sigtrap(3p) Perl Programmers Reference Guide sigtrap(3p) #

sigtrap(3p) Perl Programmers Reference Guide sigtrap(3p)

NNAAMMEE #

 sigtrap - Perl pragma to enable simple signal handling

SSYYNNOOPPSSIISS #

     use sigtrap;
     use sigtrap qw(stack-trace old-interface-signals);  # equivalent
     use sigtrap qw(BUS SEGV PIPE ABRT);
     use sigtrap qw(die INT QUIT);
     use sigtrap qw(die normal-signals);
     use sigtrap qw(die untrapped normal-signals);
     use sigtrap qw(die untrapped normal-signals
                     stack-trace any error-signals);
     use sigtrap 'handler' => \&my_handler, 'normal-signals';
     use sigtrap qw(handler my_handler normal-signals
                     stack-trace error-signals);

DDEESSCCRRIIPPTTIIOONN #

 The ssiiggttrraapp pragma is a simple interface to installing signal handlers.
 You can have it install one of two handlers supplied by ssiiggttrraapp itself
 (one which provides a Perl stack trace and one which simply "die()"s), or
 alternately you can supply your own handler for it to install.  It can be
 told only to install a handler for signals which are either untrapped or
 ignored.  It has three lists of signals to trap, plus you can supply your
 own list of signals.

 The arguments passed to the "use" statement which invokes ssiiggttrraapp are
 processed in order.  When a signal name or the name of one of ssiiggttrraapp's
 signal lists is encountered a handler is immediately installed, when an
 option is encountered it affects subsequently installed handlers.

OOPPTTIIOONNSS #

SSIIGGNNAALL HHAANNDDLLEERRSS #

 These options affect which handler will be used for subsequently
 installed signals.

 ssttaacckk--ttrraaccee
     The handler used for subsequently installed signals outputs a Perl
     stack trace to STDERR and then tries to dump core.  This is the
     default signal handler.

 ddiiee The handler used for subsequently installed signals calls "die"
     (actually "croak") with a message indicating which signal was caught.

 hhaannddlleerr _y_o_u_r_-_h_a_n_d_l_e_r
     _y_o_u_r_-_h_a_n_d_l_e_r will be used as the handler for subsequently installed
     signals.  _y_o_u_r_-_h_a_n_d_l_e_r can be any value which is valid as an
     assignment to an element of %SIG. See perlvar for examples of handler
     functions.

SSIIGGNNAALL LLIISSTTSS #

 ssiiggttrraapp has a few built-in lists of signals to trap.  They are:

 nnoorrmmaall--ssiiggnnaallss
     These are the signals which a program might normally expect to
     encounter and which by default cause it to terminate.  They are HUP,
     INT, PIPE and TERM.

 eerrrroorr--ssiiggnnaallss
     These signals usually indicate a serious problem with the Perl
     interpreter or with your script.  They are ABRT, BUS, EMT, FPE, ILL,
     QUIT, SEGV, SYS and TRAP.

 oolldd--iinntteerrffaaccee--ssiiggnnaallss
     These are the signals which were trapped by default by the old
     ssiiggttrraapp interface, they are ABRT, BUS, EMT, FPE, ILL, PIPE, QUIT,
     SEGV, SYS, TERM, and TRAP.  If no signals or signals lists are passed
     to ssiiggttrraapp, this list is used.

 For each of these three lists, the collection of signals set to be
 trapped is checked before trapping; if your architecture does not
 implement a particular signal, it will not be trapped but rather silently
 ignored.

OOTTHHEERR #

 uunnttrraappppeedd
     This token tells ssiiggttrraapp to install handlers only for subsequently
     listed signals which aren't already trapped or ignored.

 aannyy This token tells ssiiggttrraapp to install handlers for all subsequently
     listed signals.  This is the default behavior.

 _s_i_g_n_a_l
     Any argument which looks like a signal name (that is,
     "/^[A-Z][A-Z0-9]*$/") indicates that ssiiggttrraapp should install a handler
     for that name.

 _n_u_m_b_e_r
     Require that at least version _n_u_m_b_e_r of ssiiggttrraapp is being used.

EEXXAAMMPPLLEESS #

 Provide a stack trace for the old-interface-signals:

     use sigtrap;

 Ditto:

     use sigtrap qw(stack-trace old-interface-signals);

 Provide a stack trace on the 4 listed signals only:

     use sigtrap qw(BUS SEGV PIPE ABRT);

 Die on INT or QUIT:

     use sigtrap qw(die INT QUIT);

 Die on HUP, INT, PIPE or TERM:

     use sigtrap qw(die normal-signals);

 Die on HUP, INT, PIPE or TERM, except don't change the behavior for
 signals which are already trapped or ignored:

     use sigtrap qw(die untrapped normal-signals);

 Die on receipt one of any of the nnoorrmmaall--ssiiggnnaallss which is currently
 uunnttrraappppeedd, provide a stack trace on receipt of aannyy of the eerrrroorr--ssiiggnnaallss:

     use sigtrap qw(die untrapped normal-signals
                     stack-trace any error-signals);

 Install mmyy__hhaannddlleerr(()) as the handler for the nnoorrmmaall--ssiiggnnaallss:

     use sigtrap 'handler', \&my_handler, 'normal-signals';

 Install mmyy__hhaannddlleerr(()) as the handler for the normal-signals, provide a
 Perl stack trace on receipt of one of the error-signals:

     use sigtrap qw(handler my_handler normal-signals
                     stack-trace error-signals);

perl v5.36.3 2023-02-15 sigtrap(3p)