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

INTERNALS(1) Perl Programmers Reference Guide INTERNALS(1)

NNAAMMEE #

 Internals - Reserved special namespace for internals related functions

SSYYNNOOPPSSIISS #

     $is_ro= Internals::SvREADONLY($x)
     $refcnt= Internals::SvREFCNT($x)
     hv_clear_placeholders(%hash);

DDEESSCCRRIIPPTTIIOONN #

 The Internals namespace is used by the core Perl development team to
 expose certain low level internals routines for testing and other
 purposes.

 In theory these routines were not and are not intended to be used outside
 of the perl core, and are subject to change and removal at any time.

 In practice people have come to depend on these over the years, despite
 being historically undocumented, so we will provide some level of forward
 compatibility for some time. Nevertheless you can assume that any routine
 documented here is experimental or deprecated and you should find
 alternatives to their use.

FFUUNNCCTTIIOONNSS #

 SvREFCNT(THING [, $value])
     Historically Perl has been a refcounted language. This means that
     each variable tracks how many things reference it, and when the
     variable is no longer referenced it will automatically free itself.
     In theory Perl code should not have to care about this, and in a
     future version Perl might change to some other strategy, although in
     practice this is unlikely.

     This function allows one to violate the abstraction of variables and
     get or set the refcount of a variable, and in generally is really
     only useful in code that is testing refcount behavior.

     *NOTE* You are strongly discouraged from using this function in non-
     test code and especially discouraged from using the set form of this
     function.  The results of doing so may result in segmentation faults
     or other undefined behavior.

 SvREADONLY(THING, [, $value])
     Set or get whether a variable is readonly or not. Exactly what the
     readonly flag means depend on the type of the variable affected and
     the version of perl used.

     You are strongly discouraged from using this function directly. It is
     used by various core modules, like "Hash::Util", and the "constant"
     pragma to implement higher-level behavior which should be used
     instead.

     See the core implementation for the exact meaning of the readonly
     flag for each internal variable type.

 hv_clear_placeholders(%hash)
     Clear any placeholders from a locked hash. Should not be used
     directly.  You should use the wrapper functions provided by
     Hash::Util instead.  As of 5.25 also available as "
     Hash::Util::_clear_placeholders(%hash) "

AAUUTTHHOORR #

 Perl core development team.

SSEEEE AALLSSOO #

 perlguts Hash::Util constant universal.c

perl v5.36.3 2019-12-30 INTERNALS(1)