's derived directly or
     indirectly from the user, who is considered to be unworthy of your
     trust.  If any such data is used in a "dangerous" operation, you get
     this error.  See perlsec for more information.

 Insecure directory in %s
     (F) You can't use ssyysstteemm(()), eexxeecc(()), or a piped open in a setuid or
     setgid script if $ENV{PATH} contains a directory that is writable by
     the world.  Also, the PATH must not contain any relative directory.
     See perlsec.

 Insecure $ENV{%s} while running %s
     (F) You can't use ssyysstteemm(()), eexxeecc(()), or a piped open in a setuid or
     setgid script if any of $ENV{PATH}, $ENV{IFS}, $ENV{CDPATH},
     $ENV{ENV}, $ENV{BASH_ENV} or $ENV{TERM} are derived from data
     supplied (or potentially supplied) by the user.  The script must set
     the path to a known value, using trustworthy data.  See perlsec.

 Insecure user-defined property %s
     (F) Perl detected tainted data when trying to compile a regular
     expression that contains a call to a user-defined character property
     function, i.e. "\p{IsFoo}" or "\p{InFoo}".  See "User-Defined
     Character Properties" in perlunicode and perlsec.

 Integer overflow in format string for %s
     (F) The indexes and widths specified in the format string of
     "printf()" or "sprintf()" are too large.  The numbers must not
     overflow the size of integers for your architecture.

 Integer overflow in %s number
     (S overflow) The hexadecimal, octal or binary number you have
     specified either as a literal or as an argument to hheexx(()) or oocctt(()) is
     too big for your architecture, and has been converted to a floating
     point number.  On a 32-bit architecture the largest hexadecimal,
     octal or binary number representable without overflow is 0xFFFFFFFF,
     037777777777, or 0b11111111111111111111111111111111 respectively.
     Note that Perl transparently promotes all numbers to a floating point
     representation internally--subject to loss of precision errors in
     subsequent operations.

 Integer overflow in srand
     (S overflow) The number you have passed to srand is too big to fit in
     your architecture's integer representation.  The number has been
     replaced with the largest integer supported (0xFFFFFFFF on 32-bit
     architectures).  This means you may be getting less randomness than
     you expect, because different random seeds above the maximum will
     return the same sequence of random numbers.

 Integer overflow in version
 Integer overflow in version %d
     (W overflow) Some portion of a version initialization is too large
     for the size of integers for your architecture.  This is not a
     warning because there is no rational reason for a version to try and
     use an element larger than typically 2**32.  This is usually caused
     by trying to use some odd mathematical operation as a version, like
     100/9.

 Internal disaster in regex; marked by <-- HERE in m/%s/
     (P) Something went badly wrong in the regular expression parser.  The
     <-- HERE shows whereabouts in the regular expression the problem was
     discovered.

 Internal inconsistency in tracking vforks
     (S) A warning peculiar to VMS.  Perl keeps track of the number of
     times you've called "fork" and "exec", to determine whether the
     current call to "exec" should affect the current script or a
     subprocess (see "exec LIST" in perlvms).  Somehow, this count has
     become scrambled, so Perl is making a guess and treating this "exec"
     as a request to terminate the Perl script and execute the specified
     command.

 internal %<num>p might conflict with future printf extensions
     (S internal) Perl's internal routine that handles "printf" and
     "sprintf" formatting follows a slightly different set of rules when
     called from C or XS code.  Specifically, formats consisting of digits
     followed by "p" (e.g., "%7p") are reserved for future use.  If you
     see this message, then an XS module tried to call that routine with
     one such reserved format.

 Internal urp in regex; marked by <-- HERE in m/%s/
     (P) Something went badly awry in the regular expression parser.  The
     <-- HERE shows whereabouts in the regular expression the problem was
     discovered.

 %s (...) interpreted as function
     (W syntax) You've run afoul of the rule that says that any list
     operator followed by parentheses turns into a function, with all the
     list operators arguments found inside the parentheses.  See "Terms
     and List Operators (Leftward)" in perlop.

 In '(?...)', the '(' and '?' must be adjacent in regex; marked by
 <-- HERE in m/%s/
     (F) The two-character sequence "(?" in this context in a regular
     expression pattern should be an indivisible token, with nothing
     intervening between the "(" and the "?", but you separated them with
     whitespace.

 In '(*...)', the '(' and '*' must be adjacent in regex; marked by
 <-- HERE in m/%s/
     (F) The two-character sequence "(*" in this context in a regular
     expression pattern should be an indivisible token, with nothing
     intervening between the "(" and the "*", but you separated them.  Fix
     the pattern and retry.

 Invalid %s attribute: %s
     (F) The indicated attribute for a subroutine or variable was not
     recognized by Perl or by a user-supplied handler.  See attributes.

 Invalid %s attributes: %s
     (F) The indicated attributes for a subroutine or variable were not
     recognized by Perl or by a user-supplied handler.  See attributes.

 Invalid character in charnames alias definition; marked by <-- HERE in
 '%s (F) You tried to create a custom alias for a character name, with the
     ":alias" option to "use charnames" and the specified character in the
     indicated name isn't valid.  See "CUSTOM ALIASES" in charnames.

 Invalid \0 character in %s for %s: %s\0%s
     (W syscalls) Embedded \0 characters in pathnames or other system call
     arguments produce a warning as of 5.20.  The parts after the \0 were
     formerly ignored by system calls.

 Invalid character in \N{...}; marked by <-- HERE in \N{%s}
     (F) Only certain characters are valid for character names.  The
     indicated one isn't.  See "CUSTOM ALIASES" in charnames.

 Invalid conversion in %s: "%s"
     (W printf) Perl does not understand the given format conversion.  See
     "sprintf" in perlfunc.

 Invalid escape in the specified encoding in regex; marked by <-- HERE in
 m/%s/
     (W regexp)(F) The numeric escape (for example "\xHH") of value < 256
     didn't correspond to a single character through the conversion from
     the encoding specified by the encoding pragma.  The escape was
     replaced with REPLACEMENT CHARACTER (U+FFFD) instead, except within
     "(?[   ])", where it is a fatal error.  The <-- HERE shows
     whereabouts in the regular expression the escape was discovered.

 Invalid hexadecimal number in \N{U+...}
 Invalid hexadecimal number in \N{U+...} in regex; marked by <-- HERE in
 m/%s/
     (F) The character constant represented by "..." is not a valid
     hexadecimal number.  Either it is empty, or you tried to use a
     character other than 0 - 9 or A - F, a - f in a hexadecimal number.

 Invalid module name %s with -%c option: contains single ':'
     (F) The module argument to perl's --mm and --MM command-line options
     cannot contain single colons in the module name, but only in the
     arguments after "=".  In other words, --MMFFoooo::::BBaarr==::bbaazz is ok, but
     --MMFFoooo::BBaarr==bbaazz is not.

 Invalid mro name: '%s'
     (F) You tried to "mro::set_mro("classname", "foo")" or "use mro
     'foo'", where "foo" is not a valid method resolution order (MRO).
     Currently, the only valid ones supported are "dfs" and "c3", unless
     you have loaded a module that is a MRO plugin.  See mro and
     perlmroapi.

 Invalid negative number (%s) in chr
     (W utf8) You passed a negative number to "chr".  Negative numbers are
     not valid character numbers, so it returns the Unicode replacement
     character (U+FFFD).

 Invalid number '%s' for -C option.
     (F) You supplied a number to the -C option that either has extra
     leading zeroes or overflows perl's unsigned integer representation.

 invalid option -D%c, use -D'' to see choices
     (S debugging) Perl was called with invalid debugger flags.  Call perl
     with the --DD option with no flags to see the list of acceptable
     values.  See also "-Dletters" in perlrun.

 Invalid quantifier in {,} in regex; marked by <-- HERE in m/%s/
     (F) The pattern looks like a {min,max} quantifier, but the min or max
     could not be parsed as a valid number - either it has leading zeroes,
     or it represents too big a number to cope with.  The <-- HERE shows
     where in the regular expression the problem was discovered.  See
     perlre.

 Invalid [] range "%s" in regex; marked by <-- HERE in m/%s/
     (F) The range specified in a character class had a minimum character
     greater than the maximum character.  One possibility is that you
     forgot the "{}" from your ending "\x{}" - "\x" without the curly
     braces can go only up to "ff".  The <-- HERE shows whereabouts in the
     regular expression the problem was discovered.  See perlre.

 Invalid range "%s" in transliteration operator
     (F) The range specified in the tr/// or y/// operator had a minimum
     character greater than the maximum character.  See perlop.

 Invalid reference to group in regex; marked by <-- HERE in m/%s/
     (F) The capture group you specified can't possibly exist because the
     number you used is not within the legal range of possible values for
     this machine.

 Invalid separator character %s in attribute list
     (F) Something other than a colon or whitespace was seen between the
     elements of an attribute list.  If the previous attribute had a
     parenthesised parameter list, perhaps that list was terminated too
     soon.  See attributes.

 Invalid separator character %s in PerlIO layer specification %s
     (W layer) When pushing layers onto the Perl I/O system, something
     other than a colon or whitespace was seen between the elements of a
     layer list.  If the previous attribute had a parenthesised parameter
     list, perhaps that list was terminated too soon.

 Invalid strict version format (%s)
     (F) A version number did not meet the "strict" criteria for versions.
     A "strict" version number is a positive decimal number (integer or
     decimal-fraction) without exponentiation or else a dotted-decimal
     v-string with a leading 'v' character and at least three components.
     The parenthesized text indicates which criteria were not met.  See
     the version module for more details on allowed version formats.

 Invalid type '%s' in %s
     (F) The given character is not a valid pack or unpack type.  See
     "pack" in perlfunc.

     (W) The given character is not a valid pack or unpack type but used
     to be silently ignored.

 Invalid version format (%s)
     (F) A version number did not meet the "lax" criteria for versions.  A
     "lax" version number is a positive decimal number (integer or
     decimal-fraction) without exponentiation or else a dotted-decimal
     v-string.  If the v-string has fewer than three components, it must
     have a leading 'v' character.  Otherwise, the leading 'v' is
     optional.  Both decimal and dotted-decimal versions may have a
     trailing "alpha" component separated by an underscore character after
     a fractional or dotted-decimal component.  The parenthesized text
     indicates which criteria were not met.  See the version module for
     more details on allowed version formats.

 Invalid version object
     (F) The internal structure of the version object was invalid.
     Perhaps the internals were modified directly in some way or an
     arbitrary reference was blessed into the "version" class.

 In '(*VERB...)', the '(' and '*' must be adjacent in regex; marked by
 <-- HERE in m/%s/
 Inverting a character class which contains a multi-character sequence is
 illegal in regex; marked by <-- HERE in m/%s/
     (F) You wrote something like

      qr/\P{name=KATAKANA LETTER AINU P}/
      qr/[^\p{name=KATAKANA LETTER AINU P}]/

     This name actually evaluates to a sequence of two Katakana
     characters, not just a single one, and it is illegal to try to take
     the complement of a sequence.  (Mathematically it would mean any
     sequence of characters from 0 to infinity in length that weren't
     these two in a row, and that is likely not of any real use.)

     (F) The two-character sequence "(*" in this context in a regular
     expression pattern should be an indivisible token, with nothing
     intervening between the "(" and the "*", but you separated them.

 ioctl is not implemented
     (F) Your machine apparently doesn't implement iiooccttll(()), which is
     pretty strange for a machine that supports C.

 iiooccttll(()) on unopened %s
     (W unopened) You tried iiooccttll(()) on a filehandle that was never opened.
     Check your control flow and number of arguments.

 IO layers (like '%s') unavailable
     (F) Your Perl has not been configured to have PerlIO, and therefore
     you cannot use IO layers.  To have PerlIO, Perl must be configured
     with 'useperlio'.

 IO::Socket::atmark not implemented on this architecture
     (F) Your machine doesn't implement the ssoocckkaattmmaarrkk(()) functionality,
     neither as a system call nor an ioctl call (SIOCATMARK).

 '%s' is an unknown bound type in regex; marked by <-- HERE in m/%s/
     (F) You used "\b{...}" or "\B{...}" and the "..." is not known to
     Perl.  The current valid ones are given in "\b{}, \b, \B{}, \B" in
     perlrebackslash.

 %s is forbidden - matches null string many times in regex; marked by
 <-- HERE in m/%s/
     (F) The pattern you've specified might cause the regular expression
     to infinite loop so it is forbidden.  The <-- HERE shows whereabouts
     in the regular expression the problem was discovered.  See perlre.

 %s() isn't allowed on :utf8 handles
     (F) The ssyyssrreeaadd(()), rreeccvv(()), ssyysswwrriittee(()) and sseenndd(()) operators are not
     allowed on handles that have the ":utf8" layer, either explicitly, or
     implicitly, eg., with the ":encoding(UTF-16LE)" layer.

     Previously ssyyssrreeaadd(()) and rreeccvv(()) currently use only the ":utf8" flag
     for the stream, ignoring the actual layers.  Since ssyyssrreeaadd(()) and
     rreeccvv(()) did no UTF-8 validation they can end up creating invalidly
     encoded scalars.

     Similarly, ssyysswwrriittee(()) and sseenndd(()) used only the ":utf8" flag,
     otherwise ignoring any layers.  If the flag is set, both wrote the
     value UTF-8 encoded, even if the layer is some different encoding,
     such as the example above.

     Ideally, all of these operators would completely ignore the ":utf8"
     state, working only with bytes, but this would result in silently
     breaking existing code.

 "%s" is more clearly written simply as "%s" in regex; marked by <-- HERE
 in m/%s/
     (W regexp) (only under "use re 'strict'" or within "(?[...])")

     You specified a character that has the given plainer way of writing
     it, and which is also portable to platforms running with different
     character sets.

 $* is no longer supported as of Perl 5.30
     (F) The special variable $*, deprecated in older perls, was removed
     in 5.10.0, is no longer supported and is a fatal error as of Perl
     5.30.  In previous versions of perl the use of $* enabled or disabled
     multi-line matching within a string.

     Instead of using $* you should use the "/m" (and maybe "/s") regexp
     modifiers.  You can enable "/m" for a lexical scope (even a whole
     file) with "use re '/m'".  (In older versions: when $* was set to a
     true value then all regular expressions behaved as if they were
     written using "/m".)

     Use of this variable will be a fatal error in Perl 5.30.

 $# is no longer supported as of Perl 5.30
     (F) The special variable $#, deprecated in older perls, was removed
     as of 5.10.0, is no longer supported and is a fatal error as of Perl
     5.30.  You should use the printf/sprintf functions instead.

 '%s' is not a code reference
     (W overload) The second (fourth, sixth, ...) argument of
     overload::constant needs to be a code reference.  Either an anonymous
     subroutine, or a reference to a subroutine.

 '%s' is not an overloadable type
     (W overload) You tried to overload a constant type the overload
     package is unaware of.

 '%s' is not recognised as a builtin function
     (F) An attempt was made to "use" the builtin pragma module to create
     a lexical alias for an unknown function name.

 -i used with no filenames on the command line, reading from STDIN
     (S inplace) The "-i" option was passed on the command line,
     indicating that the script is intended to edit files in place, but no
     files were given.  This is usually a mistake, since editing STDIN in
     place doesn't make sense, and can be confusing because it can make
     perl look like it is hanging when it is really just trying to read
     from STDIN.  You should either pass a filename to edit, or remove
     "-i" from the command line.  See perlrun for more details.

 Junk on end of regexp in regex m/%s/
     (P) The regular expression parser is confused.

 \K not permitted in lookahead/lookbehind in regex; marked by <-- HERE in
 m/%s/
     (F) Your regular expression used "\K" in a lookahead or lookbehind
     assertion, which currently isn't permitted.

     This may change in the future, see Support \K in lookarounds
     <https://github.com/Perl/perl5/issues/18134>.

 Label not found for "last %s"
     (F) You named a loop to break out of, but you're not currently in a
     loop of that name, not even if you count where you were called from.
     See "last" in perlfunc.

 Label not found for "next %s"
     (F) You named a loop to continue, but you're not currently in a loop
     of that name, not even if you count where you were called from.  See
     "last" in perlfunc.

 Label not found for "redo %s"
     (F) You named a loop to restart, but you're not currently in a loop
     of that name, not even if you count where you were called from.  See
     "last" in perlfunc.

 leaving effective %s failed
     (F) While under the "use filetest" pragma, switching the real and
     effective uids or gids failed.

 length/code after end of string in unpack
     (F) While unpacking, the string buffer was already used up when an
     unpack length/code combination tried to obtain more data.  This
     results in an undefined value for the length.  See "pack" in
     perlfunc.

 lleennggtthh(()) used on %s (did you mean "scalar(%s)"?)
     (W syntax) You used lleennggtthh(()) on either an array or a hash when you
     probably wanted a count of the items.

     Array size can be obtained by doing:

         scalar(@array);

     The number of items in a hash can be obtained by doing:

         scalar(keys %hash);

 Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
     (F) An extension is attempting to insert text into the current parse
     (using lex_stuff_pvn or similar), but tried to insert a character
     that couldn't be part of the current input.  This is an inherent
     pitfall of the stuffing mechanism, and one of the reasons to avoid
     it.  Where it is necessary to stuff, stuffing only plain ASCII is
     recommended.

 Lexing code internal error (%s)
     (F) Lexing code supplied by an extension violated the lexer's API in
     a detectable way.

 lliisstteenn(()) on closed socket %s
     (W closed) You tried to do a listen on a closed socket.  Did you
     forget to check the return value of your ssoocckkeett(()) call?  See "listen"
     in perlfunc.

 List form of piped open not implemented
     (F) On some platforms, notably Windows, the three-or-more-arguments
     form of "open" does not support pipes, such as "open($pipe, '|-',
     @args)".  Use the two-argument "open($pipe, '|prog arg1 arg2...')"
     form instead.

 Literal vertical space in [] is illegal except under /x in regex; marked
 by <-- HERE in m/%s/
     (F) (only under "use re 'strict'" or within "(?[...])")

     Likely you forgot the "/x" modifier or there was a typo in the
     pattern.  For example, did you really mean to match a form-feed?  If
     so, all the ASCII vertical space control characters are representable
     by escape sequences which won't present such a jarring appearance as
     your pattern does when displayed.

       \r    carriage return
       \f    form feed
       \n    line feed
       \cK   vertical tab

 %s: loadable library and perl binaries are mismatched (got %s handshake
 key %p, needed %p)
     (P) A dynamic loading library ".so" or ".dll" was being loaded into
     the process that was built against a different build of perl than the
     said library was compiled against.  Reinstalling the XS module will
     likely fix this error.

 Locale '%s' contains (at least) the following characters which have
 unexpected meanings: %s  The Perl program will use the expected meanings
     (W locale) You are using the named UTF-8 locale.  UTF-8 locales are
     expected to have very particular behavior, which most do.  This
     message arises when perl found some departures from the expectations,
     and is notifying you that the expected behavior overrides these
     differences.  In some cases the differences are caused by the locale
     definition being defective, but the most common causes of this
     warning are when there are ambiguities and conflicts in following the
     Standard, and the locale has chosen an approach that differs from
     Perl's.

     One of these is because that, contrary to the claims, Unicode is not
     completely locale insensitive.  Turkish and some related languages
     have two types of "I" characters.  One is dotted in both upper- and
     lowercase, and the other is dotless in both cases.  Unicode allows a
     locale to use either the Turkish rules, or the rules used in all
     other instances, where there is only one type of "I", which is
     dotless in the uppercase, and dotted in the lower.  The perl core
     does not (yet) handle the Turkish case, and this message warns you of
     that.  Instead, the Unicode::Casing module allows you to mostly
     implement the Turkish casing rules.

     The other common cause is for the characters

      $ + < = > ^ ` | ~

     These are problematic.  The C standard says that these should be
     considered punctuation in the C locale (and the POSIX standard defers
     to the C standard), and Unicode is generally considered a superset of
     the C locale.  But Unicode has added an extra category, "Symbol", and
     classifies these particular characters as being symbols.  Most UTF-8
     locales have them treated as punctuation, so that iissppuunncctt(2) returns
     non-zero for them.  But a few locales have it return 0.   Perl takes
     the first approach, not using "ispunct()" at all (see Note [5] in
     perlrecharclass), and this message is raised to notify you that you
     are getting Perl's approach, not the locale's.

 Locale '%s' may not work well.%s
     (W locale) You are using the named locale, which is a non-UTF-8 one,
     and which perl has determined is not fully compatible with what it
     can handle.  The second %s gives a reason.

     By far the most common reason is that the locale has characters in it
     that are represented by more than one byte.  The only such locales
     that Perl can handle are the UTF-8 locales.  Most likely the
     specified locale is a non-UTF-8 one for an East Asian language such
     as Chinese or Japanese.  If the locale is a superset of ASCII, the
     ASCII portion of it may work in Perl.

     Some essentially obsolete locales that aren't supersets of ASCII,
     mainly those in ISO 646 or other 7-bit locales, such as ASMO 449, can
     also have problems, depending on what portions of the ASCII character
     set get changed by the locale and are also used by the program.  The
     warning message lists the determinable conflicting characters.

     Note that not all incompatibilities are found.

     If this happens to you, there's not much you can do except switch to
     use a different locale or use Encode to translate from the locale
     into UTF-8; if that's impracticable, you have been warned that some
     things may break.

     This message is output once each time a bad locale is switched into
     within the scope of "use locale", or on the first possibly-affected
     operation if the "use locale" inherits a bad one.  It is not raised
     for any operations from the POSIX module.

 localtime(%f) failed
     (W overflow) You called "localtime" with a number that it could not
     handle: too large, too small, or NaN.  The returned value is "undef".

 localtime(%f) too large
     (W overflow) You called "localtime" with a number that was larger
     than it can reliably handle and "localtime" probably returned the
     wrong date.  This warning is also triggered with NaN (the special
     not-a-number value).

 localtime(%f) too small
     (W overflow) You called "localtime" with a number that was smaller
     than it can reliably handle and "localtime" probably returned the
     wrong date.

 Lookbehind longer than %d not implemented in regex m/%s/
     (F) There is currently a limit on the length of string which
     lookbehind can handle.  This restriction may be eased in a future
     release.

 Lost precision when %s %f by 1
     (W imprecision) You attempted to increment or decrement a value by
     one, but the result is too large for the underlying floating point
     representation to store accurately. Hence, the target of "++" or "--"
     is increased or decreased by quite different value than one, such as
     zero (_i_._e_. the target is unchanged) or two, due to rounding.  Perl
     issues this warning because it has already switched from integers to
     floating point when values are too large for integers, and now even
     floating point is insufficient.  You may wish to switch to using
     Math::BigInt explicitly.

 llssttaatt(()) on filehandle%s
     (W io) You tried to do an lstat on a filehandle.  What did you mean
     by that?  llssttaatt(()) makes sense only on filenames.  (Perl did a ffssttaatt(())
     instead on the filehandle.)

 lvalue attribute %s already-defined subroutine
     (W misc) Although attributes.pm allows this, turning the lvalue
     attribute on or off on a Perl subroutine that is already defined does
     not always work properly.  It may or may not do what you want,
     depending on what code is inside the subroutine, with exact details
     subject to change between Perl versions.  Only do this if you really
     know what you are doing.

 lvalue attribute ignored after the subroutine has been defined
     (W misc) Using the ":lvalue" declarative syntax to make a Perl
     subroutine an lvalue subroutine after it has been defined is not
     permitted.  To make the subroutine an lvalue subroutine, add the
     lvalue attribute to the definition, or put the "sub foo :lvalue;"
     declaration before the definition.

     See also attributes.pm.

 Magical list constants are not supported
     (F) You assigned a magical array to a stash element, and then tried
     to use the subroutine from the same slot.  You are asking Perl to do
     something it cannot do, details subject to change between Perl
     versions.

 Malformed integer in [] in pack
     (F) Between the brackets enclosing a numeric repeat count only digits
     are permitted.  See "pack" in perlfunc.

 Malformed integer in [] in unpack
     (F) Between the brackets enclosing a numeric repeat count only digits
     are permitted.  See "pack" in perlfunc.

 Malformed PERLLIB_PREFIX
     (F) An error peculiar to OS/2.  PERLLIB_PREFIX should be of the form

         prefix1;prefix2

     or
         prefix1 prefix2

     with nonempty prefix1 and prefix2.  If "prefix1" is indeed a prefix
     of a builtin library search path, prefix2 is substituted.  The error
     may appear if components are not found, or are too long.  See
     "PERLLIB_PREFIX" in perlos2.

 Malformed prototype for %s: %s
     (F) You tried to use a function with a malformed prototype.  The
     syntax of function prototypes is given a brief compile-time check for
     obvious errors like invalid characters.  A more rigorous check is run
     when the function is called.  Perhaps the function's author was
     trying to write a subroutine signature but didn't enable that feature
     first ("use feature 'signatures'"), so the signature was instead
     interpreted as a bad prototype.

 Malformed UTF-8 character%s
     (S utf8)(F) Perl detected a string that should be UTF-8, but didn't
     comply with UTF-8 encoding rules, or represents a code point whose
     ordinal integer value doesn't fit into the word size of the current
     platform (overflows).  Details as to the exact malformation are given
     in the variable, %s, part of the message.

     One possible cause is that you set the UTF8 flag yourself for data
     that you thought to be in UTF-8 but it wasn't (it was for example
     legacy 8-bit data).  To guard against this, you can use
     "Encode::decode('UTF-8', ...)".

     If you use the ":encoding(UTF-8)" PerlIO layer for input, invalid
     byte sequences are handled gracefully, but if you use ":utf8", the
     flag is set without validating the data, possibly resulting in this
     error message.

     See also "Handling Malformed Data" in Encode.

 Malformed UTF-8 returned by \N{%s} immediately after '%s'
     (F) The charnames handler returned malformed UTF-8.

 Malformed UTF-8 string in "%s"
     (F) This message indicates a bug either in the Perl core or in XS
     code. Such code was trying to find out if a character, allegedly
     stored internally encoded as UTF-8, was of a given type, such as
     being punctuation or a digit.  But the character was not encoded in
     legal UTF-8.  The %s is replaced by a string that can be used by
     knowledgeable people to determine what the type being checked against
     was.

     Passing malformed strings was deprecated in Perl 5.18, and became
     fatal in Perl 5.26.

 Malformed UTF-8 string in '%c' format in unpack
     (F) You tried to unpack something that didn't comply with UTF-8
     encoding rules and perl was unable to guess how to make more
     progress.

 Malformed UTF-8 string in pack
     (F) You tried to pack something that didn't comply with UTF-8
     encoding rules and perl was unable to guess how to make more
     progress.

 Malformed UTF-8 string in unpack
     (F) You tried to unpack something that didn't comply with UTF-8
     encoding rules and perl was unable to guess how to make more
     progress.

 Malformed UTF-16 surrogate
     (F) Perl thought it was reading UTF-16 encoded character data but
     while doing it Perl met a malformed Unicode surrogate.

 Mandatory parameter follows optional parameter
     (F) In a subroutine signature, you wrote something like "$a = undef,
     $b", making an earlier parameter optional and a later one mandatory.
     Parameters are filled from left to right, so it's impossible for the
     caller to omit an earlier one and pass a later one.  If you want to
     act as if the parameters are filled from right to left, declare the
     rightmost optional and then shuffle the parameters around in the
     subroutine's body.

 Matched non-Unicode code point 0x%X against Unicode property; may not be
 portable
     (S non_unicode) Perl allows strings to contain a superset of Unicode
     code points; each code point may be as large as what is storable in a
     signed integer on your system, but these may not be accepted by other
     languages/systems.  This message occurs when you matched a string
     containing such a code point against a regular expression pattern,
     and the code point was matched against a Unicode property, "\p{...}"
     or "\P{...}".  Unicode properties are only defined on Unicode code
     points, so the result of this match is undefined by Unicode, but Perl
     (starting in v5.20) treats non-Unicode code points as if they were
     typical unassigned Unicode ones, and matched this one accordingly.
     Whether a given property matches these code points or not is
     specified in "Properties accessible through \p{} and \P{}" in
     perluniprops.

     This message is suppressed (unless it has been made fatal) if it is
     immaterial to the results of the match if the code point is Unicode
     or not.  For example, the property "\p{ASCII_Hex_Digit}" only can
     match the 22 characters "[0-9A-Fa-f]", so obviously all other code
     points, Unicode or not, won't match it.  (And "\P{ASCII_Hex_Digit}"
     will match every code point except these 22.)

     Getting this message indicates that the outcome of the match arguably
     should have been the opposite of what actually happened.  If you
     think that is the case, you may wish to make the "non_unicode"
     warnings category fatal; if you agree with Perl's decision, you may
     wish to turn off this category.

     See "Beyond Unicode code points" in perlunicode for more information.

 %s matches null string many times in regex; marked by <-- HERE in m/%s/
     (W regexp) The pattern you've specified would be an infinite loop if
     the regular expression engine didn't specifically check for that.
     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Maximal count of pending signals (%u) exceeded
     (F) Perl aborted due to too high a number of signals pending.  This
     usually indicates that your operating system tried to deliver signals
     too fast (with a very high priority), starving the perl process from
     resources it would need to reach a point where it can process signals
     safely.  (See "Deferred Signals (Safe Signals)" in perlipc.)

 "%s" may clash with future reserved word
     (W) This warning may be due to running a perl5 script through a perl4
     interpreter, especially if the word that is being warned about is
     "use" or "my".

 '%' may not be used in pack
     (F) You can't pack a string by supplying a checksum, because the
     checksumming process loses information, and you can't go the other
     way.  See "unpack" in perlfunc.

 Method for operation %s not found in package %s during blessing
     (F) An attempt was made to specify an entry in an overloading table
     that doesn't resolve to a valid subroutine.  See overload.

 Method %s not permitted
     See "500 Server error".

 Might be a runaway multi-line %s string starting on line %d
     (S) An advisory indicating that the previous error may have been
     caused by a missing delimiter on a string or pattern, because it
     eventually ended earlier on the current line.

 Misplaced _ in number
     (W syntax) An underscore (underbar) in a numeric constant did not
     separate two digits.

 Missing argument for %n in %s
     (F) A %n was used in a format string with no corresponding argument
     for perl to write the current string length to.

 Missing argument in %s
     (W missing) You called a function with fewer arguments than other
     arguments you supplied indicated would be needed.

     Currently only emitted when a printf-type format required more
     arguments than were supplied, but might be used in the future for
     other cases where we can statically determine that arguments to
     functions are missing, e.g. for the "pack" in perlfunc function.

 Missing argument to -%c
     (F) The argument to the indicated command line switch must follow
     immediately after the switch, without intervening spaces.

 Missing braces on \N{}
 Missing braces on \N{} in regex; marked by <-- HERE in m/%s/
     (F) Wrong syntax of character name literal "\N{charname}" within
     double-quotish context.  This can also happen when there is a space
     (or comment) between the "\N" and the "{" in a regex with the "/x"
     modifier.  This modifier does not change the requirement that the
     brace immediately follow the "\N".

 Missing braces on \o{}
     (F) A "\o" must be followed immediately by a "{" in double-quotish
     context.

 Missing comma after first argument to %s function
     (F) While certain functions allow you to specify a filehandle or an
     "indirect object" before the argument list, this ain't one of them.

 Missing command in piped open
     (W pipe) You used the "open(FH, "| command")" or "open(FH, "command
     |")" construction, but the command was missing or blank.

 Missing control char name in \c
     (F) A double-quoted string ended with "\c", without the required
     control character name.

 Missing ']' in prototype for %s : %s
     (W illegalproto) A grouping was started with "[" but never closed
     with "]".

 Missing name in "%s sub"
     (F) The syntax for lexically scoped subroutines requires that they
     have a name with which they can be found.

 Missing $ on loop variable
     (F) Apparently you've been programming in ccsshh too much.  Variables
     are always mentioned with the $ in Perl, unlike in the shells, where
     it can vary from one line to the next.

 (Missing operator before %s?)
     (S syntax) This is an educated guess made in conjunction with the
     message "%s found where operator expected".  Often the missing
     operator is a comma.

 Missing or undefined argument to %s
     (F) You tried to call require or do with no argument or with an
     undefined value as an argument.  Require expects either a package
     name or a file-specification as an argument; do expects a filename.
     See "require EXPR" in perlfunc and "do EXPR" in perlfunc.

 Missing right brace on \%c{} in regex; marked by <-- HERE in m/%s/
     (F) Missing right brace in "\x{...}", "\p{...}", "\P{...}", or

“\N{…}”. #

 Missing right brace on \N{}
 Missing right brace on \N{} or unescaped left brace after \N
     (F) "\N" has two meanings.

     The traditional one has it followed by a name enclosed in braces,
     meaning the character (or sequence of characters) given by that name.
     Thus "\N{ASTERISK}" is another way of writing "*", valid in both
     double-quoted strings and regular expression patterns.  In patterns,
     it doesn't have the meaning an unescaped "*" does.

     Starting in Perl 5.12.0, "\N" also can have an additional meaning
     (only) in patterns, namely to match a non-newline character.  (This
     is short for "[^\n]", and like "." but is not affected by the "/s"
     regex modifier.)

     This can lead to some ambiguities.  When "\N" is not followed
     immediately by a left brace, Perl assumes the "[^\n]" meaning.  Also,
     if the braces form a valid quantifier such as "\N{3}" or "\N{5,}",
     Perl assumes that this means to match the given quantity of non-
     newlines (in these examples, 3; and 5 or more, respectively).  In all
     other case, where there is a "\N{" and a matching "}", Perl assumes
     that a character name is desired.

     However, if there is no matching "}", Perl doesn't know if it was
     mistakenly omitted, or if "[^\n]{" was desired, and raises this
     error.  If you meant the former, add the right brace; if you meant
     the latter, escape the brace with a backslash, like so: "\N\{"

 Missing right curly or square bracket
     (F) The lexer counted more opening curly or square brackets than
     closing ones.  As a general rule, you'll find it's missing near the
     place you were last editing.

 (Missing semicolon on previous line?)
     (S syntax) This is an educated guess made in conjunction with the
     message "%s found where operator expected".  Don't automatically put
     a semicolon on the previous line just because you saw this message.

 Modification of a read-only value attempted
     (F) You tried, directly or indirectly, to change the value of a
     constant.  You didn't, of course, try "2 = 1", because the compiler
     catches that.  But an easy way to do the same thing is:

         sub mod { $_[0] = 1 }
         mod(2);

     Another way is to assign to a ssuubbssttrr(()) that's off the end of the
     string.

     Yet another way is to assign to a "foreach" loop _V_A_R when _V_A_R is
     aliased to a constant in the look _L_I_S_T:

         $x = 1;
         foreach my $n ($x, 2) {
             $n *= 2; # modifies the $x, but fails on attempt to
         }            # modify the 2

     PerlIO::scalar will also produce this message as a warning if you
     attempt to open a read-only scalar for writing.

 Modification of non-creatable array value attempted, %s
     (F) You tried to make an array value spring into existence, and the
     subscript was probably negative, even counting from end of the array
     backwards.

 Modification of non-creatable hash value attempted, %s
     (P) You tried to make a hash value spring into existence, and it
     couldn't be created for some peculiar reason.

 Module name must be constant
     (F) Only a bare module name is allowed as the first argument to a
     "use".

 Module name required with -%c option
     (F) The "-M" or "-m" options say that Perl should load some module,
     but you omitted the name of the module.  Consult perlrun for full
     details about "-M" and "-m".

 More than one argument to '%s' open
     (F) The "open" function has been asked to open multiple files.  This
     can happen if you are trying to open a pipe to a command that takes a
     list of arguments, but have forgotten to specify a piped open mode.
     See "open" in perlfunc for details.

 mprotect for COW string %p %u failed with %d
     (S) You compiled perl with --DDPERL_DEBUG_READONLY_COW (see "Copy on
     Write" in perlguts), but a shared string buffer could not be made
     read-only.

 mprotect for %p %u failed with %d
     (S) You compiled perl with --DDPERL_DEBUG_READONLY_OPS (see
     perlhacktips), but an op tree could not be made read-only.

 mprotect RW for COW string %p %u failed with %d
     (S) You compiled perl with --DDPERL_DEBUG_READONLY_COW (see "Copy on
     Write" in perlguts), but a read-only shared string buffer could not
     be made mutable.

 mprotect RW for %p %u failed with %d
     (S) You compiled perl with --DDPERL_DEBUG_READONLY_OPS (see
     perlhacktips), but a read-only op tree could not be made mutable
     before freeing the ops.

 msg%s not implemented
     (F) You don't have System V message IPC on your system.

 Multidimensional hash lookup is disabled
     (F) You supplied a list of subscripts to a hash lookup under "no
     feature "multidimensional";", eg:

       $z = $foo{$x, $y};

     which by default acts like:

       $z = $foo{join($;, $x, $y)};

 Multidimensional syntax %s not supported
     (W syntax) Multidimensional arrays aren't written like $foo[1,2,3].
     They're written like $foo[1][2][3], as in C.

 Multiple slurpy parameters not allowed
     (F) In subroutine signatures, a slurpy parameter ("@" or "%") must be
     the last parameter, and there must not be more than one of them; for
     example:

         sub foo ($a, @b)    {} # legal
         sub foo ($a, @b, %) {} # invalid

 '/' must follow a numeric type in unpack
     (F) You had an unpack template that contained a '/', but this did not
     follow some unpack specification producing a numeric value.  See
     "pack" in perlfunc.

 %s must not be a named sequence in transliteration operator
     (F) Transliteration ("tr///" and "y///") transliterates individual
     characters.  But a named sequence by definition is more than an
     individual character, and hence doing this operation on it doesn't
     make sense.

 "my sub" not yet implemented
     (F) Lexically scoped subroutines are not yet implemented.  Don't try
     that yet.

 "my" subroutine %s can't be in a package
     (F) Lexically scoped subroutines aren't in a package, so it doesn't
     make sense to try to declare one with a package qualifier on the
     front.

 "my %s" used in sort comparison
     (W syntax) The package variables $a and $b are used for sort
     comparisons.  You used $a or $b in as an operand to the "<=>" or
     "cmp" operator inside a sort comparison block, and the variable had
     earlier been declared as a lexical variable.  Either qualify the sort
     variable with the package name, or rename the lexical variable.

 "my" variable %s can't be in a package
     (F) Lexically scoped variables aren't in a package, so it doesn't
     make sense to try to declare one with a package qualifier on the
     front.  Use llooccaall(()) if you want to localize a package variable.

 Name "%s::%s" used only once: possible typo
     (W once) Typographical errors often show up as unique variable names.
     If you had a good reason for having a unique name, then just mention
     it again somehow to suppress the message.  The "our" declaration is
     also provided for this purpose.

     NOTE: This warning detects package symbols that have been used only
     once.  This means lexical variables will never trigger this warning.
     It also means that all of the package variables $c, @c, %c, as well
     as *c, &c, sub c{}, c(), and c (the filehandle or format) are
     considered the same; if a program uses $c only once but also uses any
     of the others it will not trigger this warning.  Symbols beginning
     with an underscore and symbols using special identifiers (q.v.
     perldata) are exempt from this warning.

 Need exactly 3 octal digits in regex; marked by <-- HERE in m/%s/
     (F) Within "(?[   ])", all constants interpreted as octal need to be
     exactly 3 digits long.  This helps catch some ambiguities.  If your
     constant is too short, add leading zeros, like

      (?[ [ \078 ] ])     # Syntax error!
      (?[ [ \0078 ] ])    # Works
      (?[ [ \007 8 ] ])   # Clearer

     The maximum number this construct can express is "\777".  If you need
     a larger one, you need to use \o{} instead.  If you meant two
     separate things, you need to separate them:

      (?[ [ \7776 ] ])        # Syntax error!
      (?[ [ \o{7776} ] ])     # One meaning
      (?[ [ \777 6 ] ])       # Another meaning
      (?[ [ \777 \006 ] ])    # Still another

 Negative '/' count in unpack
     (F) The length count obtained from a length/code unpack operation was
     negative.  See "pack" in perlfunc.

 Negative length
     (F) You tried to do a read/write/send/recv operation with a buffer
     length that is less than 0.  This is difficult to imagine.

 Negative offset to vec in lvalue context
     (F) When "vec" is called in an lvalue context, the second argument
     must be greater than or equal to zero.

 Negative repeat count does nothing
     (W numeric) You tried to execute the "x" repetition operator fewer
     than 0 times, which doesn't make sense.

 Nested quantifiers in regex; marked by <-- HERE in m/%s/
     (F) You can't quantify a quantifier without intervening parentheses.
     So things like ** or +* or ?* are illegal.  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.

     Note that the minimal matching quantifiers, "*?", "+?", and "??"
     appear to be nested quantifiers, but aren't.  See perlre.

 %s never introduced
     (S internal) The symbol in question was declared but somehow went out
     of scope before it could possibly have been used.

 next::method/next::can/maybe::next::method cannot find enclosing method
     (F) "next::method" needs to be called within the context of a real
     method in a real package, and it could not find such a context.  See
     mro.

 \N in a character class must be a named character: \N{...} in regex;
 marked by <-- HERE in m/%s/
     (F) The new (as of Perl 5.12) meaning of "\N" as "[^\n]" is not valid
     in a bracketed character class, for the same reason that "." in a
     character class loses its specialness: it matches almost everything,
     which is probably not what you want.

 \N{} here is restricted to one character in regex; marked by <-- HERE in
 m/%s/
     (F) Named Unicode character escapes ("\N{...}") may return a multi-
     character sequence.  Even though a character class is supposed to
     match just one character of input, perl will match the whole thing
     correctly, except under certain conditions.  These currently are

     When the class is inverted ("[^...]")
         The mathematically logical behavior for what matches when
         inverting is very different from what people expect, so we have
         decided to forbid it.

     The escape is the beginning or final end point of a range
         Similarly unclear is what should be generated when the "\N{...}"
         is used as one of the end points of the range, such as in

          [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]

         What is meant here is unclear, as the "\N{...}" escape is a
         sequence of code points, so this is made an error.

     In a regex set
         The syntax "(?[   ])" in a regular expression yields a list of
         single code points, none can be a sequence.

 No %s allowed while running setuid
     (F) Certain operations are deemed to be too insecure for a setuid or
     setgid script to even be allowed to attempt.  Generally speaking
     there will be another way to do what you want that is, if not secure,
     at least securable.  See perlsec.

 No code specified for -%c
     (F) Perl's --ee and --EE command-line options require an argument.  If
     you want to run an empty program, pass the empty string as a separate
     argument or run a program consisting of a single 0 or 1:

         perl -e ""
         perl -e0
         perl -e1

 No comma allowed after %s
     (F) A list operator that has a filehandle or "indirect object" is not
     allowed to have a comma between that and the following arguments.
     Otherwise it'd be just another one of the arguments.

     One possible cause for this is that you expected to have imported a
     constant to your name space with uussee or iimmppoorrtt while no such
     importing took place, it may for example be that your operating
     system does not support that particular constant.  Hopefully you did
     use an explicit import list for the constants you expect to see;
     please see "use" in perlfunc and "import" in perlfunc.  While an
     explicit import list would probably have caught this error earlier it
     naturally does not remedy the fact that your operating system still
     does not support that constant.  Maybe you have a typo in the
     constants of the symbol import list of uussee or iimmppoorrtt or in the
     constant name at the line where this error was triggered?

 No command into which to pipe on command line
     (F) An error peculiar to VMS.  Perl handles its own command line
     redirection, and found a '|' at the end of the command line, so it
     doesn't know where you want to pipe the output from this command.

 No DB::DB routine defined
     (F) The currently executing code was compiled with the --dd switch, but
     for some reason the current debugger (e.g. _p_e_r_l_5_d_b_._p_l or a "Devel::"
     module) didn't define a routine to be called at the beginning of each
     statement.

 No dbm on this machine
     (P) This is counted as an internal error, because every machine
     should supply dbm nowadays, because Perl comes with SDBM.  See
     SDBM_File.

 No DB::sub routine defined
     (F) The currently executing code was compiled with the --dd switch, but
     for some reason the current debugger (e.g. _p_e_r_l_5_d_b_._p_l or a "Devel::"
     module) didn't define a "DB::sub" routine to be called at the
     beginning of each ordinary subroutine call.

 No digits found for %s literal
     (F) No hexadecimal digits were found following "0x" or no binary
     digits were found following "0b".

 No directory specified for -I
     (F) The --II command-line switch requires a directory name as part of
     the _s_a_m_e argument.  Use --IIlliibb, for instance.  --II lliibb won't work.

 No error file after 2> or 2>> on command line
     (F) An error peculiar to VMS.  Perl handles its own command line
     redirection, and found a '2>' or a '2>>' on the command line, but
     can't find the name of the file to which to write data destined for
     stderr.

 No group ending character '%c' found in template
     (F) A pack or unpack template has an opening '(' or '[' without its
     matching counterpart.  See "pack" in perlfunc.

 No input file after < on command line
     (F) An error peculiar to VMS.  Perl handles its own command line
     redirection, and found a '<' on the command line, but can't find the
     name of the file from which to read data for stdin.

 No next::method '%s' found for %s
     (F) "next::method" found no further instances of this method name in
     the remaining packages of the MRO of this class.  If you don't want
     it throwing an exception, use "maybe::next::method" or "next::can".
     See mro.

 Non-finite repeat count does nothing
     (W numeric) You tried to execute the "x" repetition operator "Inf"
     (or "-Inf") or "NaN" times, which doesn't make sense.

 Non-hex character in regex; marked by <-- HERE in m/%s/
     (F) In a regular expression, there was a non-hexadecimal character
     where a hex one was expected, like

      (?[ [ \xDG ] ])
      (?[ [ \x{DEKA} ] ])

 Non-hex character '%c' terminates \x early.  Resolved as "%s"
     (W digit) In parsing a hexadecimal numeric constant, a character was
     unexpectedly encountered that isn't hexadecimal.  The resulting value
     is as indicated.

     Note that, within braces, every character starting with the first
     non-hexadecimal up to the ending brace is ignored.

 Non-octal character in regex; marked by <-- HERE in m/%s/
     (F) In a regular expression, there was a non-octal character where an
     octal one was expected, like

      (?[ [ \o{1278} ] ])

 Non-octal character '%c' terminates \o early.  Resolved as "%s"
     (W digit) In parsing an octal numeric constant, a character was
     unexpectedly encountered that isn't octal.  The resulting value is as
     indicated.

     When not using "\o{...}", you wrote something like "\08", or "\179"
     in a double-quotish string.  The resolution is as indicated, with all
     but the last digit treated as a single character, specified in octal.
     The last digit is the next character in the string.  To tell Perl
     that this is indeed what you want, you can use the "\o{ }" syntax, or
     use exactly three digits to specify the octal for the character.

     Note that, within braces, every character starting with the first
     non-octal up to the ending brace is ignored.

 "no" not allowed in expression
     (F) The "no" keyword is recognized and executed at compile time, and
     returns no useful value.  See perlmod.

 Non-string passed as bitmask
     (W misc) A number has been passed as a bitmask argument to sseelleecctt(()).
     Use the vveecc(()) function to construct the file descriptor bitmasks for
     select.  See "select" in perlfunc.

 No output file after > on command line
     (F) An error peculiar to VMS.  Perl handles its own command line
     redirection, and found a lone '>' at the end of the command line, so
     it doesn't know where you wanted to redirect stdout.

 No output file after > or >> on command line
     (F) An error peculiar to VMS.  Perl handles its own command line
     redirection, and found a '>' or a '>>' on the command line, but can't
     find the name of the file to which to write data destined for stdout.

 No package name allowed for subroutine %s in "our"
 No package name allowed for variable %s in "our"
     (F) Fully qualified subroutine and variable names are not allowed in
     "our" declarations, because that doesn't make much sense under
     existing rules.  Such syntax is reserved for future extensions.

 No Perl script found in input
     (F) You called "perl -x", but no line was found in the file beginning
     with #! and containing the word "perl".

 No setregid available
     (F) Configure didn't find anything resembling the sseettrreeggiidd(()) call for
     your system.

 No setreuid available
     (F) Configure didn't find anything resembling the sseettrreeuuiidd(()) call for
     your system.

 No such class %s
     (F) You provided a class qualifier in a "my", "our" or "state"
     declaration, but this class doesn't exist at this point in your
     program.

 No such class field "%s" in variable %s of type %s
     (F) You tried to access a key from a hash through the indicated typed
     variable but that key is not allowed by the package of the same type.
     The indicated package has restricted the set of allowed keys using
     the fields pragma.

 No such hook: %s
     (F) You specified a signal hook that was not recognized by Perl.
     Currently, Perl accepts "__DIE__" and "__WARN__" as valid signal
     hooks.

 No such pipe open
     (P) An error peculiar to VMS.  The internal routine mmyy__ppcclloossee(()) tried
     to close a pipe which hadn't been opened.  This should have been
     caught earlier as an attempt to close an unopened filehandle.

 No such signal: SIG%s
     (W signal) You specified a signal name as a subscript to %SIG that
     was not recognized.  Say "kill -l" in your shell to see the valid
     signal names on your system.

 No Unicode property value wildcard matches:
     (W regexp) You specified a wildcard for a Unicode property value, but
     there is no property value in the current Unicode release that
     matches it.  Check your spelling.

 Not a CODE reference
     (F) Perl was trying to evaluate a reference to a code value (that is,
     a subroutine), but found a reference to something else instead.  You
     can use the rreeff(()) function to find out what kind of ref it really
     was.  See also perlref.

 Not a GLOB reference
     (F) Perl was trying to evaluate a reference to a "typeglob" (that is,
     a symbol table entry that looks like *foo), but found a reference to
     something else instead.  You can use the rreeff(()) function to find out
     what kind of ref it really was.  See perlref.

 Not a HASH reference
     (F) Perl was trying to evaluate a reference to a hash value, but
     found a reference to something else instead.  You can use the rreeff(())
     function to find out what kind of ref it really was.  See perlref.

 '#' not allowed immediately following a sigil in a subroutine signature
     (F) In a subroutine signature definition, a comment following a sigil
     ("$", "@" or "%"), needs to be separated by whitespace or a comma
     etc., in particular to avoid confusion with the $# variable.  For
     example:

         # bad
         sub f ($# ignore first arg
                , $b) {}
         # good
         sub f ($, # ignore first arg
                $b) {}

 Not an ARRAY reference
     (F) Perl was trying to evaluate a reference to an array value, but
     found a reference to something else instead.  You can use the rreeff(())
     function to find out what kind of ref it really was.  See perlref.

 Not a SCALAR reference
     (F) Perl was trying to evaluate a reference to a scalar value, but
     found a reference to something else instead.  You can use the rreeff(())
     function to find out what kind of ref it really was.  See perlref.

 Not a subroutine reference
     (F) Perl was trying to evaluate a reference to a code value (that is,
     a subroutine), but found a reference to something else instead.  You
     can use the rreeff(()) function to find out what kind of ref it really
     was.  See also perlref.

 Not a subroutine reference in overload table
     (F) An attempt was made to specify an entry in an overloading table
     that doesn't somehow point to a valid subroutine.  See overload.

 Not enough arguments for %s
     (F) The function requires more arguments than you specified.

 Not enough format arguments
     (W syntax) A format specified more picture fields than the next line
     supplied.  See perlform.

 %s: not found
     (A) You've accidentally run your script through the Bourne shell
     instead of Perl.  Check the #! line, or manually feed your script
     into Perl yourself.

 no UTC offset information; assuming local time is UTC
     (S) A warning peculiar to VMS.  Perl was unable to find the local
     timezone offset, so it's assuming that local system time is
     equivalent to UTC.  If it's not, define the logical name
     _S_Y_S_$_T_I_M_E_Z_O_N_E___D_I_F_F_E_R_E_N_T_I_A_L to translate to the number of seconds which
     need to be added to UTC to get local time.

NULL OP IN RUN #

     (S debugging) Some internal routine called rruunn(()) with a null opcode
     pointer.

 Null picture in formline
     (F) The first argument to formline must be a valid format picture
     specification.  It was found to be empty, which probably means you
     supplied it an uninitialized value.  See perlform.

 NULL regexp parameter
     (P) The internal pattern matching routines are out of their gourd.

 Number too long
     (F) Perl limits the representation of decimal numbers in programs to
     about 250 characters.  You've exceeded that length.  Future versions
     of Perl are likely to eliminate this arbitrary limitation.  In the
     meantime, try using scientific notation (e.g. "1e6" instead of
     "1_000_000").

 Number with no digits
     (F) Perl was looking for a number but found nothing that looked like
     a number.  This happens, for example with "\o{}", with no number
     between the braces.

 Numeric format result too large
     (F) The length of the result of a numeric format supplied to
     sspprriinnttff(()) or pprriinnttff(()) would have been too large for the underlying C
     function to report.  This limit is typically 2GB.

 Numeric variables with more than one digit may not start with '0'
     (F) The only numeric variable which is allowed to start with a 0 is
     $0, and you mentioned a variable that starts with 0 that has more
     than one digit. You probably want to remove the leading 0, or if the
     intent was to express a variable name in octal you should convert to
     decimal.

 Octal number > 037777777777 non-portable
     (W portable) The octal number you specified is larger than 2**32-1
     (4294967295) and therefore non-portable between systems.  See
     perlport for more on portability concerns.

 Odd name/value argument for subroutine '%s'
     (F) A subroutine using a slurpy hash parameter in its signature
     received an odd number of arguments to populate the hash.  It
     requires the arguments to be paired, with the same number of keys as
     values.  The caller of the subroutine is presumably at fault.

     The message attempts to include the name of the called subroutine. If
     the subroutine has been aliased, the subroutine's original name will
     be shown, regardless of what name the caller used.

 Odd number of arguments for overload::constant
     (W overload) The call to overload::constant contained an odd number
     of arguments.  The arguments should come in pairs.

 Odd number of elements in anonymous hash
     (W misc) You specified an odd number of elements to initialize a
     hash, which is odd, because hashes come in key/value pairs.

 Odd number of elements in hash assignment
     (W misc) You specified an odd number of elements to initialize a
     hash, which is odd, because hashes come in key/value pairs.

 Offset outside string
     (F)(W layer) You tried to do a read/write/send/recv/seek operation
     with an offset pointing outside the buffer.  This is difficult to
     imagine.  The sole exceptions to this are that zero padding will take
     place when going past the end of the string when either
     "sysread()"ing a file, or when seeking past the end of a scalar
     opened for I/O (in anticipation of future reads and to imitate the
     behavior with real files).

 Old package separator used in string
     (W syntax) You used the old package separator, "'", in a variable
     named inside a double-quoted string; e.g., "In $name's house".  This
     is equivalent to "In $name::s house".  If you meant the former, put a
     backslash before the apostrophe ("In $name\'s house").

 %s() on unopened %s
     (W unopened) An I/O operation was attempted on a filehandle that was
     never initialized.  You need to do an ooppeenn(()), a ssyyssooppeenn(()), or a
     ssoocckkeett(()) call, or call a constructor from the FileHandle package.

 -%s on unopened filehandle %s
     (W unopened) You tried to invoke a file test operator on a filehandle
     that isn't open.  Check your control flow.  See also "-X" in
     perlfunc.

 oops: oopsAV
     (S internal) An internal warning that the grammar is screwed up.

 oops: oopsHV
     (S internal) An internal warning that the grammar is screwed up.

 Operand with no preceding operator in regex; marked by <-- HERE in m/%s/
     (F) You wrote something like

      (?[ \p{Digit} \p{Thai} ])

     There are two operands, but no operator giving how you want to
     combine them.

 Operation "%s": no method found, %s
     (F) An attempt was made to perform an overloaded operation for which
     no handler was defined.  While some handlers can be autogenerated in
     terms of other handlers, there is no default handler for any
     operation, unless the "fallback" overloading key is specified to be
     true.  See overload.

 Operation "%s" returns its argument for non-Unicode code point 0x%X
     (S non_unicode) You performed an operation requiring Unicode rules on
     a code point that is not in Unicode, so what it should do is not
     defined.  Perl has chosen to have it do nothing, and warn you.

     If the operation shown is "ToFold", it means that case-insensitive
     matching in a regular expression was done on the code point.

     If you know what you are doing you can turn off this warning by "no
     warnings 'non_unicode';".

 Operation "%s" returns its argument for UTF-16 surrogate U+%X
     (S surrogate) You performed an operation requiring Unicode rules on a
     Unicode surrogate.  Unicode frowns upon the use of surrogates for
     anything but storing strings in UTF-16, but rules are (reluctantly)
     defined for the surrogates, and they are to do nothing for this
     operation.  Because the use of surrogates can be dangerous, Perl
     warns.

     If the operation shown is "ToFold", it means that case-insensitive
     matching in a regular expression was done on the code point.

     If you know what you are doing you can turn off this warning by "no
     warnings 'surrogate';".

 Operator or semicolon missing before %s
     (S ambiguous) You used a variable or subroutine call where the parser
     was expecting an operator.  The parser has assumed you really meant
     to use an operator, but this is highly likely to be incorrect.  For
     example, if you say "*foo *foo" it will be interpreted as if you said
     "*foo * 'foo'".

 Optional parameter lacks default expression
     (F) In a subroutine signature, you wrote something like "$a =",
     making a named optional parameter without a default value.  A
     nameless optional parameter is permitted to have no default value,
     but a named one must have a specific default.  You probably want "$a
     = undef".

 "our" variable %s redeclared
     (W shadow) You seem to have already declared the same global once
     before in the current lexical scope.

 Out of memory!
     (X) The mmaalllloocc(()) function returned 0, indicating there was
     insufficient remaining memory (or virtual memory) to satisfy the
     request.  Perl has no option but to exit immediately.

     At least in Unix you may be able to get past this by increasing your
     process datasize limits: in csh/tcsh use "limit" and "limit datasize
     n" (where "n" is the number of kilobytes) to check the current limits
     and change them, and in ksh/bash/zsh use "ulimit -a" and "ulimit -d
     n", respectively.

 Out of memory during %s extend
     (X) An attempt was made to extend an array, a list, or a string
     beyond the largest possible memory allocation.

 Out of memory during "large" request for %s
     (F) The mmaalllloocc(()) function returned 0, indicating there was
     insufficient remaining memory (or virtual memory) to satisfy the
     request.  However, the request was judged large enough (compile-time
     default is 64K), so a possibility to shut down by trapping this error
     is granted.

 Out of memory during request for %s
     (X)(F) The mmaalllloocc(()) function returned 0, indicating there was
     insufficient remaining memory (or virtual memory) to satisfy the
     request.

     The request was judged to be small, so the possibility to trap it
     depends on the way perl was compiled.  By default it is not
     trappable.  However, if compiled for this, Perl may use the contents
     of $^M as an emergency pool after ddiiee(())ing with this message.  In
     this case the error is trappable _o_n_c_e, and the error message will
     include the line and file where the failed request happened.

 Out of memory during ridiculously large request
     (F) You can't allocate more than 2^31+"small amount" bytes.  This
     error is most likely to be caused by a typo in the Perl program.
     e.g., $arr[time] instead of $arr[$time].

 Out of memory for yacc stack
     (F) The yacc parser wanted to grow its stack so it could continue
     parsing, but rreeaalllloocc(()) wouldn't give it more memory, virtual or
     otherwise.

 '.' outside of string in pack
     (F) The argument to a '.' in your template tried to move the working
     position to before the start of the packed string being built.

 '@' outside of string in unpack
     (F) You had a template that specified an absolute position outside
     the string being unpacked.  See "pack" in perlfunc.

 '@' outside of string with malformed UTF-8 in unpack
     (F) You had a template that specified an absolute position outside
     the string being unpacked.  The string being unpacked was also
     invalid UTF-8.  See "pack" in perlfunc.

 overload arg '%s' is invalid
     (W overload) The overload pragma was passed an argument it did not
     recognize.  Did you mistype an operator?

 Overloaded dereference did not return a reference
     (F) An object with an overloaded dereference operator was
     dereferenced, but the overloaded operation did not return a
     reference.  See overload.

 Overloaded qr did not return a REGEXP
     (F) An object with a "qr" overload was used as part of a match, but
     the overloaded operation didn't return a compiled regexp.  See
     overload.

 %s package attribute may clash with future reserved word: %s
     (W reserved) A lowercase attribute name was used that had a package-
     specific handler.  That name might have a meaning to Perl itself some
     day, even though it doesn't yet.  Perhaps you should use a mixed-case
     attribute name, instead.  See attributes.

 pack/unpack repeat count overflow
     (F) You can't specify a repeat count so large that it overflows your
     signed integers.  See "pack" in perlfunc.

 page overflow
     (W io) A single call to wwrriittee(()) produced more lines than can fit on a
     page.  See perlform.

 panic: %s
     (P) An internal error.

 panic: attempt to call %s in %s
     (P) One of the file test operators entered a code branch that calls
     an ACL related-function, but that function is not available on this
     platform.  Earlier checks mean that it should not be possible to
     enter this branch on this platform.

 panic: child pseudo-process was never scheduled
     (P) A child pseudo-process in the ithreads implementation on Windows
     was not scheduled within the time period allowed and therefore was
     not able to initialize properly.

 panic: ck_grep, type=%u
     (P) Failed an internal consistency check trying to compile a grep.

 panic: corrupt saved stack index %ld
     (P) The savestack was requested to restore more localized values than
     there are in the savestack.

 panic: del_backref
     (P) Failed an internal consistency check while trying to reset a weak
     reference.

 panic: fold_constants JMPENV_PUSH returned %d
     (P) While attempting folding constants an exception other than an
     "eval" failure was caught.

 panic: frexp: %f
     (P) The library function ffrreexxpp(()) failed, making printf("%f")
     impossible.

 panic: goto, type=%u, ix=%ld
     (P) We popped the context stack to a context with the specified
     label, and then discovered it wasn't a context we know how to do a
     goto in.

 panic: gp_free failed to free glob pointer
     (P) The internal routine used to clear a typeglob's entries tried
     repeatedly, but each time something re-created entries in the glob.
     Most likely the glob contains an object with a reference back to the
     glob and a destructor that adds a new object to the glob.

 panic: INTERPCASEMOD, %s
     (P) The lexer got into a bad state at a case modifier.

 panic: INTERPCONCAT, %s
     (P) The lexer got into a bad state parsing a string with brackets.

 panic: kid popen errno read
     (F) A forked child returned an incomprehensible message about its
     errno.

 panic: leave_scope inconsistency %u
     (P) The savestack probably got out of sync.  At least, there was an
     invalid enum on the top of it.

 panic: magic_killbackrefs
     (P) Failed an internal consistency check while trying to reset all
     weak references to an object.

 panic: malloc, %s
     (P) Something requested a negative number of bytes of malloc.

 panic: memory wrap
     (P) Something tried to allocate either more memory than possible or a
     negative amount.

 panic: newFORLOOP, %s
     (P) The parser failed an internal consistency check while trying to
     parse a "foreach" loop.

 panic: pad_alloc, %p!=%p
     (P) The compiler got confused about which scratch pad it was
     allocating and freeing temporaries and lexicals from.

 panic: pad_free curpad, %p!=%p
     (P) The compiler got confused about which scratch pad it was
     allocating and freeing temporaries and lexicals from.

 panic: pad_free po
     (P) A zero scratch pad offset was detected internally.  An attempt
     was made to free a target that had not been allocated to begin with.

 panic: pad_reset curpad, %p!=%p
     (P) The compiler got confused about which scratch pad it was
     allocating and freeing temporaries and lexicals from.

 panic: pad_sv po
     (P) A zero scratch pad offset was detected internally.  Most likely
     an operator needed a target but that target had not been allocated
     for whatever reason.

 panic: pad_swipe curpad, %p!=%p
     (P) The compiler got confused about which scratch pad it was
     allocating and freeing temporaries and lexicals from.

 panic: pad_swipe po
     (P) An invalid scratch pad offset was detected internally.

 panic: pp_iter, type=%u
     (P) The foreach iterator got called in a non-loop context frame.

 panic: pp_match%s
     (P) The internal pppp__mmaattcchh(()) routine was called with invalid
     operational data.

 panic: realloc, %s
     (P) Something requested a negative number of bytes of realloc.

 panic: reference miscount on nsv in ssvv__rreeppllaaccee(()) (%d != 1)
     (P) The internal ssvv__rreeppllaaccee(()) function was handed a new SV with a
     reference count other than 1.

 panic: restartop in %s
     (P) Some internal routine requested a goto (or something like it),
     and didn't supply the destination.

 panic: return, type=%u
     (P) We popped the context stack to a subroutine or eval context, and
     then discovered it wasn't a subroutine or eval context.

 panic: scan_num, %s
     (P) ssccaann__nnuumm(()) got called on something that wasn't a number.

 panic: Sequence (?{...}): no code block found in regex m/%s/
     (P) While compiling a pattern that has embedded (?{}) or (??{}) code
     blocks, perl couldn't locate the code block that should have already
     been seen and compiled by perl before control passed to the regex
     compiler.

 panic: sv_chop %s
     (P) The ssvv__cchhoopp(()) routine was passed a position that is not within
     the scalar's string buffer.

 panic: sv_insert, midend=%p, bigend=%p
     (P) The ssvv__iinnsseerrtt(()) routine was told to remove more string than there
     was string.

 panic: top_env
     (P) The compiler attempted to do a goto, or something weird like
     that.

 panic: unexpected constant lvalue entersub entry via type/targ %d:%d
     (P) When compiling a subroutine call in lvalue context, Perl failed
     an internal consistency check.  It encountered a malformed op tree.

 panic: unimplemented op %s (#%d) called
     (P) The compiler is screwed up and attempted to use an op that isn't
     permitted at run time.

 panic: unknown OA_*: %x
     (P) The internal routine that handles arguments to "&CORE::foo()"
     subroutine calls was unable to determine what type of arguments were
     expected.

 panic: utf16_to_utf8: odd bytelen
     (P) Something tried to call utf16_to_utf8 with an odd (as opposed to
     even) byte length.

 panic: utf16_to_utf8_reversed: odd bytelen
     (P) Something tried to call utf16_to_utf8_reversed with an odd (as
     opposed to even) byte length.

 panic: yylex, %s
     (P) The lexer got into a bad state while processing a case modifier.

 Parentheses missing around "%s" list
     (W parenthesis) You said something like

         my $foo, $bar = @_;

     when you meant

         my ($foo, $bar) = @_;

     Remember that "my", "our", "local" and "state" bind tighter than
     comma.

 Parsing code internal error (%s)
     (F) Parsing code supplied by an extension violated the parser's API
     in a detectable way.

 Pattern subroutine nesting without pos change exceeded limit in regex
     (F) You used a pattern that uses too many nested subpattern calls
     without consuming any text.  Restructure the pattern so text is
     consumed before the nesting limit is exceeded.

 "-p" destination: %s
     (F) An error occurred during the implicit output invoked by the "-p"
     command-line switch.  (This output goes to STDOUT unless you've
     redirected it with sseelleecctt(()).)

 Perl API version %s of %s does not match %s
     (F) The XS module in question was compiled against a different
     incompatible version of Perl than the one that has loaded the XS
     module.

 Perl folding rules are not up-to-date for 0x%X; please use the perlbug
 utility to report; in regex; marked by <-- HERE in m/%s/
     (S regexp) You used a regular expression with case-insensitive
     matching, and there is a bug in Perl in which the built-in regular
     expression folding rules are not accurate.  This may lead to
     incorrect results.  Please report this as a bug to
     <https://github.com/Perl/perl5/issues>.

 Perl_my_%s() not available
     (F) Your platform has very uncommon byte-order and integer size, so
     it was not possible to set up some or all fixed-width byte-order
     conversion functions.  This is only a problem when you're using the
     '<' or '>' modifiers in (un)pack templates.  See "pack" in perlfunc.

 Perl %s required (did you mean %s?)--this is only %s, stopped
     (F) The code you are trying to run has asked for a newer version of
     Perl than you are running.  Perhaps "use 5.10" was written instead of
     "use 5.010" or "use v5.10".  Without the leading "v", the number is
     interpreted as a decimal, with every three digits after the decimal
     point representing a part of the version number.  So 5.10 is
     equivalent to v5.100.

 Perl %s required--this is only %s, stopped
     (F) The module in question uses features of a version of Perl more
     recent than the currently running version.  How long has it been
     since you upgraded, anyway?  See "require" in perlfunc.

 PERL_SH_DIR too long
     (F) An error peculiar to OS/2.  PERL_SH_DIR is the directory to find
     the "sh"-shell in.  See "PERL_SH_DIR" in perlos2.

 PERL_SIGNALS illegal: "%s"
     (X) See "PERL_SIGNALS" in perlrun for legal values.

 Perls since %s too modern--this is %s, stopped
     (F) The code you are trying to run claims it will not run on the
     version of Perl you are using because it is too new.  Maybe the code
     needs to be updated, or maybe it is simply wrong and the version
     check should just be removed.

 perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only
 partially set
     (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
     contained a non hex character.  This could mean you are not using the
     hash seed you think you are.

 perl: warning: Setting locale failed.
     (S) The whole warning message will look something like:

             perl: warning: Setting locale failed.
             perl: warning: Please check that your locale settings:
                     LC_ALL = "En_US",
                     LANG = (unset)
                 are supported and installed on your system.
             perl: warning: Falling back to the standard locale ("C").

     Exactly what were the failed locale settings varies.  In the above
     the settings were that the LC_ALL was "En_US" and the LANG had no
     value.  This error means that Perl detected that you and/or your
     operating system supplier and/or system administrator have set up the
     so-called locale system but Perl could not use those settings.  This
     was not dead serious, fortunately: there is a "default locale" called
     "C" that Perl can and will use, and the script will be run.  Before
     you really fix the problem, however, you will get the same error
     message each time you run Perl.  How to really fix the problem can be
     found in perllocale section LLOOCCAALLEE PPRROOBBLLEEMMSS.

 perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
     (S) Perl was run with the environment variable PERL_PERTURB_KEYS
     defined but containing an unexpected value.  The legal values of this
     setting are as follows.

       Numeric | String        | Result
       --------+---------------+-----------------------------------------
       0       | NO            | Disables key traversal randomization
       1       | RANDOM        | Enables full key traversal randomization
       2       | DETERMINISTIC | Enables repeatable key traversal
               |               | randomization

     Both numeric and string values are accepted, but note that string
     values are case sensitive.  The default for this setting is "RANDOM"
     or 1.

 pid %x not a child
     (W exec) A warning peculiar to VMS.  WWaaiittppiidd(()) was asked to wait for
     a process which isn't a subprocess of the current process.  While
     this is fine from VMS' perspective, it's probably not what you
     intended.

 'P' must have an explicit size in unpack
     (F) The unpack format P must have an explicit size, not "*".

 POSIX class [:%s:] unknown in regex; marked by <-- HERE in m/%s/
     (F) The class in the character class [: :] syntax is unknown.  The
     <-- HERE shows whereabouts in the regular expression the problem was
     discovered.  Note that the POSIX character classes do nnoott have the
     "is" prefix the corresponding C interfaces have: in other words, it's
     "[[:print:]]", not "isprint".  See perlre.

 POSIX getpgrp can't take an argument
     (F) Your system has POSIX ggeettppggrrpp(()), which takes no argument, unlike
     the BSD version, which takes a pid.

 POSIX syntax [%c %c] belongs inside character classes%s in regex; marked
 by <-- HERE in m/%s/
     (W regexp) Perl thinks that you intended to write a POSIX character
     class, but didn't use enough brackets.  These POSIX class constructs
     [: :], [= =], and [. .]  go _i_n_s_i_d_e character classes, the [] are part
     of the construct, for example: "qr/[012[:alpha:]345]/".  What the
     regular expression pattern compiled to is probably not what you were
     intending.  For example, "qr/[:alpha:]/" compiles to a regular
     bracketed character class consisting of the four characters ":",
     "a",  "l", "h", and "p".  To specify the POSIX class, it should have
     been written "qr/[[:alpha:]]/".

     Note that [= =] and [. .] are not currently implemented; they are
     simply placeholders for future extensions and will cause fatal
     errors.  The <-- HERE shows whereabouts in the regular expression the
     problem was discovered.  See perlre.

     If the specification of the class was not completely valid, the
     message indicates that.

 POSIX syntax [. .] is reserved for future extensions in regex; marked by
 <-- HERE in m/%s/
     (F) Within regular expression character classes ([]) the syntax
     beginning with "[." and ending with ".]" is reserved for future
     extensions.  If you need to represent those character sequences
     inside a regular expression character class, just quote the square
     brackets with the backslash: "\[." and ".\]".  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.
     See perlre.

 POSIX syntax [= =] is reserved for future extensions in regex; marked by
 <-- HERE in m/%s/
     (F) Within regular expression character classes ([]) the syntax
     beginning with "[=" and ending with "=]" is reserved for future
     extensions.  If you need to represent those character sequences
     inside a regular expression character class, just quote the square
     brackets with the backslash: "\[=" and "=\]".  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.
     See perlre.

 Possible attempt to put comments in qqww(()) list
     (W qw) qqww(()) lists contain items separated by whitespace; as with
     literal strings, comment characters are not ignored, but are instead
     treated as literal data.  (You may have used different delimiters
     than the parentheses shown here; braces are also frequently used.)

     You probably wrote something like this:

         @list = qw(
             a # a comment
             b # another comment
         );

     when you should have written this:

         @list = qw(
             a
             b
         );

     If you really want comments, build your list the old-fashioned way,
     with quotes and commas:

         @list = (
             'a',    # a comment
             'b',    # another comment
         );

 Possible attempt to separate words with commas
     (W qw) qqww(()) lists contain items separated by whitespace; therefore
     commas aren't needed to separate the items.  (You may have used
     different delimiters than the parentheses shown here; braces are also
     frequently used.)

     You probably wrote something like this:

         qw! a, b, c !;

     which puts literal commas into some of the list items.  Write it
     without commas if you don't want them to appear in your data:

         qw! a b c !;

 Possible memory corruption: %s overflowed 3rd argument
     (F) An iiooccttll(()) or ffccnnttll(()) returned more than Perl was bargaining for.
     Perl guesses a reasonable buffer size, but puts a sentinel byte at
     the end of the buffer just in case.  This sentinel byte got
     clobbered, and Perl assumes that memory is now corrupted.  See
     "ioctl" in perlfunc.

 Possible precedence issue with control flow operator
     (W syntax) There is a possible problem with the mixing of a control
     flow operator (e.g. "return") and a low-precedence operator like
     "or".  Consider:

         sub { return $a or $b; }

     This is parsed as:

         sub { (return $a) or $b; }

     Which is effectively just:

         sub { return $a; }

     Either use parentheses or the high-precedence variant of the
     operator.

     Note this may be also triggered for constructs like:

         sub { 1 if die; }

 Possible precedence problem on bitwise %s operator
     (W precedence) Your program uses a bitwise logical operator in
     conjunction with a numeric comparison operator, like this :

         if ($x & $y == 0) { ... }

     This expression is actually equivalent to "$x & ($y == 0)", due to
     the higher precedence of "==".  This is probably not what you want.
     (If you really meant to write this, disable the warning, or, better,
     put the parentheses explicitly and write "$x & ($y == 0)").

 Possible unintended interpolation of $\ in regex
     (W ambiguous) You said something like "m/$\/" in a regex.  The regex
     "m/foo$\s+bar/m" translates to: match the word 'foo', the output
     record separator (see "$\" in perlvar) and the letter 's' (one time
     or more) followed by the word 'bar'.

     If this is what you intended then you can silence the warning by
     using "m/${\}/" (for example: "m/foo${\}s+bar/").

     If instead you intended to match the word 'foo' at the end of the
     line followed by whitespace and the word 'bar' on the next line then
     you can use "m/$(?)\/" (for example: "m/foo$(?)\s+bar/").

 Possible unintended interpolation of %s in string
     (W ambiguous) You said something like '@foo' in a double-quoted
     string but there was no array @foo in scope at the time.  If you
     wanted a literal @foo, then write it as \@foo; otherwise find out
     what happened to the array you apparently lost track of.

 Precedence problem: open %s should be open(%s)
     (S precedence) The old irregular construct

         open FOO || die;

     is now misinterpreted as

         open(FOO || die);

     because of the strict regularization of Perl 5's grammar into unary
     and list operators.  (The old open was a little of both.)  You must
     put parentheses around the filehandle, or use the new "or" operator
     instead of "||".

 Premature end of script headers
     See "500 Server error".

 pprriinnttff(()) on closed filehandle %s
     (W closed) The filehandle you're writing to got itself closed
     sometime before now.  Check your control flow.

 pprriinntt(()) on closed filehandle %s
     (W closed) The filehandle you're printing on got itself closed
     sometime before now.  Check your control flow.

 Process terminated by SIG%s
     (W) This is a standard message issued by OS/2 applications, while
     *nix applications die in silence.  It is considered a feature of the
     OS/2 port.  One can easily disable this by appropriate sighandlers,
     see "Signals" in perlipc.  See also "Process terminated by
     SIGTERM/SIGINT" in perlos2.

 Prototype after '%c' for %s : %s
     (W illegalproto) A character follows % or @ in a prototype.  This is
     useless, since % and @ gobble the rest of the subroutine arguments.

 Prototype mismatch: %s vs %s
     (S prototype) The subroutine being declared or defined had previously
     been declared or defined with a different function prototype.

 Prototype not terminated
     (F) You've omitted the closing parenthesis in a function prototype
     definition.

 Prototype '%s' overridden by attribute 'prototype(%s)' in %s
     (W prototype) A prototype was declared in both the parentheses after
     the sub name and via the prototype attribute.  The prototype in
     parentheses is useless, since it will be replaced by the prototype
     from the attribute before it's ever used.

 Quantifier follows nothing in regex; marked by <-- HERE in m/%s/
     (F) You started a regular expression with a quantifier.  Backslash it
     if you meant it literally.  The <-- HERE shows whereabouts in the
     regular expression the problem was discovered.  See perlre.

 Quantifier in {,} bigger than %d in regex; marked by <-- HERE in m/%s/
     (F) There is currently a limit to the size of the min and max values
     of the {min,max} construct.  The <-- HERE shows whereabouts in the
     regular expression the problem was discovered.  See perlre.

 Quantifier {n,m} with n > m can't match in regex
 Quantifier {n,m} with n > m can't match in regex; marked by <-- HERE in
 m/%s/
     (W regexp) Minima should be less than or equal to maxima.  If you
     really want your regexp to match something 0 times, just put {0}.

 Quantifier unexpected on zero-length expression in regex m/%s/
     (W regexp) You applied a regular expression quantifier in a place
     where it makes no sense, such as on a zero-width assertion.  Try
     putting the quantifier inside the assertion instead.  For example,
     the way to match "abc" provided that it is followed by three
     repetitions of "xyz" is "/abc(?=(?:xyz){3})/", not "/abc(?=xyz){3}/".

 Range iterator outside integer range
     (F) One (or both) of the numeric arguments to the range operator ".."
     are outside the range which can be represented by integers
     internally.  One possible workaround is to force Perl to use magical
     string increment by prepending "0" to your numbers.

 Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
 "a-z" in regex; marked by <-- HERE in m/%s/
     (W regexp) (only under "use re 'strict'" or within "(?[...])")

     Stricter rules help to find typos and other errors.  Perhaps you
     didn't even intend a range here, if the "-" was meant to be some
     other character, or should have been escaped (like "\-").  If you did
     intend a range, the one that was used is not portable between ASCII
     and EBCDIC platforms, and doesn't have an obvious meaning to a casual
     reader.

      [3-7]    # OK; Obvious and portable
      [d-g]    # OK; Obvious and portable
      [A-Y]    # OK; Obvious and portable
      [A-z]    # WRONG; Not portable; not clear what is meant
      [a-Z]    # WRONG; Not portable; not clear what is meant
      [%-.]    # WRONG; Not portable; not clear what is meant
      [\x41-Z] # WRONG; Not portable; not obvious to non-geek

     (You can force portability by specifying a Unicode range, which means
     that the endpoints are specified by "\N{...}", but the meaning may
     still not be obvious.)  The stricter rules require that ranges that
     start or stop with an ASCII character that is not a control have all
     their endpoints be the literal character, and not some escape
     sequence (like "\x41"), and the ranges must be all digits, or all
     uppercase letters, or all lowercase letters.

 Ranges of digits should be from the same group in regex; marked by
 <-- HERE in m/%s/
     (W regexp) (only under "use re 'strict'" or within "(?[...])")

     Stricter rules help to find typos and other errors.  You included a
     range, and at least one of the end points is a decimal digit.  Under
     the stricter rules, when this happens, both end points should be
     digits in the same group of 10 consecutive digits.

 rreeaaddddiirr(()) attempted on invalid dirhandle %s
     (W io) The dirhandle you're reading from is either closed or not
     really a dirhandle.  Check your control flow.

 rreeaaddlliinnee(()) on closed filehandle %s
     (W closed) The filehandle you're reading from got itself closed
     sometime before now.  Check your control flow.

 rreeaaddlliinnee(()) on unopened filehandle %s
     (W unopened) The filehandle you're reading from was never opened.
     Check your control flow.

 rreeaadd(()) on closed filehandle %s
     (W closed) You tried to read from a closed filehandle.

 rreeaadd(()) on unopened filehandle %s
     (W unopened) You tried to read from a filehandle that was never
     opened.

 rreeaalllloocc(()) of freed memory ignored
     (S malloc) An internal routine called rreeaalllloocc(()) on something that had
     already been freed.

 Recompile perl with --DDDEBUGGING to use --DD switch
     (S debugging) You can't use the --DD option unless the code to produce
     the desired output is compiled into Perl, which entails some
     overhead, which is why it's currently left out of your copy.

 Recursive call to Perl_load_module in PerlIO_find_layer
     (P) It is currently not permitted to load modules when creating a
     filehandle inside an %INC hook.  This can happen with "open my $fh,
     '<', \$scalar", which implicitly loads PerlIO::scalar.  Try loading
     PerlIO::scalar explicitly first.

 Recursive inheritance detected in package '%s'
     (F) While calculating the method resolution order (MRO) of a package,
     Perl believes it found an infinite loop in the @ISA hierarchy.  This
     is a crude check that bails out after 100 levels of @ISA depth.

 Redundant argument in %s
     (W redundant) You called a function with more arguments than other
     arguments you supplied indicated would be needed.  Currently only
     emitted when a printf-type format required fewer arguments than were
     supplied, but might be used in the future for e.g. "pack" in
     perlfunc.

 refcnt_dec: fd %d%s
 refcnt: fd %d%s
 refcnt_inc: fd %d%s
     (P) Perl's I/O implementation failed an internal consistency check.
     If you see this message, something is very wrong.

 Reference found where even-sized list expected
     (W misc) You gave a single reference where Perl was expecting a list
     with an even number of elements (for assignment to a hash).  This
     usually means that you used the anon hash constructor when you meant
     to use parens.  In any case, a hash requires key/value ppaaiirrss.

         %hash = { one => 1, two => 2, };    # WRONG
         %hash = [ qw/ an anon array / ];    # WRONG
         %hash = ( one => 1, two => 2, );    # right
         %hash = qw( one 1 two 2 );                  # also fine

 Reference is already weak
     (W misc) You have attempted to weaken a reference that is already
     weak.  Doing so has no effect.

 Reference is not weak
     (W misc) You have attempted to unweaken a reference that is not weak.
     Doing so has no effect.

 Reference to invalid group 0 in regex; marked by <-- HERE in m/%s/
     (F) You used "\g0" or similar in a regular expression.  You may refer
     to capturing parentheses only with strictly positive integers (normal
     backreferences) or with strictly negative integers (relative
     backreferences).  Using 0 does not make sense.

 Reference to nonexistent group in regex; marked by <-- HERE in m/%s/
     (F) You used something like "\7" in your regular expression, but
     there are not at least seven sets of capturing parentheses in the
     expression.  If you wanted to have the character with ordinal 7
     inserted into the regular expression, prepend zeroes to make it three
     digits long: "\007"

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 Reference to nonexistent named group in regex; marked by <-- HERE in
 m/%s/
     (F) You used something like "\k'NAME'" or "\k<NAME>" in your regular
     expression, but there is no corresponding named capturing parentheses
     such as "(?'NAME'...)" or "(?<NAME>...)".  Check if the name has been
     spelled correctly both in the backreference and the declaration.

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 Reference to nonexistent or unclosed group in regex; marked by <-- HERE
 in m/%s/
     (F) You used something like "\g{-7}" in your regular expression, but
     there are not at least seven sets of closed capturing parentheses in
     the expression before where the "\g{-7}" was located.

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 regexp memory corruption
     (P) The regular expression engine got confused by what the regular
     expression compiler gave it.

 Regexp modifier "/%c" may appear a maximum of twice
 Regexp modifier "%c" may appear a maximum of twice in regex; marked by
 <-- HERE in m/%s/
     (F) The regular expression pattern had too many occurrences of the
     specified modifier.  Remove the extraneous ones.

 Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
 HERE in m/%s/
     (F) Turning off the given modifier has the side effect of turning on
     another one.  Perl currently doesn't allow this.  Reword the regular
     expression to use the modifier you want to turn on (and place it
     before the minus), instead of the one you want to turn off.

 Regexp modifier "/%c" may not appear twice
 Regexp modifier "%c" may not appear twice in regex; marked by <-- HERE in
 m/%s/
     (F) The regular expression pattern had too many occurrences of the
     specified modifier.  Remove the extraneous ones.

 Regexp modifiers "/%c" and "/%c" are mutually exclusive
 Regexp modifiers "%c" and "%c" are mutually exclusive in regex; marked by
 <-- HERE in m/%s/
     (F) The regular expression pattern had more than one of these
     mutually exclusive modifiers.  Retain only the modifier that is
     supposed to be there.

 Regexp out of space in regex m/%s/
     (P) A "can't happen" error, because ssaaffeemmaalllloocc(()) should have caught
     it earlier.

 Repeated format line will never terminate (~~ and @#)
     (F) Your format contains the ~~ repeat-until-blank sequence and a
     numeric field that will never go blank so that the repetition never
     terminates.  You might use ^# instead.  See perlform.

 Replacement list is longer than search list
     (W misc) You have used a replacement list that is longer than the
     search list.  So the additional elements in the replacement list are
     meaningless.

 '(*%s' requires a terminating ':' in regex; marked by <-- HERE in m/%s/
     (F) You used a construct that needs a colon and pattern argument.
     Supply these or check that you are using the right construct.

 '%s' resolved to '\o{%s}%d'
     As of Perl 5.32, this message is no longer generated.  Instead, see
     "Non-octal character '%c' terminates \o early.  Resolved as "%s"".
     (W misc, regexp)  You wrote something like "\08", or "\179" in a
     double-quotish string.  All but the last digit is treated as a single
     character, specified in octal.  The last digit is the next character
     in the string.  To tell Perl that this is indeed what you want, you
     can use the "\o{ }" syntax, or use exactly three digits to specify
     the octal for the character.

 Reversed %s= operator
     (W syntax) You wrote your assignment operator backwards.  The = must
     always come last, to avoid ambiguity with subsequent unary operators.

 rreewwiinnddddiirr(()) attempted on invalid dirhandle %s
     (W io) The dirhandle you tried to do a rreewwiinnddddiirr(()) on is either
     closed or not really a dirhandle.  Check your control flow.

 Scalars leaked: %d
     (S internal) Something went wrong in Perl's internal bookkeeping of
     scalars: not all scalar variables were deallocated by the time Perl
     exited.  What this usually indicates is a memory leak, which is of
     course bad, especially if the Perl program is intended to be long-
     running.

 Scalar value @%s[%s] better written as $%s[%s]
     (W syntax) You've used an array slice (indicated by @) to select a
     single element of an array.  Generally it's better to ask for a
     scalar value (indicated by $).  The difference is that $foo[&bar]
     always behaves like a scalar, both when assigning to it and when
     evaluating its argument, while @foo[&bar] behaves like a list when
     you assign to it, and provides a list context to its subscript, which
     can do weird things if you're expecting only one subscript.

     On the other hand, if you were actually hoping to treat the array
     element as a list, you need to look into how references work, because
     Perl will not magically convert between scalars and lists for you.
     See perlref.

 Scalar value @%s{%s} better written as $%s{%s}
     (W syntax) You've used a hash slice (indicated by @) to select a
     single element of a hash.  Generally it's better to ask for a scalar
     value (indicated by $).  The difference is that $foo{&bar} always
     behaves like a scalar, both when assigning to it and when evaluating
     its argument, while @foo{&bar} behaves like a list when you assign to
     it, and provides a list context to its subscript, which can do weird
     things if you're expecting only one subscript.

     On the other hand, if you were actually hoping to treat the hash
     element as a list, you need to look into how references work, because
     Perl will not magically convert between scalars and lists for you.
     See perlref.

 Search pattern not terminated
     (F) The lexer couldn't find the final delimiter of a // or m{}
     construct.  Remember that bracketing delimiters count nesting level.
     Missing the leading "$" from a variable $m may cause this error.

     Note that since Perl 5.10.0 a // can also be the _d_e_f_i_n_e_d_-_o_r
     construct, not just the empty search pattern.  Therefore code written
     in Perl 5.10.0 or later that uses the // as the _d_e_f_i_n_e_d_-_o_r can be
     misparsed by pre-5.10.0 Perls as a non-terminated search pattern.

 sseeeekkddiirr(()) attempted on invalid dirhandle %s
     (W io) The dirhandle you are doing a sseeeekkddiirr(()) on is either closed or
     not really a dirhandle.  Check your control flow.

 %sssseeeekk(()) on unopened filehandle
     (W unopened) You tried to use the sseeeekk(()) or ssyysssseeeekk(()) function on a
     filehandle that was either never opened or has since been closed.

 select not implemented
     (F) This machine doesn't implement the sseelleecctt(()) system call.

 Self-ties of arrays and hashes are not supported
     (F) Self-ties are of arrays and hashes are not supported in the
     current implementation.

 Semicolon seems to be missing
     (W semicolon) A nearby syntax error was probably caused by a missing
     semicolon, or possibly some other missing operator, such as a comma.

 semi-panic: attempt to dup freed string
     (S internal) The internal nneewwSSVVssvv(()) routine was called to duplicate a
     scalar that had previously been marked as free.

 sem%s not implemented
     (F) You don't have System V semaphore IPC on your system.

 sseenndd(()) on closed socket %s
     (W closed) The socket you're sending to got itself closed sometime
     before now.  Check your control flow.

 Sequence "\c{" invalid
     (F) These three characters may not appear in sequence in a double-
     quotish context.  This message is raised only on non-ASCII platforms
     (a different error message is output on ASCII ones).  If you were
     intending to specify a control character with this sequence, you'll
     have to use a different way to specify it.

 Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
     (F) A regular expression ended with an incomplete extension (?.  The
     <-- HERE shows whereabouts in the regular expression the problem was
     discovered.  See perlre.

 Sequence (?%c...) not implemented in regex; marked by <-- HERE in m/%s/
     (F) A proposed regular expression extension has the character
     reserved but has not yet been written.  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.
     See perlre.

 Sequence (?%s...) not recognized in regex; marked by <-- HERE in m/%s/
     (F) You used a regular expression extension that doesn't make sense.
     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  This may happen when using the "(?^...)" construct
     to tell Perl to use the default regular expression modifiers, and you
     redundantly specify a default modifier.  For other causes, see
     perlre.

 Sequence (?#... not terminated in regex m/%s/
     (F) A regular expression comment must be terminated by a closing
     parenthesis.  Embedded parentheses aren't allowed.  See perlre.

 Sequence (?&... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named reference of the form "(?&...)" was missing the final
     closing parenthesis after the name.  The <-- HERE shows whereabouts
     in the regular expression the problem was discovered.

 Sequence (?%c... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named group of the form "(?'...')" or "(?<...>)" was missing
     the final closing quote or angle bracket.  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.

 Sequence (%s... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A lookahead assertion "(?=...)" or "(?!...)" or lookbehind
     assertion "(?<=...)" or "(?<!...)" was missing the final closing
     parenthesis.  The <-- HERE shows whereabouts in the regular
     expression the problem was discovered.

 Sequence (?(%c... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named reference of the form "(?('...')...)" or "(?(<...>)...)"
     was missing the final closing quote or angle bracket after the name.
     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.

 Sequence (?... not terminated in regex; marked by <-- HERE in m/%s/
     (F) There was no matching closing parenthesis for the '('.  The
     <-- HERE shows whereabouts in the regular expression the problem was
     discovered.

 Sequence \%s... not terminated in regex; marked by <-- HERE in m/%s/
     (F) The regular expression expects a mandatory argument following the
     escape sequence and this has been omitted or incorrectly written.

 Sequence (?{...}) not terminated with ')'
     (F) The end of the perl code contained within the {...} must be
     followed immediately by a ')'.

 Sequence (?P>... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named reference of the form "(?P>...)" was missing the final
     closing parenthesis after the name.  The <-- HERE shows whereabouts
     in the regular expression the problem was discovered.

 Sequence (?P<... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named group of the form "(?P<...>')" was missing the final
     closing angle bracket.  The <-- HERE shows whereabouts in the regular
     expression the problem was discovered.

 Sequence ?P=... not terminated in regex; marked by <-- HERE in m/%s/
     (F) A named reference of the form "(?P=...)" was missing the final
     closing parenthesis after the name.  The <-- HERE shows whereabouts
     in the regular expression the problem was discovered.

 Sequence (?R) not terminated in regex m/%s/
     (F) An "(?R)" or "(?0)" sequence in a regular expression was missing
     the final parenthesis.

 500 Server error
     (A) This is the error message generally seen in a browser window when
     trying to run a CGI program (including SSI) over the web.  The actual
     error text varies widely from server to server.  The most frequently-
     seen variants are "500 Server error", "Method (something) not
     permitted", "Document contains no data", "Premature end of script
     headers", and "Did not produce a valid header".

     TThhiiss iiss aa CCGGII eerrrroorr,, nnoott aa PPeerrll eerrrroorr.

     You need to make sure your script is executable, is accessible by the
     user CGI is running the script under (which is probably not the user
     account you tested it under), does not rely on any environment
     variables (like PATH) from the user it isn't running under, and isn't
     in a location where the CGI server can't find it, basically, more or
     less.  Please see the following for more information:

             https://www.perl.org/CGI_MetaFAQ.html
             http://www.htmlhelp.org/faq/cgifaq.html
             http://www.w3.org/Security/Faq/

     You should also look at perlfaq9.

 sseetteeggiidd(()) not implemented
     (F) You tried to assign to $), and your operating system doesn't
     support the sseetteeggiidd(()) system call (or equivalent), or at least
     Configure didn't think so.

 sseetteeuuiidd(()) not implemented
     (F) You tried to assign to $>, and your operating system doesn't
     support the sseetteeuuiidd(()) system call (or equivalent), or at least
     Configure didn't think so.

 setpgrp can't take arguments
     (F) Your system has the sseettppggrrpp(()) from BSD 4.2, which takes no
     arguments, unlike POSIX sseettppggiidd(()), which takes a process ID and
     process group ID.

 sseettrrggiidd(()) not implemented
     (F) You tried to assign to $(, and your operating system doesn't
     support the sseettrrggiidd(()) system call (or equivalent), or at least
     Configure didn't think so.

 sseettrruuiidd(()) not implemented
     (F) You tried to assign to $<, and your operating system doesn't
     support the sseettrruuiidd(()) system call (or equivalent), or at least
     Configure didn't think so.

 sseettssoocckkoopptt(()) on closed socket %s
     (W closed) You tried to set a socket option on a closed socket.  Did
     you forget to check the return value of your ssoocckkeett(()) call?  See
     "setsockopt" in perlfunc.

 Setting $/ to a reference to %s is forbidden
     (F) You assigned a reference to a scalar to $/ where the referenced
     item is not a positive integer.  In older perls this aappppeeaarreedd to work
     the same as setting it to "undef" but was in fact internally
     different, less efficient and with very bad luck could have resulted
     in your file being split by a stringified form of the reference.

     In Perl 5.20.0 this was changed so that it would be eexxaaccttllyy the same
     as setting $/ to undef, with the exception that this warning would be
     thrown.

     You are recommended to change your code to set $/ to "undef"
     explicitly if you wish to slurp the file.  As of Perl 5.28 assigning
     $/ to a reference to an integer which isn't positive is a fatal
     error.

 Setting $/ to %s reference is forbidden
     (F) You tried to assign a reference to a non integer to $/.  In older
     Perls this would have behaved similarly to setting it to a reference
     to a positive integer, where the integer was the address of the
     reference.  As of Perl 5.20.0 this is a fatal error, to allow future
     versions of Perl to use non-integer refs for more interesting
     purposes.

 shm%s not implemented
     (F) You don't have System V shared memory IPC on your system.

 !=~ should be !~
     (W syntax) The non-matching operator is !~, not !=~.  !=~ will be
     interpreted as the != (numeric not equal) and ~ (1's complement)
     operators: probably not what you intended.

 /%s/ should probably be written as "%s"
     (W syntax) You have used a pattern where Perl expected to find a
     string, as in the first argument to "join".  Perl will treat the true
     or false result of matching the pattern against $_ as the string,
     which is probably not what you had in mind.

 sshhuuttddoowwnn(()) on closed socket %s
     (W closed) You tried to do a shutdown on a closed socket.  Seems a
     bit superfluous.

 SIG%s handler "%s" not defined
     (W signal) The signal handler named in %SIG doesn't, in fact, exist.
     Perhaps you put it into the wrong package?

 Slab leaked from cv %p
     (S) If you see this message, then something is seriously wrong with
     the internal bookkeeping of op trees.  An op tree needed to be freed
     after a compilation error, but could not be found, so it was leaked
     instead.

 sleep(%u) too large
     (W overflow) You called "sleep" with a number that was larger than it
     can reliably handle and "sleep" probably slept for less time than
     requested.

 Slurpy parameter not last
     (F) In a subroutine signature, you put something after a slurpy
     (array or hash) parameter.  The slurpy parameter takes all the
     available arguments, so there can't be any left to fill later
     parameters.

 Smart matching a non-overloaded object breaks encapsulation
     (F) You should not use the "~~" operator on an object that does not
     overload it: Perl refuses to use the object's underlying structure
     for the smart match.

 Smartmatch is experimental
     (S experimental::smartmatch) This warning is emitted if you use the
     smartmatch ("~~") operator.  This is currently an experimental
     feature, and its details are subject to change in future releases of
     Perl.  Particularly, its current behavior is noticed for being
     unnecessarily complex and unintuitive, and is very likely to be
     overhauled.

 Sorry, hash keys must be smaller than 2**31 bytes
     (F) You tried to create a hash containing a very large key, where
     "very large" means that it needs at least 2 gigabytes to store.
     Unfortunately, Perl doesn't yet handle such large hash keys. You
     should reconsider your design to avoid hashing such a long string
     directly.

 sort is now a reserved word
     (F) An ancient error message that almost nobody ever runs into
     anymore.  But before sort was a keyword, people sometimes used it as
     a filehandle.

 Source filters apply only to byte streams
     (F) You tried to activate a source filter (usually by loading a
     source filter module) within a string passed to "eval".  This is not
     permitted under the "unicode_eval" feature.  Consider using
     "evalbytes" instead.  See feature.

 sspplliiccee(()) offset past end of array
     (W misc) You attempted to specify an offset that was past the end of
     the array passed to sspplliiccee(()).  Splicing will instead commence at the
     end of the array, rather than past it.  If this isn't what you want,
     try explicitly pre-extending the array by assigning $#array =
     $offset.  See "splice" in perlfunc.

 Split loop
     (P) The split was looping infinitely.  (Obviously, a split shouldn't
     iterate more times than there are characters of input, which is what
     happened.)  See "split" in perlfunc.

 Statement unlikely to be reached
     (W exec) You did an eexxeecc(()) with some statement after it other than a
     ddiiee(()).  This is almost always an error, because eexxeecc(()) never returns
     unless there was a failure.  You probably wanted to use ssyysstteemm(())
     instead, which does return.  To suppress this warning, put the eexxeecc(())
     in a block by itself.

 "state" subroutine %s can't be in a package
     (F) Lexically scoped subroutines aren't in a package, so it doesn't
     make sense to try to declare one with a package qualifier on the
     front.

 "state %s" used in sort comparison
     (W syntax) The package variables $a and $b are used for sort
     comparisons.  You used $a or $b in as an operand to the "<=>" or
     "cmp" operator inside a sort comparison block, and the variable had
     earlier been declared as a lexical variable.  Either qualify the sort
     variable with the package name, or rename the lexical variable.

 "state" variable %s can't be in a package
     (F) Lexically scoped variables aren't in a package, so it doesn't
     make sense to try to declare one with a package qualifier on the
     front.  Use llooccaall(()) if you want to localize a package variable.

 ssttaatt(()) on unopened filehandle %s
     (W unopened) You tried to use the ssttaatt(()) function on a filehandle
     that was either never opened or has since been closed.

 Strings with code points over 0xFF may not be mapped into in-memory file
 handles
     (W utf8) You tried to open a reference to a scalar for read or append
     where the scalar contained code points over 0xFF.  In-memory files
     model on-disk files and can only contain bytes.

 Stub found while resolving method "%s" overloading "%s" in package "%s"
     (P) Overloading resolution over @ISA tree may be broken by
     importation stubs.  Stubs should never be implicitly created, but
     explicit calls to "can" may break this.

 Subroutine attributes must come before the signature
     (F) When subroutine signatures are enabled, any subroutine attributes
     must come before the signature. Note that this order was the opposite
     in versions 5.22..5.26. So:

         sub foo :lvalue ($a, $b) { ... }  # 5.20 and 5.28 +
         sub foo ($a, $b) :lvalue { ... }  # 5.22 .. 5.26

 Subroutine "&%s" is not available
     (W closure) During compilation, an inner named subroutine or eval is
     attempting to capture an outer lexical subroutine that is not
     currently available.  This can happen for one of two reasons.  First,
     the lexical subroutine may be declared in an outer anonymous
     subroutine that has not yet been created.  (Remember that named subs
     are created at compile time, while anonymous subs are created at run-
     time.)  For example,

         sub { my sub a {...} sub f { \&a } }

     At the time that f is created, it can't capture the current "a" sub,
     since the anonymous subroutine hasn't been created yet.  Conversely,
     the following won't give a warning since the anonymous subroutine has
     by now been created and is live:

         sub { my sub a {...} eval 'sub f { \&a }' }->();

     The second situation is caused by an eval accessing a lexical
     subroutine that has gone out of scope, for example,

         sub f {
             my sub a {...}
             sub { eval '\&a' }
         }
         f()->();

     Here, when the '\&a' in the eval is being compiled, f() is not
     currently being executed, so its &a is not available for capture.

 "%s" subroutine &%s masks earlier declaration in same %s
     (W shadow) A "my" or "state" subroutine has been redeclared in the
     current scope or statement, effectively eliminating all access to the
     previous instance.  This is almost always a typographical error.
     Note that the earlier subroutine will still exist until the end of
     the scope or until all closure references to it are destroyed.

 Subroutine %s redefined
     (W redefine) You redefined a subroutine.  To suppress this warning,
     say

         {
             no warnings 'redefine';
             eval "sub name { ... }";
         }

 Subroutine "%s" will not stay shared
     (W closure) An inner (nested) _n_a_m_e_d subroutine is referencing a "my"
     subroutine defined in an outer named subroutine.

     When the inner subroutine is called, it will see the value of the
     outer subroutine's lexical subroutine as it was before and during the
     *first* call to the outer subroutine; in this case, after the first
     call to the outer subroutine is complete, the inner and outer
     subroutines will no longer share a common value for the lexical
     subroutine.  In other words, it will no longer be shared.  This will
     especially make a difference if the lexical subroutines accesses
     lexical variables declared in its surrounding scope.

     This problem can usually be solved by making the inner subroutine
     anonymous, using the "sub {}" syntax.  When inner anonymous subs that
     reference lexical subroutines in outer subroutines are created, they
     are automatically rebound to the current values of such lexical subs.

 Substitution loop
     (P) The substitution was looping infinitely.  (Obviously, a
     substitution shouldn't iterate more times than there are characters
     of input, which is what happened.)  See the discussion of
     substitution in "Regexp Quote-Like Operators" in perlop.

 Substitution pattern not terminated
     (F) The lexer couldn't find the interior delimiter of an s/// or
     s{}{} construct.  Remember that bracketing delimiters count nesting
     level.  Missing the leading "$" from variable $s may cause this
     error.

 Substitution replacement not terminated
     (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
     construct.  Remember that bracketing delimiters count nesting level.
     Missing the leading "$" from variable $s may cause this error.

 substr outside of string
     (W substr)(F) You tried to reference a ssuubbssttrr(()) that pointed outside
     of a string.  That is, the absolute value of the offset was larger
     than the length of the string.  See "substr" in perlfunc.  This
     warning is fatal if substr is used in an lvalue context (as the left
     hand side of an assignment or as a subroutine argument for example).

 sv_upgrade from type %d down to type %d
     (P) Perl tried to force the upgrade of an SV to a type which was
     actually inferior to its current type.

 Switch (?(condition)... contains too many branches in regex; marked by
 <-- HERE in m/%s/
     (F) A (?(condition)if-clause|else-clause) construct can have at most
     two branches (the if-clause and the else-clause).  If you want one or
     both to contain alternation, such as using "this|that|other", enclose
     it in clustering parentheses:

         (?(condition)(?:this|that|other)|else-clause)

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Switch condition not recognized in regex; marked by <-- HERE in m/%s/
     (F) The condition part of a (?(condition)if-clause|else-clause)
     construct is not known.  The condition must be one of the following:

      (1) (2) ...        true if 1st, 2nd, etc., capture matched
      (<NAME>) ('NAME')  true if named capture matched
      (?=...) (?<=...)   true if subpattern matches
      (?!...) (?<!...)   true if subpattern fails to match
      (?{ CODE })        true if code returns a true value
      (R)                true if evaluating inside recursion
      (R1) (R2) ...      true if directly inside capture group 1, 2, etc.
      (R&NAME)           true if directly inside named capture
      (DEFINE)           always false; for defining named subpatterns

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Switch (?(condition)... not terminated in regex; marked by <-- HERE in
 m/%s/
     (F) You omitted to close a (?(condition)...) block somewhere in the
     pattern.  Add a closing parenthesis in the appropriate position.  See
     perlre.

 switching effective %s is not implemented
     (F) While under the "use filetest" pragma, we cannot switch the real
     and effective uids or gids.

 syntax error
     (F) Probably means you had a syntax error.  Common reasons include:

         A keyword is misspelled.
         A semicolon is missing.
         A comma is missing.
         An opening or closing parenthesis is missing.
         An opening or closing brace is missing.
         A closing quote is missing.

     Often there will be another error message associated with the syntax
     error giving more information.  (Sometimes it helps to turn on --ww.)
     The error message itself often tells you where it was in the line
     when it decided to give up.  Sometimes the actual error is several
     tokens before this, because Perl is good at understanding random
     input.  Occasionally the line number may be misleading, and once in a
     blue moon the only way to figure out what's triggering the error is
     to call "perl -c" repeatedly, chopping away half the program each
     time to see if the error went away.  Sort of the cybernetic version
     of 20 questions.

 syntax error at line %d: '%s' unexpected
     (A) You've accidentally run your script through the Bourne shell
     instead of Perl.  Check the #! line, or manually feed your script
     into Perl yourself.

 syntax error in file %s at line %d, next 2 tokens "%s"
     (F) This error is likely to occur if you run a perl5 script through a
     perl4 interpreter, especially if the next 2 tokens are "use strict"
     or "my $var" or "our $var".

 Syntax error in (?[...]) in regex; marked by <-- HERE in m/%s/
     (F) Perl could not figure out what you meant inside this construct;
     this notifies you that it is giving up trying.

 %s syntax OK
     (F) The final summary message when a "perl -c" succeeds.

 ssyyssrreeaadd(()) on closed filehandle %s
     (W closed) You tried to read from a closed filehandle.

 ssyyssrreeaadd(()) on unopened filehandle %s
     (W unopened) You tried to read from a filehandle that was never
     opened.

 System V %s is not implemented on this machine
     (F) You tried to do something with a function beginning with "sem",
     "shm", or "msg" but that System V IPC is not implemented in your
     machine.  In some machines the functionality can exist but be
     unconfigured.  Consult your system support.

 ssyysswwrriittee(()) on closed filehandle %s
     (W closed) The filehandle you're writing to got itself closed
     sometime before now.  Check your control flow.

 "-T" and "-B" not implemented on filehandles
     (F) Perl can't peek at the stdio buffer of filehandles when it
     doesn't know about your kind of stdio.  You'll have to use a filename
     instead.

 Target of goto is too deeply nested
     (F) You tried to use "goto" to reach a label that was too deeply
     nested for Perl to reach.  Perl is doing you a favor by refusing.

 tteellllddiirr(()) attempted on invalid dirhandle %s
     (W io) The dirhandle you tried to tteellllddiirr(()) is either closed or not
     really a dirhandle.  Check your control flow.

 tteellll(()) on unopened filehandle
     (W unopened) You tried to use the tteellll(()) function on a filehandle
     that was either never opened or has since been closed.

 The ccrryypptt(()) function is unimplemented due to excessive paranoia.
     (F) Configure couldn't find the ccrryypptt(()) function on your machine,
     probably because your vendor didn't supply it, probably because they
     think the U.S. Government thinks it's a secret, or at least that they
     will continue to pretend that it is.  And if you quote me on that, I
     will deny it.

 The experimental declared_refs feature is not enabled
     (F) To declare references to variables, as in "my \%x", you must
     first enable the feature:

         no warnings "experimental::declared_refs";
         use feature "declared_refs";

 The %s function is unimplemented
     (F) The function indicated isn't implemented on this architecture,
     according to the probings of Configure.

 The private_use feature is experimental
     (S experimental::private_use) This feature is actually a hook for
     future use.

 The stat preceding %s wasn't an lstat
     (F) It makes no sense to test the current stat buffer for symbolic
     linkhood if the last stat that wrote to the stat buffer already went
     past the symlink to get to the real file.  Use an actual filename
     instead.

 The Unicode property wildcards feature is experimental
     (S experimental::uniprop_wildcards) This feature is experimental and
     its behavior may in any future release of perl.  See "Wildcards in
     Property Values" in perlunicode.

 The 'unique' attribute may only be applied to 'our' variables
     (F) This attribute was never supported on "my" or "sub" declarations.

 This Perl can't reset CRTL environ elements (%s)
 This Perl can't set CRTL environ elements (%s=%s)
     (W internal) Warnings peculiar to VMS.  You tried to change or delete
     an element of the CRTL's internal environ array, but your copy of
     Perl wasn't built with a CRTL that contained the sseetteennvv(()) function.
     You'll need to rebuild Perl with a CRTL that does, or redefine
     _P_E_R_L___E_N_V___T_A_B_L_E_S (see perlvms) so that the environ array isn't the
     target of the change to %ENV which produced the warning.

 This Perl has not been built with support for randomized hash key
 traversal but something called PPeerrll__hhvv__rraanndd__sseett(()).
     (F) Something has attempted to use an internal API call which depends
     on Perl being compiled with the default support for randomized hash
     key traversal, but this Perl has been compiled without it.  You
     should report this warning to the relevant upstream party, or
     recompile perl with default options.

 This use of mmyy(()) in false conditional is no longer allowed
     (F) You used a declaration similar to "my $x if 0".  There has been a
     long-standing bug in Perl that causes a lexical variable not to be
     cleared at scope exit when its declaration includes a false
     conditional.  Some people have exploited this bug to achieve a kind
     of static variable.  Since we intend to fix this bug, we don't want
     people relying on this behavior.  You can achieve a similar static
     effect by declaring the variable in a separate block outside the
     function, eg

         sub f { my $x if 0; return $x++ }

     becomes

         { my $x; sub f { return $x++ } }

     Beginning with perl 5.10.0, you can also use "state" variables to
     have lexicals that are initialized only once (see feature):

         sub f { state $x; return $x++ }

     This use of "my()" in a false conditional was deprecated beginning in
     Perl 5.10 and became a fatal error in Perl 5.30.

 Timeout waiting for another thread to define \p{%s}
     (F) The first time a user-defined property ("User-Defined Character
     Properties" in perlunicode) is used, its definition is looked up and
     converted into an internal form for more efficient handling in
     subsequent uses.  There could be a race if two or more threads tried
     to do this processing nearly simultaneously.  Instead, a critical
     section is created around this task, locking out all but one thread
     from doing it.  This message indicates that the thread that is doing
     the conversion is taking an unexpectedly long time.  The timeout
     exists solely to prevent deadlock; it's long enough that the system
     was likely thrashing and about to crash.  There is no real remedy but
     rebooting.

 times not implemented
     (F) Your version of the C library apparently doesn't do ttiimmeess(()).  I
     suspect you're not running on Unix.

 "-T" is on the #! line, it must also be used on the command line
     (X) The #! line (or local equivalent) in a Perl script contains the
     --TT option (or the --tt option), but Perl was not invoked with --TT in its
     command line.  This is an error because, by the time Perl discovers a
     --TT in a script, it's too late to properly taint everything from the
     environment.  So Perl gives up.

     If the Perl script is being executed as a command using the #!
     mechanism (or its local equivalent), this error can usually be fixed
     by editing the #! line so that the --%%cc option is a part of Perl's
     first argument: e.g. change "perl -n -%c" to "perl -%c -n".

     If the Perl script is being executed as "perl scriptname", then the
     --%%cc option must appear on the command line: "perl -%c scriptname".

 To%s: illegal mapping '%s'
     (F) You tried to define a customized To-mapping for llcc(()), lcfirst,
     uucc(()), or uuccffiirrsstt(()) (or their string-inlined versions), but you
     specified an illegal mapping.  See "User-Defined Character
     Properties" in perlunicode.

 Too deeply nested ()-groups
     (F) Your template contains ()-groups with a ridiculously deep nesting
     level.

 Too few args to syscall
     (F) There has to be at least one argument to ssyyssccaallll(()) to specify the
     system call to call, silly dilly.

 Too few arguments for subroutine '%s' (got %d; expected %d)
     (F) A subroutine using a signature fewer arguments than required by
     the signature.  The caller of the subroutine is presumably at fault.

     The message attempts to include the name of the called subroutine.
     If the subroutine has been aliased, the subroutine's original name
     will be shown, regardless of what name the caller used. It will also
     indicate the number of arguments given and the number expected.

 Too few arguments for subroutine '%s' (got %d; expected at least %d)
     Similar to the previous message but for subroutines that accept a
     variable number of arguments.

 Too late for "-%s" option
     (X) The #! line (or local equivalent) in a Perl script contains the
     --MM, --mm or --CC option.

     In the case of --MM and --mm, this is an error because those options are
     not intended for use inside scripts.  Use the "use" pragma instead.

     The --CC option only works if it is specified on the command line as
     well (with the same sequence of letters or numbers following).
     Either specify this option on the command line, or, if your system
     supports it, make your script executable and run it directly instead
     of passing it to perl.

 Too late to run %s block
     (W void) A CHECK or INIT block is being defined during run time
     proper, when the opportunity to run them has already passed.  Perhaps
     you are loading a file with "require" or "do" when you should be
     using "use" instead.  Or perhaps you should put the "require" or "do"
     inside a BEGIN block.

 Too many args to syscall
     (F) Perl supports a maximum of only 14 args to ssyyssccaallll(()).

 Too many arguments for %s
     (F) The function requires fewer arguments than you specified.

 Too many arguments for subroutine '%s' (got %d; expected %d)
     (F) A subroutine using a signature received more arguments than
     permitted by the signature.  The caller of the subroutine is
     presumably at fault.

     The message attempts to include the name of the called subroutine. If
     the subroutine has been aliased, the subroutine's original name will
     be shown, regardless of what name the caller used. It will also
     indicate the number of arguments given and the number expected.

 Too many arguments for subroutine '%s' (got %d; expected at most %d)
     Similar to the previous message but for subroutines that accept a
     variable number of arguments.

 Too many nested open parens in regex; marked by <-- HERE in m/%s/
     (F) You have exceeded the number of open "(" parentheses that haven't
     been matched by corresponding closing ones.  This limit prevents
     eating up too much memory.  It is initially set to 1000, but may be
     changed by setting "${^RE_COMPILE_RECURSION_LIMIT}" to some other
     value.  This may need to be done in a BEGIN block before the regular
     expression pattern is compiled.

 Too many )'s
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 Too many ('s
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 Trailing \ in regex m/%s/
     (F) The regular expression ends with an unbackslashed backslash.
     Backslash it.   See perlre.

 Transliteration pattern not terminated
     (F) The lexer couldn't find the interior delimiter of a tr/// or
     tr[][] or y/// or y[][] construct.  Missing the leading "$" from
     variables $tr or $y may cause this error.

 Transliteration replacement not terminated
     (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
     y/// or y[][] construct.

 '%s' trapped by operation mask
     (F) You tried to use an operator from a Safe compartment in which
     it's disallowed.  See Safe.

 truncate not implemented
     (F) Your machine doesn't implement a file truncation mechanism that
     Configure knows about.

 try/catch is experimental
     (S experimental::try) This warning is emitted if you use the "try"
     and "catch" syntax. This syntax is currently experimental and its
     behaviour may change in future releases of Perl.

 try/catch/finally is experimental
     (S experimental::try) This warning is emitted if you use the "try"
     and "catch" syntax with a "finally" block. This syntax is currently
     experimental and its behaviour may change in future releases of Perl.

 Type of arg %d to &CORE::%s must be %s
     (F) The subroutine in question in the CORE package requires its
     argument to be a hard reference to data of the specified type.
     Overloading is ignored, so a reference to an object that is not the
     specified type, but nonetheless has overloading to handle it, will
     still not be accepted.

 Type of arg %d to %s must be %s (not %s)
     (F) This function requires the argument in that position to be of a
     certain type.  Arrays must be @NAME or "@{EXPR}".  Hashes must be
     %NAME or "%{EXPR}".  No implicit dereferencing is allowed--use the
     {EXPR} forms as an explicit dereference.  See perlref.

 umask not implemented
     (F) Your machine doesn't implement the umask function and you tried
     to use it to restrict permissions for yourself (EXPR & 0700).

 Unbalanced context: %d more PUSHes than POPs
     (S internal) The exit code detected an internal inconsistency in how
     many execution contexts were entered and left.

 Unbalanced saves: %d more saves than restores
     (S internal) The exit code detected an internal inconsistency in how
     many values were temporarily localized.

 Unbalanced scopes: %d more ENTERs than LEAVEs
     (S internal) The exit code detected an internal inconsistency in how
     many blocks were entered and left.

 Unbalanced string table refcount: (%d) for "%s"
     (S internal) On exit, Perl found some strings remaining in the shared
     string table used for copy on write and for hash keys.  The entries
     should have been freed, so this indicates a bug somewhere.

 Unbalanced tmps: %d more allocs than frees
     (S internal) The exit code detected an internal inconsistency in how
     many mortal scalars were allocated and freed.

 Undefined format "%s" called
     (F) The format indicated doesn't seem to exist.  Perhaps it's really
     in another package?  See perlform.

 Undefined sort subroutine "%s" called
     (F) The sort comparison routine specified doesn't seem to exist.
     Perhaps it's in a different package?  See "sort" in perlfunc.

 Undefined subroutine &%s called
     (F) The subroutine indicated hasn't been defined, or if it was, it
     has since been undefined.

 Undefined subroutine called
     (F) The anonymous subroutine you're trying to call hasn't been
     defined, or if it was, it has since been undefined.

 Undefined subroutine in sort
     (F) The sort comparison routine specified is declared but doesn't
     seem to have been defined yet.  See "sort" in perlfunc.

 Undefined top format "%s" called
     (F) The format indicated doesn't seem to exist.  Perhaps it's really
     in another package?  See perlform.

 Undefined value assigned to typeglob
     (W misc) An undefined value was assigned to a typeglob, a la "*foo =
     undef".  This does nothing.  It's possible that you really mean
     "undef *foo".

 %s: Undefined variable
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 Unescaped left brace in regex is illegal here in regex; marked by
 <-- HERE in m/%s/
     (F) The simple rule to remember, if you want to match a literal "{"
     character (U+007B "LEFT CURLY BRACKET") in a regular expression
     pattern, is to escape each literal instance of it in some way.
     Generally easiest is to precede it with a backslash, like "\{" or
     enclose it in square brackets ("[{]").  If the pattern delimiters are
     also braces, any matching right brace ("}") should also be escaped to
     avoid confusing the parser, for example,

      qr{abc\{def\}ghi}

     Forcing literal "{" characters to be escaped enables the Perl
     language to be extended in various ways in future releases.  To avoid
     needlessly breaking existing code, the restriction is not enforced in
     contexts where there are unlikely to ever be extensions that could
     conflict with the use there of "{" as a literal.  Those that are not
     potentially ambiguous do not warn; those that are do raise a non-
     deprecation warning.

     The contexts where no warnings or errors are raised are:

     •   as the first character in a pattern, or following "^" indicating
         to anchor the match to the beginning of a line.

     •   as the first character following a "|" indicating alternation.

     •   as the first character in a parenthesized grouping like

          /foo({bar)/
          /foo(?:{bar)/

     •   as the first character following a quantifier

          /\s*{/

 Unescaped left brace in regex is passed through in regex; marked by
 <-- HERE in m/%s/
     (W regexp)  The simple rule to remember, if you want to match a
     literal "{" character (U+007B "LEFT CURLY BRACKET") in a regular
     expression pattern, is to escape each literal instance of it in some
     way.  Generally easiest is to precede it with a backslash, like "\{"
     or enclose it in square brackets ("[{]").  If the pattern delimiters
     are also braces, any matching right brace ("}") should also be
     escaped to avoid confusing the parser, for example,

      qr{abc\{def\}ghi}

     Forcing literal "{" characters to be escaped enables the Perl
     language to be extended in various ways in future releases.  To avoid
     needlessly breaking existing code, the restriction is not enforced in
     contexts where there are unlikely to ever be extensions that could
     conflict with the use there of "{" as a literal.  Those that are not
     potentially ambiguous do not warn; those that are raise this warning.
     This makes sure that an inadvertent typo doesn't silently cause the
     pattern to compile to something unintended.

     The contexts where no warnings or errors are raised are:

     •   as the first character in a pattern, or following "^" indicating
         to anchor the match to the beginning of a line.

     •   as the first character following a "|" indicating alternation.

     •   as the first character in a parenthesized grouping like

          /foo({bar)/
          /foo(?:{bar)/

     •   as the first character following a quantifier

          /\s*{/

 Unescaped literal '%c' in regex; marked by <-- HERE in m/%s/
     (W regexp) (only under "use re 'strict'")

     Within the scope of "use re 'strict'" in a regular expression
     pattern, you included an unescaped "}" or "]" which was interpreted
     literally.  These two characters are sometimes metacharacters, and
     sometimes literals, depending on what precedes them in the pattern.
     This is unlike the similar ")" which is always a metacharacter unless
     escaped.

     This action at a distance, perhaps a large distance, can lead to Perl
     silently misinterpreting what you meant, so when you specify that you
     want extra checking by "use re 'strict'", this warning is generated.
     If you meant the character as a literal, simply confirm that to Perl
     by preceding the character with a backslash, or make it into a
     bracketed character class (like "[}]").  If you meant it as closing a
     corresponding "[" or "{", you'll need to look back through the
     pattern to find out why that isn't happening.

 unexec of %s into %s failed!
     (F) The uunneexxeecc(()) routine failed for some reason.  See your local FSF
     representative, who probably put it there in the first place.

 Unexpected binary operator '%c' with no preceding operand in regex;
 marked by <-- HERE in m/%s/
     (F) You had something like this:

      (?[ | \p{Digit} ])

     where the "|" is a binary operator with an operand on the right, but
     no operand on the left.

 Unexpected character in regex; marked by <-- HERE in m/%s/
     (F) You had something like this:

      (?[ z ])

     Within "(?[ ])", no literal characters are allowed unless they are
     within an inner pair of square brackets, like

      (?[ [ z ] ])

     Another possibility is that you forgot a backslash.  Perl isn't smart
     enough to figure out what you really meant.

 Unexpected exit %u
     (S) eexxiitt(()) was called or the script otherwise finished gracefully
     when "PERL_EXIT_WARN" was set in "PL_exit_flags".

 Unexpected exit failure %d
     (S) An uncaught ddiiee(()) was called when "PERL_EXIT_WARN" was set in
     "PL_exit_flags".

 Unexpected ')' in regex; marked by <-- HERE in m/%s/
     (F) You had something like this:

      (?[ ( \p{Digit} + ) ])

     The ")" is out-of-place.  Something apparently was supposed to be
     combined with the digits, or the "+" shouldn't be there, or something
     like that.  Perl can't figure out what was intended.

 Unexpected ']' with no following ')' in (?[... in regex; marked by <--
 HERE in m/%s/
     (F) While parsing an extended character class a ']' character was
     encountered at a point in the definition where the only legal use of
     ']' is to close the character class definition as part of a '])', you
     may have forgotten the close paren, or otherwise confused the parser.

 Unexpected '(' with no preceding operator in regex; marked by <-- HERE in
 m/%s/
     (F) You had something like this:

      (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])

     There should be an operator before the "(", as there's no indication
     as to how the digits are to be combined with the characters in the
     Lao and Thai scripts.

 Unicode non-character U+%X is not recommended for open interchange
     (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
     defined by the Unicode standard to be non-characters.  Those are
     legal codepoints, but are reserved for internal use; so, applications
     shouldn't attempt to exchange them.  An application may not be
     expecting any of these characters at all, and receiving them may lead
     to bugs.  If you know what you are doing you can turn off this
     warning by "no warnings 'nonchar';".

     This is not really a "severe" error, but it is supposed to be raised
     by default even if warnings are not enabled, and currently the only
     way to do that in Perl is to mark it as serious.

 Unicode property wildcard not terminated
     (F) A Unicode property wildcard looks like a delimited regular
     expression pattern (all within the braces of the enclosing "\p{...}".
     The closing delimtter to match the opening one was not found.  If the
     opening one is escaped by preceding it with a backslash, the closing
     one must also be so escaped.

 Unicode string properties are not implemented in (?[...]) in regex;
 marked by <-- HERE in m/%s/
     (F) A Unicode string property is one which expands to a sequence of
     multiple characters.  An example is "\p{name=KATAKANA LETTER AINU
     P}", which is comprised of the sequence "\N{KATAKANA LETTER SMALL H}"
     followed by "\N{COMBINING KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK}".
     Extended character classes, "(?[...])" currently cannot handle these.

 Unicode surrogate U+%X is illegal in UTF-8
     (S surrogate) You had a UTF-16 surrogate in a context where they are
     not considered acceptable.  These code points, between U+D800 and
     U+DFFF (inclusive), are used by Unicode only for UTF-16.  However,
     Perl internally allows all unsigned integer code points (up to the
     size limit available on your platform), including surrogates.  But
     these can cause problems when being input or output, which is likely
     where this message came from.  If you really really know what you are
     doing you can turn off this warning by "no warnings 'surrogate';".

 Unknown charname '%s'
     (F) The name you used inside "\N{}" is unknown to Perl.  Check the
     spelling.  You can say "use charnames ":loose"" to not have to be so
     precise about spaces, hyphens, and capitalization on standard Unicode
     names.  (Any custom aliases that have been created must be specified
     exactly, regardless of whether ":loose" is used or not.)  This error
     may also happen if the "\N{}" is not in the scope of the
     corresponding "use charnames".

 Unknown '(*...)' construct '%s' in regex; marked by <-- HERE in m/%s/
     (F) The "(*" was followed by something that the regular expression
     compiler does not recognize.  Check your spelling.

 Unknown error
     (P) Perl was about to print an error message in $@, but the $@
     variable did not exist, even after an attempt to create it.

 Unknown locale category %d; can't set it to %s
     (W locale) You used a locale category that perl doesn't recognize, so
     it cannot carry out your request.  Check that you are using a valid
     category.  If so, see "Multi-threaded" in perllocale for advice on
     reporting this as a bug, and for modifying perl locally to
     accommodate your needs.

 Unknown ooppeenn(()) mode '%s'
     (F) The second argument of 3-argument ooppeenn(()) is not among the list of
     valid modes: "<", ">", ">>", "+<", "+>", "+>>", "-|", "|-", "<&",
     ">&".

 Unknown PerlIO layer "%s"
     (W layer) An attempt was made to push an unknown layer onto the Perl
     I/O system.  (Layers take care of transforming data between external
     and internal representations.)  Note that some layers, such as
     "mmap", are not supported in all environments.  If your program
     didn't explicitly request the failing operation, it may be the result
     of the value of the environment variable PERLIO.

 Unknown process %x sent message to prime_env_iter: %s
     (P) An error peculiar to VMS.  Perl was reading values for %ENV
     before iterating over it, and someone else stuck a message in the
     stream of data Perl expected.  Someone's very confused, or perhaps
     trying to subvert Perl's population of %ENV for nefarious purposes.

 Unknown regexp modifier "/%s"
     (F) Alphanumerics immediately following the closing delimiter of a
     regular expression pattern are interpreted by Perl as modifier flags
     for the regex.  One of the ones you specified is invalid.  One way
     this can happen is if you didn't put in white space between the end
     of the regex and a following alphanumeric operator:

      if ($a =~ /foo/and $bar == 3) { ... }

     The "a" is a valid modifier flag, but the "n" is not, and raises this
     error.  Likely what was meant instead was:

      if ($a =~ /foo/ and $bar == 3) { ... }

 Unknown "re" subpragma '%s' (known ones are: %s)
     (W) You tried to use an unknown subpragma of the "re" pragma.

 Unknown switch condition (?(...)) in regex; marked by <-- HERE in m/%s/
     (F) The condition part of a (?(condition)if-clause|else-clause)
     construct is not known.  The condition must be one of the following:

      (1) (2) ...            true if 1st, 2nd, etc., capture matched
      (<NAME>) ('NAME')      true if named capture matched
      (?=...) (?<=...)       true if subpattern matches
      (*pla:...) (*plb:...)  true if subpattern matches; also
                                  (*positive_lookahead:...)
                                  (*positive_lookbehind:...)
      (*nla:...) (*nlb:...)  true if subpattern fails to match; also
                                  (*negative_lookahead:...)
                                  (*negative_lookbehind:...)
      (?{ CODE })            true if code returns a true value
      (R)                    true if evaluating inside recursion
      (R1) (R2) ...          true if directly inside capture group 1, 2,
                                  etc.
      (R&NAME)               true if directly inside named capture
      (DEFINE)               always false; for defining named subpatterns

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Unknown Unicode option letter '%c'
     (F) You specified an unknown Unicode option.  See perlrun
     documentation of the "-C" switch for the list of known options.

 Unknown Unicode option value %d
     (F) You specified an unknown Unicode option.  See perlrun
     documentation of the "-C" switch for the list of known options.

 Unknown user-defined property name \p{%s}
     (F) You specified to use a property within the "\p{...}" which was a
     syntactically valid user-defined property, but no definition was
     found for it by the time one was required to proceed.  Check your
     spelling.  See "User-Defined Character Properties" in perlunicode.

 Unknown verb pattern '%s' in regex; marked by <-- HERE in m/%s/
     (F) You either made a typo or have incorrectly put a "*" quantifier
     after an open brace in your pattern.  Check the pattern and review
     perlre for details on legal verb patterns.

 Unknown warnings category '%s'
     (F) An error issued by the "warnings" pragma.  You specified a
     warnings category that is unknown to perl at this point.

     Note that if you want to enable a warnings category registered by a
     module (e.g. "use warnings 'File::Find'"), you must have loaded this
     module first.

 Unmatched [ in regex; marked by <-- HERE in m/%s/
     (F) The brackets around a character class must match.  If you wish to
     include a closing bracket in a character class, backslash it or put
     it first.  The <-- HERE shows whereabouts in the regular expression
     the problem was discovered.  See perlre.

 Unmatched ( in regex; marked by <-- HERE in m/%s/
 Unmatched ) in regex; marked by <-- HERE in m/%s/
     (F) Unbackslashed parentheses must always be balanced in regular
     expressions.  If you're a vi user, the % key is valuable for finding
     the matching parenthesis.  The <-- HERE shows whereabouts in the
     regular expression the problem was discovered.  See perlre.

 Unmatched right %s bracket
     (F) The lexer counted more closing curly or square brackets than
     opening ones, so you're probably missing a matching opening bracket.
     As a general rule, you'll find the missing one (so to speak) near the
     place you were last editing.

 Unquoted string "%s" may clash with future reserved word
     (W reserved) You used a bareword that might someday be claimed as a
     reserved word.  It's best to put such a word in quotes, or capitalize
     it somehow, or insert an underbar into it.  You might also declare it
     as a subroutine.

 Unrecognized character %s; marked by <-- HERE after %s near column %d
     (F) The Perl parser has no idea what to do with the specified
     character in your Perl script (or eval) near the specified column.
     Perhaps you tried  to run a compressed script, a binary program, or a
     directory as a Perl program.

 Unrecognized escape \%c in character class in regex; marked by <-- HERE
 in m/%s/
     (F) You used a backslash-character combination which is not
     recognized by Perl inside character classes.  This is a fatal error
     when the character class is used within "(?[ ])".

 Unrecognized escape \%c in character class passed through in regex;
 marked by <-- HERE in m/%s/
     (W regexp) You used a backslash-character combination which is not
     recognized by Perl inside character classes.  The character was
     understood literally, but this may change in a future version of
     Perl.  The <-- HERE shows whereabouts in the regular expression the
     escape was discovered.

 Unrecognized escape \%c passed through
     (W misc) You used a backslash-character combination which is not
     recognized by Perl.  The character was understood literally, but this
     may change in a future version of Perl.

 Unrecognized escape \%s passed through in regex; marked by <-- HERE in
 m/%s/
     (W regexp) You used a backslash-character combination which is not
     recognized by Perl.  The character(s) were understood literally, but
     this may change in a future version of Perl.  The <-- HERE shows
     whereabouts in the regular expression the escape was discovered.

 Unrecognized signal name "%s"
     (F) You specified a signal name to the kkiillll(()) function that was not
     recognized.  Say "kill -l" in your shell to see the valid signal
     names on your system.

 Unrecognized switch: -%s  (-h will show valid options)
     (F) You specified an illegal option to Perl.  Don't do that.  (If you
     think you didn't do that, check the #! line to see if it's supplying
     the bad switch on your behalf.)

 Unsuccessful %s on filename containing newline
     (W newline) A file operation was attempted on a filename, and that
     operation failed, PROBABLY because the filename contained a newline,
     PROBABLY because you forgot to cchhoommpp(()) it off.  See "chomp" in
     perlfunc.

 Unsupported directory function "%s" called
     (F) Your machine doesn't support ooppeennddiirr(()) and rreeaaddddiirr(()).

 Unsupported function %s
     (F) This machine doesn't implement the indicated function,
     apparently.  At least, Configure doesn't think so.

 Unsupported function fork
     (F) Your version of executable does not support forking.

     Note that under some systems, like OS/2, there may be different
     flavors of Perl executables, some of which may support fork, some
     not.  Try changing the name you call Perl by to "perl_", "perl__",
     and so on.

 Unsupported script encoding %s
     (F) Your program file begins with a Unicode Byte Order Mark (BOM)
     which declares it to be in a Unicode encoding that Perl cannot read.

 Unsupported socket function "%s" called
     (F) Your machine doesn't support the Berkeley socket mechanism, or at
     least that's what Configure thought.

 Unterminated '(*...' argument in regex; marked by <-- HERE in m/%s/
     (F) You used a pattern of the form "(*...:...)" but did not terminate
     the pattern with a ")".  Fix the pattern and retry.

 Unterminated attribute list
     (F) The lexer found something other than a simple identifier at the
     start of an attribute, and it wasn't a semicolon or the start of a
     block.  Perhaps you terminated the parameter list of the previous
     attribute too soon.  See attributes.

 Unterminated attribute parameter in attribute list
     (F) The lexer saw an opening (left) parenthesis character while
     parsing an attribute list, but the matching closing (right)
     parenthesis character was not found.  You may need to add (or remove)
     a backslash character to get your parentheses to balance.  See
     attributes.

 Unterminated compressed integer
     (F) An argument to unpack("w",...) was incompatible with the BER
     compressed integer format and could not be converted to an integer.
     See "pack" in perlfunc.

 Unterminated '(*...' construct in regex; marked by <-- HERE in m/%s/
     (F) You used a pattern of the form "(*...)" but did not terminate the
     pattern with a ")".  Fix the pattern and retry.

 Unterminated delimiter for here document
     (F) This message occurs when a here document label has an initial
     quotation mark but the final quotation mark is missing.  Perhaps you
     wrote:

         <<"foo

     instead of:

         <<"foo"

 Unterminated \g... pattern in regex; marked by <-- HERE in m/%s/
 Unterminated \g{...} pattern in regex; marked by <-- HERE in m/%s/
     (F) In a regular expression, you had a "\g" that wasn't followed by a
     proper group reference.  In the case of "\g{", the closing brace is
     missing; otherwise the "\g" must be followed by an integer.  Fix the
     pattern and retry.

 Unterminated <> operator
     (F) The lexer saw a left angle bracket in a place where it was
     expecting a term, so it's looking for the corresponding right angle
     bracket, and not finding it.  Chances are you left some needed
     parentheses out earlier in the line, and you really meant a "less
     than".

 Unterminated verb pattern argument in regex; marked by <-- HERE in m/%s/
     (F) You used a pattern of the form "(*VERB:ARG)" but did not
     terminate the pattern with a ")".  Fix the pattern and retry.

 Unterminated verb pattern in regex; marked by <-- HERE in m/%s/
     (F) You used a pattern of the form "(*VERB)" but did not terminate
     the pattern with a ")".  Fix the pattern and retry.

 untie attempted while %d inner references still exist
     (W untie) A copy of the object returned from "tie" (or "tied") was
     still valid when "untie" was called.

 Usage: POSIX::%s(%s)
     (F) You called a POSIX function with incorrect arguments.  See
     "FUNCTIONS" in POSIX for more information.

 Usage: Win32::%s(%s)
     (F) You called a Win32 function with incorrect arguments.  See Win32
     for more information.

 $[ used in %s (did you mean $] ?)
     (W syntax) You used $[ in a comparison, such as:

         if ($[ > 5.006) {
             ...
         }

     You probably meant to use $] instead.  $[ is the base for indexing
     arrays.  $] is the Perl version number in decimal.

 Use "%s" instead of "%s"
     (F) The second listed construct is no longer legal.  Use the first
     one instead.

 Useless assignment to a temporary
     (W misc) You assigned to an lvalue subroutine, but what the
     subroutine returned was a temporary scalar about to be discarded, so
     the assignment had no effect.

 Useless (?-%s) - don't use /%s modifier in regex; marked by <-- HERE in
 m/%s/
     (W regexp) You have used an internal modifier such as (?-o) that has
     no meaning unless removed from the entire regexp:

         if ($string =~ /(?-o)$pattern/o) { ... }

     must be written as

         if ($string =~ /$pattern/) { ... }

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Useless localization of %s
     (W syntax) The localization of lvalues such as "local($x=10)" is
     legal, but in fact the llooccaall(()) currently has no effect.  This may
     change at some point in the future, but in the meantime such code is
     discouraged.

 Useless (?%s) - use /%s modifier in regex; marked by <-- HERE in m/%s/
     (W regexp) You have used an internal modifier such as (?o) that has
     no meaning unless applied to the entire regexp:

         if ($string =~ /(?o)$pattern/) { ... }

     must be written as

         if ($string =~ /$pattern/o) { ... }

     The <-- HERE shows whereabouts in the regular expression the problem
     was discovered.  See perlre.

 Useless use of attribute "const"
     (W misc) The "const" attribute has no effect except on anonymous
     closure prototypes.  You applied it to a subroutine via
     attributes.pm.  This is only useful inside an attribute handler for
     an anonymous subroutine.

 Useless use of /d modifier in transliteration operator
     (W misc) You have used the /d modifier where the searchlist has the
     same length as the replacelist.  See perlop for more information
     about the /d modifier.

 Useless use of \E
     (W misc) You have a \E in a double-quotish string without a "\U",
     "\L" or "\Q" preceding it.

 Useless use of greediness modifier '%c' in regex; marked by <-- HERE in
 m/%s/
     (W regexp) You specified something like these:

      qr/a{3}?/
      qr/b{1,1}+/

     The "?" and "+" don't have any effect, as they modify whether to
     match more or fewer when there is a choice, and by specifying to
     match exactly a given number, there is no room left for a choice.

 Useless use of %s in scalar context
     (W scalar) You did something whose only interesting return value is a
     list without a side effect in scalar context, which does not accept a
     list.

     For example

         my $x = sort @y;

     This is not very useful, and perl currently optimizes this away.

 Useless use of %s in void context
     (W void) You did something without a side effect in a context that
     does nothing with the return value, such as a statement that doesn't
     return a value from a block, or the left side of a scalar comma
     operator.  Very often this points not to stupidity on your part, but
     a failure of Perl to parse your program the way you thought it would.
     For example, you'd get this if you mixed up your C precedence with
     Python precedence and said

         $one, $two = 1, 2;

     when you meant to say

         ($one, $two) = (1, 2);

     Another common error is to use ordinary parentheses to construct a
     list reference when you should be using square or curly brackets, for
     example, if you say

         $array = (1,2);

     when you should have said

         $array = [1,2];

     The square brackets explicitly turn a list value into a scalar value,
     while parentheses do not.  So when a parenthesized list is evaluated
     in a scalar context, the comma is treated like C's comma operator,
     which throws away the left argument, which is not what you want.  See
     perlref for more on this.

     This warning will not be issued for numerical constants equal to 0 or
     1 since they are often used in statements like

         1 while sub_with_side_effects();

     String constants that would normally evaluate to 0 or 1 are warned
     about.

 Useless use of (?-p) in regex; marked by <-- HERE in m/%s/
     (W regexp) The "p" modifier cannot be turned off once set.  Trying to
     do so is futile.

 Useless use of "re" pragma
     (W) You did "use re;" without any arguments.  That isn't very useful.

 Useless use of %s with no values
     (W syntax) You used the ppuusshh(()) or uunnsshhiifftt(()) function with no
     arguments apart from the array, like "push(@x)" or "unshift(@foo)".
     That won't usually have any effect on the array, so is completely
     useless.  It's possible in principle that push(@tied_array) could
     have some effect if the array is tied to a class which implements a
     PUSH method.  If so, you can write it as "push(@tied_array,())" to
     avoid this warning.

 "use" not allowed in expression
     (F) The "use" keyword is recognized and executed at compile time, and
     returns no useful value.  See perlmod.

 Use of @_ in %s with signatured subroutine is experimental
     (S experimental::args_array_with_signatures) An expression involving
     the @_ arguments array was found in a subroutine that uses a
     signature.  This is experimental because the interaction between the
     arguments array and parameter handling via signatures is not
     guaranteed to remain stable in any future version of Perl, and such
     code should be avoided.

 Use of bare << to mean <<"" is forbidden
     (F) You are now required to use the explicitly quoted form if you
     wish to use an empty line as the terminator of the here-document.

     Use of a bare terminator was deprecated in Perl 5.000, and is a fatal
     error as of Perl 5.28.

 Use of /c modifier is meaningless in s///
     (W regexp) You used the /c modifier in a substitution.  The /c
     modifier is not presently meaningful in substitutions.

 Use of /c modifier is meaningless without /g
     (W regexp) You used the /c modifier with a regex operand, but didn't
     use the /g modifier.  Currently, /c is meaningful only when /g is
     used.  (This may change in the future.)

 Use of code point 0x%s is not allowed; the permissible max is 0x%X
 Use of code point 0x%s is not allowed; the permissible max is 0x%X in
 regex; marked by <-- HERE in m/%s/
     (F) You used a code point that is not allowed, because it is too
     large.  Unicode only allows code points up to 0x10FFFF, but Perl
     allows much larger ones. Earlier versions of Perl allowed code points
     above IV_MAX (0x7FFFFFF on 32-bit platforms, 0x7FFFFFFFFFFFFFFF on
     64-bit platforms), however, this could possibly break the perl
     interpreter in some constructs, including causing it to hang in a few
     cases.

     If your code is to run on various platforms, keep in mind that the
     upper limit depends on the platform.  It is much larger on 64-bit
     word sizes than 32-bit ones.

     The use of out of range code points was deprecated in Perl 5.24, and
     became a fatal error in Perl 5.28.

 Use of eeaacchh(()) on hash after insertion without resetting hash iterator
 results in undefined behavior
     (S internal) The behavior of "each()" after insertion is undefined;
     it may skip items, or visit items more than once.  Consider using
     "keys()" instead of "each()".

 Use of := for an empty attribute list is not allowed
     (F) The construction "my $x := 42" used to parse as equivalent to "my
     $x : = 42" (applying an empty attribute list to $x).  This construct
     was deprecated in 5.12.0, and has now been made a syntax error, so
     ":=" can be reclaimed as a new operator in the future.

     If you need an empty attribute list, for example in a code generator,
     add a space before the "=".

 Use of %s for non-UTF-8 locale is wrong.  Assuming a UTF-8 locale
     (W locale)  You are matching a regular expression using locale rules,
     and the specified construct was encountered.  This construct is only
     valid for UTF-8 locales, which the current locale isn't.  This
     doesn't make sense.  Perl will continue, assuming a Unicode (UTF-8)
     locale, but the results are likely to be wrong.

 Use of freed value in iteration
     (F) Perhaps you modified the iterated array within the loop?  This
     error is typically caused by code like the following:

         @a = (3,4);
         @a = () for (1,2,@a);

     You are not supposed to modify arrays while they are being iterated
     over.  For speed and efficiency reasons, Perl internally does not do
     full reference-counting of iterated items, hence deleting such an
     item in the middle of an iteration causes Perl to see a freed value.

 Use of /g modifier is meaningless in split
     (W regexp) You used the /g modifier on the pattern for a "split"
     operator.  Since "split" always tries to match the pattern
     repeatedly, the "/g" has no effect.

 Use of "goto" to jump into a construct is deprecated
     (D deprecated) Using "goto" to jump from an outer scope into an inner
     scope is deprecated and should be avoided.

     This was deprecated in Perl 5.12.

 Use of '%s' in \p{} or \P{} is deprecated because: %s
     (D deprecated) Certain properties are deprecated by Unicode, and may
     eventually be removed from the Standard, at which time Perl will
     follow along.  In the meantime, this message is raised to notify you.

 Use of inherited AUTOLOAD for non-method %s::%s() is no longer allowed
     (F) As an accidental feature, "AUTOLOAD" subroutines were looked up
     as methods (using the @ISA hierarchy), even when the subroutines to
     be autoloaded were called as plain functions (e.g. "Foo::bar()"), not
     as methods (e.g. "Foo->bar()" or "$obj->bar()").

     This was deprecated in Perl 5.004, and was made fatal in Perl 5.28.

 Use of %s in printf format not supported
     (F) You attempted to use a feature of printf that is accessible from
     only C.  This usually means there's a better way to do it in Perl.

 Use of '%s' is deprecated as a string delimiter
     (D deprecated) You used the given character as a starting delimiter
     of a string outside the scope of
     "use feature 'extra_paired_delimiters'".  This character is the
     mirror image of another Unicode character; within the scope of that
     feature, the two are considered a pair for delimitting strings.  It
     is planned to make that feature the default, at which point this
     usage would become illegal; hence this warning.

     For now, you may live with this warning, or turn it off, but this
     code will no longer compile in a future version of Perl.  Or you can
     turn on "use feature 'extra_paired_delimiters'" and use the character
     that is the mirror image of this one for the closing string
     delimiter.

 Use of '%s' is experimental as a string delimiter
     (S experimental::extra_paired_delimiters)   This warning is emitted
     if you use as a string delimiter one of the non-ASCII mirror image
     ones enabled by "use feature 'extra_paired_delimiters'".  Simply
     suppress the warning if you want to use the feature, but know that in
     doing so you are taking the risk of using an experimental feature
     which may change or be removed in a future Perl version:

 Use of %s is not allowed in Unicode property wildcard subpatterns in
 regex; marked by <-- HERE in m/%s/
     (F) You were using a wildcard subpattern a Unicode property value,
     and the subpattern contained something that is illegal.  Not all
     regular expression capabilities are legal in such subpatterns, and
     this is one.  Rewrite your subppattern to not use the offending
     construct.  See "Wildcards in Property Values" in perlunicode.

 Use of -l on filehandle%s
     (W io) A filehandle represents an opened file, and when you opened
     the file it already went past any symlink you are presumably trying
     to look for.  The operation returned "undef".  Use a filename
     instead.

 Use of reference "%s" as array index
     (W misc) You tried to use a reference as an array index; this
     probably isn't what you mean, because references in numerical context
     tend to be huge numbers, and so usually indicates programmer error.

     If you really do mean it, explicitly numify your reference, like so:
     $array[0+$ref].  This warning is not given for overloaded objects,
     however, because you can overload the numification and
     stringification operators and then you presumably know what you are
     doing.

 Use of strings with code points over 0xFF as arguments to %s operator is
 not allowed
     (F) You tried to use one of the string bitwise operators ("&" or "|"
     or "^" or "~") on a string containing a code point over 0xFF.  The
     string bitwise operators treat their operands as strings of bytes,
     and values beyond 0xFF are nonsensical in this context.

     Certain instances became fatal in Perl 5.28; others in perl 5.32.

 Use of strings with code points over 0xFF as arguments to vec is
 forbidden
     (F) You tried to use "vec" on a string containing a code point over
     0xFF, which is nonsensical here.

     This became fatal in Perl 5.32.

 Use of tainted arguments in %s is deprecated
     (W taint, deprecated) You have supplied "system()" or "exec()" with
     multiple arguments and at least one of them is tainted.  This used to
     be allowed but will become a fatal error in a future version of perl.
     Untaint your arguments.  See perlsec.

 Use of unassigned code point or non-standalone grapheme for a delimiter
 is not allowed
     (F) A grapheme is what appears to a native-speaker of a language to
     be a character.  In Unicode (and hence Perl) a grapheme may actually
     be several adjacent characters that together form a complete
     grapheme.  For example, there can be a base character, like "R" and
     an accent, like a circumflex "^", that appear when displayed to be a
     single character with the circumflex hovering over the "R".  Perl
     currently allows things like that circumflex to be delimiters of
     strings, patterns, _e_t_c.  When displayed, the circumflex would look
     like it belongs to the character just to the left of it.  In order to
     move the language to be able to accept graphemes as delimiters, we
     cannot allow the use of delimiters which aren't graphemes by
     themselves.  Also, a delimiter must already be assigned (or known to
     be never going to be assigned) to try to future-proof code, for
     otherwise code that works today would fail to compile if the
     currently unassigned delimiter ends up being something that isn't a
     stand-alone grapheme.  Because Unicode is never going to assign non-
     character code points, nor code points that are above the legal
     Unicode maximum, those can be delimiters, and their use is legal.

 Use of uninitialized value%s
     (W uninitialized) An undefined value was used as if it were already
     defined.  It was interpreted as a "" or a 0, but maybe it was a
     mistake.  To suppress this warning assign a defined value to your
     variables.

     To help you figure out what was undefined, perl will try to tell you
     the name of the variable (if any) that was undefined.  In some cases
     it cannot do this, so it also tells you what operation you used the
     undefined value in.  Note, however, that perl optimizes your program
     and the operation displayed in the warning may not necessarily appear
     literally in your program.  For example, "that $foo" is usually
     optimized into ""that " . $foo", and the warning will refer to the
     "concatenation (.)" operator, even though there is no "." in your
     program.

 "use re 'strict'" is experimental
     (S experimental::re_strict) The things that are different when a
     regular expression pattern is compiled under 'strict' are subject to
     change in future Perl releases in incompatible ways.  This means that
     a pattern that compiles today may not in a future Perl release.  This
     warning is to alert you to that risk.

 Use \x{...} for more than two hex characters in regex; marked by <-- HERE
 in m/%s/
     (F) In a regular expression, you said something like

      (?[ [ \xBEEF ] ])

     Perl isn't sure if you meant this

      (?[ [ \x{BEEF} ] ])

     or if you meant this

      (?[ [ \x{BE} E F ] ])

     You need to add either braces or blanks to disambiguate.

 Using just the first character returned by \N{} in character class in
 regex; marked by <-- HERE in m/%s/
     (W regexp) Named Unicode character escapes "(\N{...})" may return a
     multi-character sequence.  Even though a character class is supposed
     to match just one character of input, perl will match the whole thing
     correctly, except when the class is inverted ("[^...]"), or the
     escape is the beginning or final end point of a range.  For these,
     what should happen isn't clear at all.  In these circumstances, Perl
     discards all but the first character of the returned sequence, which
     is not likely what you want.

 Using just the single character results returned by \p{} in (?[...]) in
 regex; marked by <-- HERE in m/%s/
     (W regexp) Extended character classes currently cannot handle
     operands that evaluate to more than one character.  These are removed
     from the results of the expansion of the "\p{}".

     This situation can happen, for example, in

      (?[ \p{name=/KATAKANA/} ])

     "KATAKANA LETTER AINU P" is a legal Unicode name (technically a
     "named sequence"), but it is actually two characters.  The above
     expression with match only the Unicode names containing KATAKANA that
     represent single characters.

 Using /u for '%s' instead of /%s in regex; marked by <-- HERE in m/%s/
     (W regexp) You used a Unicode boundary ("\b{...}" or "\B{...}") in a
     portion of a regular expression where the character set modifiers
     "/a" or "/aa" are in effect.  These two modifiers indicate an ASCII
     interpretation, and this doesn't make sense for a Unicode definition.
     The generated regular expression will compile so that the boundary
     uses all of Unicode.  No other portion of the regular expression is
     affected.

 Using !~ with %s doesn't make sense
     (F) Using the "!~" operator with "s///r", "tr///r" or "y///r" is
     currently reserved for future use, as the exact behavior has not been
     decided.  (Simply returning the boolean opposite of the modified
     string is usually not particularly useful.)

 UTF-16 surrogate U+%X
     (S surrogate) You had a UTF-16 surrogate in a context where they are
     not considered acceptable.  These code points, between U+D800 and
     U+DFFF (inclusive), are used by Unicode only for UTF-16.  However,
     Perl internally allows all unsigned integer code points (up to the
     size limit available on your platform), including surrogates.  But
     these can cause problems when being input or output, which is likely
     where this message came from.  If you really really know what you are
     doing you can turn off this warning by "no warnings 'surrogate';".

 Value of %s can be "0"; test with ddeeffiinneedd(())
     (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
     "each()", or "readdir()" as a boolean value.  Each of these
     constructs can return a value of "0"; that would make the conditional
     expression false, which is probably not what you intended.  When
     using these constructs in conditional expressions, test their values
     with the "defined" operator.

 Value of CLI symbol "%s" too long
     (W misc) A warning peculiar to VMS.  Perl tried to read the value of
     an %ENV element from a CLI symbol table, and found a resultant string
     longer than 1024 characters.  The return value has been truncated to
     1024 characters.

 Variable "%s" is not available
     (W closure) During compilation, an inner named subroutine or eval is
     attempting to capture an outer lexical that is not currently
     available.  This can happen for one of two reasons.  First, the outer
     lexical may be declared in an outer anonymous subroutine that has not
     yet been created.  (Remember that named subs are created at compile
     time, while anonymous subs are created at run-time.)  For example,

         sub { my $a; sub f { $a } }

     At the time that f is created, it can't capture the current value of
     $a, since the anonymous subroutine hasn't been created yet.
     Conversely, the following won't give a warning since the anonymous
     subroutine has by now been created and is live:

         sub { my $a; eval 'sub f { $a }' }->();

     The second situation is caused by an eval accessing a variable that
     has gone out of scope, for example,

         sub f {
             my $a;
             sub { eval '$a' }
         }
         f()->();

     Here, when the '$a' in the eval is being compiled, f() is not
     currently being executed, so its $a is not available for capture.

 Variable "%s" is not imported%s
     (S misc) With "use strict" in effect, you referred to a global
     variable that you apparently thought was imported from another
     module, because something else of the same name (usually a
     subroutine) is exported by that module.  It usually means you put the
     wrong funny character on the front of your variable. It is also
     possible you used an "our" variable whose scope has ended.

 Variable length lookbehind not implemented in regex m/%s/
     (F) TThhiiss mmeessssaaggee nnoo lloonnggeerr sshhoouulldd bbee rraaiisseedd aass ooff PPeerrll 55..3300..  It is
     retained in this document as a convenience for people using an
     earlier Perl version.

     In Perl 5.30 and earlier, lookbehind is allowed only for
     subexpressions whose length is fixed and known at compile time.  For
     positive lookbehind, you can use the "\K" regex construct as a way to
     get the equivalent functionality.  See (?<=pattern) and \K in perlre.

     Starting in Perl 5.18, there are non-obvious Unicode rules under "/i"
     that can match variably, but which you might not think could.  For
     example, the substring "ss" can match the single character LATIN
     SMALL LETTER SHARP S.  Here's a complete list of the current ones
     affecting ASCII characters:

ASCII #

       sequence      Matches single letter under /i

FF U+FB00 LATIN SMALL LIGATURE FF #

FFI U+FB03 LATIN SMALL LIGATURE FFI #

FFL U+FB04 LATIN SMALL LIGATURE FFL #

FI U+FB01 LATIN SMALL LIGATURE FI #

FL U+FB02 LATIN SMALL LIGATURE FL #

SS U+00DF LATIN SMALL LETTER SHARP S #

U+1E9E LATIN CAPITAL LETTER SHARP S #

ST U+FB06 LATIN SMALL LIGATURE ST #

U+FB05 LATIN SMALL LIGATURE LONG S T #

     This list is subject to change, but is quite unlikely to.  Each ASCII
     sequence can be any combination of upper- and lowercase.

     You can avoid this by using a bracketed character class in the
     lookbehind assertion, like

      (?<![sS]t)
      (?<![fF]f[iI])

     This fools Perl into not matching the ligatures.

     Another option for Perls starting with 5.16, if you only care about
     ASCII matches, is to add the "/aa" modifier to the regex.  This will
     exclude all these non-obvious matches, thus getting rid of this
     message.  You can also say

      use if $] ge 5.016, re => '/aa';

     to apply "/aa" to all regular expressions compiled within its scope.
     See re.

 Variable length positive lookbehind with capturing is experimental in
 regex m/%s/
     (W) Variable length positive lookbehind with capturing is not well
     defined. This warning alerts you to the fact that you are using a
     construct which may change in a future version of perl. See the
     documentation of Positive Lookbehind in perlre for details. You may
     silence this warning with the following:

         no warnings 'experimental::vlb';

 Variable length negative lookbehind with capturing is experimental in
 regex m/%s/
     (W) Variable length negative lookbehind with capturing is not well
     defined. This warning alerts you to the fact that you are using a
     construct which may change in a future version of perl. See the
     documentation of Negative Lookbehind in perlre for details. You may
     silence this warning with the following:

         no warnings 'experimental::vlb';

 "%s" variable %s masks earlier declaration in same %s
     (W shadow) A "my", "our" or "state" variable has been redeclared in
     the current scope or statement, effectively eliminating all access to
     the previous instance.  This is almost always a typographical error.
     Note that the earlier variable will still exist until the end of the
     scope or until all closure references to it are destroyed.

 Variable syntax
     (A) You've accidentally run your script through ccsshh instead of Perl.
     Check the #! line, or manually feed your script into Perl yourself.

 Variable "%s" will not stay shared
     (W closure) An inner (nested) _n_a_m_e_d subroutine is referencing a
     lexical variable defined in an outer named subroutine.

     When the inner subroutine is called, it will see the value of the
     outer subroutine's variable as it was before and during the *first*
     call to the outer subroutine; in this case, after the first call to
     the outer subroutine is complete, the inner and outer subroutines
     will no longer share a common value for the variable.  In other
     words, the variable will no longer be shared.

     This problem can usually be solved by making the inner subroutine
     anonymous, using the "sub {}" syntax.  When inner anonymous subs that
     reference variables in outer subroutines are created, they are
     automatically rebound to the current values of such variables.

 vector argument not supported with alpha versions
     (S printf) The %vd (s)printf format does not support version objects
     with alpha parts.

 Verb pattern '%s' has a mandatory argument in regex; marked by <-- HERE
 in m/%s/
     (F) You used a verb pattern that requires an argument.  Supply an
     argument or check that you are using the right verb.

 Verb pattern '%s' may not have an argument in regex; marked by <-- HERE
 in m/%s/
     (F) You used a verb pattern that is not allowed an argument.  Remove
     the argument or check that you are using the right verb.

 Version control conflict marker
     (F) The parser found a line starting with "<<<<<<<", ">>>>>>>", or
     "=======".  These may be left by a version control system to mark
     conflicts after a failed merge operation.

 Version number must be a constant number
     (P) The attempt to translate a "use Module n.n LIST" statement into
     its equivalent "BEGIN" block found an internal inconsistency with the
     version number.

 Version string '%s' contains invalid data; ignoring: '%s'
     (W misc) The version string contains invalid characters at the end,
     which are being ignored.

 Warning: something's wrong
     (W) You passed wwaarrnn(()) an empty string (the equivalent of "warn """)
     or you called it with no args and $@ was empty.

 Warning: unable to close filehandle %s properly
     (S) The implicit cclloossee(()) done by an ooppeenn(()) got an error indication on
     the cclloossee(()).  This usually indicates your file system ran out of disk
     space.

 Warning: unable to close filehandle properly: %s
 Warning: unable to close filehandle %s properly: %s
     (S io) There were errors during the implicit cclloossee(()) done on a
     filehandle when its reference count reached zero while it was still
     open, e.g.:

         {
             open my $fh, '>', $file  or die "open: '$file': $!\n";
             print $fh $data or die "print: $!";
         } # implicit close here

     Because various errors may only be detected by cclloossee(()) (e.g.
     buffering could allow the "print" in this example to return true even
     when the disk is full), it is dangerous to ignore its result.  So
     when it happens implicitly, perl will signal errors by warning.

     PPrriioorr ttoo vveerrssiioonn 55..2222..00,, ppeerrll iiggnnoorreedd ssuucchh eerrrroorrss, so the common
     idiom shown above was liable to cause ssiilleenntt ddaattaa lloossss.

 Warning: Use of "%s" without parentheses is ambiguous
     (S ambiguous) You wrote a unary operator followed by something that
     looks like a binary operator that could also have been interpreted as
     a term or unary operator.  For instance, if you know that the rand
     function has a default argument of 1.0, and you write

         rand + 5;

     you may THINK you wrote the same thing as

         rand() + 5;

     but in actual fact, you got

         rand(+5);

     So put in parentheses to say what you really mean.

 when is experimental
     (S experimental::smartmatch) "when" depends on smartmatch, which is
     experimental.  Additionally, it has several special cases that may
     not be immediately obvious, and their behavior may change or even be
     removed in any future release of perl.  See the explanation under
     "Experimental Details on given and when" in perlsyn.

 Wide character in %s
     (S utf8) Perl met a wide character (ordinal >255) when it wasn't
     expecting one.  This warning is by default on for I/O (like print).

     If this warning does come from I/O, the easiest way to quiet it is
     simply to add the ":utf8" layer, _e_._g_., "binmode STDOUT, ':utf8'".
     Another way to turn off the warning is to add "no warnings 'utf8';"
     but that is often closer to cheating.  In general, you are supposed
     to explicitly mark the filehandle with an encoding, see open and
     "binmode" in perlfunc.

     If the warning comes from other than I/O, this diagnostic probably
     indicates that incorrect results are being obtained.  You should
     examine your code to determine how a wide character is getting to an
     operation that doesn't handle them.

 Wide character (U+%X) in %s
     (W locale) While in a single-byte locale (_i_._e_., a non-UTF-8 one), a
     multi-byte character was encountered.   Perl considers this character
     to be the specified Unicode code point.  Combining non-UTF-8 locales
     and Unicode is dangerous.  Almost certainly some characters will have
     two different representations.  For example, in the ISO 8859-7
     (Greek) locale, the code point 0xC3 represents a Capital Gamma.  But
     so also does 0x393.  This will make string comparisons unreliable.

     You likely need to figure out how this multi-byte character got mixed
     up with your single-byte locale (or perhaps you thought you had a
     UTF-8 locale, but Perl disagrees).

 Within []-length '%c' not allowed
     (F) The count in the (un)pack template may be replaced by
     "[TEMPLATE]" only if "TEMPLATE" always matches the same amount of
     packed bytes that can be determined from the template alone.  This is
     not possible if it contains any of the codes @, /, U, u, w or a
     *-length.  Redesign the template.

 While trying to resolve method call %s->%s() can not locate package "%s"
 yet it is mentioned in @%s::ISA (perhaps you forgot to load "%s"?)
     (W syntax) It is possible that the @ISA contains a misspelled or
     never loaded package name, which can result in perl choosing an
     unexpected parent class's method to resolve the method call. If this
     is deliberate you can do something like

       @Missing::Package::ISA = ();

     to silence the warnings, otherwise you should correct the package
     name, or ensure that the package is loaded prior to the method call.

 %s() with negative argument
     (S misc) Certain operations make no sense with negative arguments.
     Warning is given and the operation is not done.

 wwrriittee(()) on closed filehandle %s
     (W closed) The filehandle you're writing to got itself closed
     sometime before now.  Check your control flow.

 %s "\x%X" does not map to Unicode
     (S utf8) When reading in different encodings, Perl tries to map
     everything into Unicode characters.  The bytes you read in are not
     legal in this encoding.  For example

         utf8 "\xE4" does not map to Unicode

     if you try to read in the a-diaereses Latin-1 as UTF-8.

 'X' outside of string
     (F) You had a (un)pack template that specified a relative position
     before the beginning of the string being (un)packed.  See "pack" in
     perlfunc.

 'x' outside of string in unpack
     (F) You had a pack template that specified a relative position after
     the end of the string being unpacked.  See "pack" in perlfunc.

YOU HAVEN’T DISABLED SET-ID SCRIPTS IN THE KERNEL YET! #

     (F) And you probably never will, because you probably don't have the
     sources to your kernel, and your vendor probably doesn't give a rip
     about what you want.  There is a vulnerability anywhere that you have
     a set-id script, and to close it you need to remove the set-id bit
     from the script that you're attempting to run.  To actually run the
     script set-id, your best bet is to put a set-id C wrapper around your
     script.

 You need to quote "%s"
     (W syntax) You assigned a bareword as a signal handler name.
     Unfortunately, you already have a subroutine of that name declared,
     which means that Perl 5 will try to call the subroutine when the
     assignment is executed, which is probably not what you want.  (If it
     IS what you want, put an & in front.)

 Your random numbers are not that random
     (F) When trying to initialize the random seed for hashes, Perl could
     not get any randomness out of your system.  This usually indicates
     Something Very Wrong.

 Zero length \N{} in regex; marked by <-- HERE in m/%s/
     (F) Named Unicode character escapes ("\N{...}") may return a zero-
     length sequence.  Such an escape was used in an extended character
     class, i.e.  "(?[...])", or under "use re 'strict'", which is not
     permitted.  Check that the correct escape has been used, and the
     correct charnames handler is in scope.  The <-- HERE shows
     whereabouts in the regular expression the problem was discovered.

SSEEEE AALLSSOO #

 warnings, diagnostics.

perl v5.36.3 2023-02-15 PERLDIAG(1)