sigtrap

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

NAME
       sigtrap - Perl pragma to enable simple signal handling

SYNOPSIS
           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);

DESCRIPTION
       The sigtrap pragma is a simple interface to installing signal handlers.
       You can have it install one of two handlers supplied by sigtrap 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 a couple of lists of signals to trap,
       plus you can supply your own list of signals.

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

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

       stack-trace
           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.

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

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

   SIGNAL LISTS
       sigtrap has a few built-in lists of signals to trap.  They are:

       normal-signals
           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.

       error-signals
           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.

       old-interface-signals
           These are the signals which were trapped by default by the old
           sigtrap interface, they are ABRT, BUS, EMT, FPE, ILL, PIPE, QUIT,
           SEGV, SYS, TERM, and TRAP.  If no signals or signals lists are
           passed to sigtrap, 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.

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

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

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

       number
           Require that at least version number of sigtrap is being used.

EXAMPLES
       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 an of the normal-signals which is currently
       untrapped, provide a stack trace on receipt of any of the error-
       signals:

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

       Install my_handler() as the handler for the normal-signals:

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

       Install my_handler() 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 v5.30.0                      2023-11-23                    sigtrap(3perl)