Devel::bt(3pm)						User Contributed Perl Documentation					    Devel::bt(3pm)

NAME

       Devel::bt - Automatic gdb backtraces on errors

SYNOPSIS

	   $ perl -d:bt -MB -e'(bless (my $o = 0), q{B::SV})->REFCNT'
	   #0  0x00007f9c3215ab0e in __libc_waitpid (pid=<value optimized out>, stat_loc=0x7fff4c5ffbe8, options=<value optimized out>) at ../sysdeps/unix/sysv/linux/waitpid.c:32
	   #1  0x00007f9c319168c1 in backtrace () at bt.xs:129
	   #2  0x00007f9c319168ec in sighandler (sig=11) at bt.xs:135
	   #3  <signal handler called>
	   #4  0x00007f9c316c8ccf in XS_B__SV_REFCNT (my_perl=0x151c010, cv=0x177bfb8) at B.c:3360
	   #5  0x000000000057d5a0 in Perl_pp_entersub (my_perl=0x151c010) at pp_hot.c:2882
	   #6  0x000000000051a331 in Perl_runops_debug (my_perl=0x151c010) at dump.c:2049
	   #7  0x0000000000454ab0 in S_run_body (my_perl=0x151c010, oldscope=1) at perl.c:2308
	   #8  0x0000000000453d78 in perl_run (my_perl=0x151c010) at perl.c:2233
	   #9  0x00000000004230fd in main (argc=6, argv=0x7fff4c600788, env=0x7fff4c6007c0) at perlmain.c:117

DESCRIPTION

       This module, when enabled, registers a handler for certain types of fatal errors, like segmentation faults, and, once such an error occurs,
       prints a debugger backtrace to standard output before exiting the program.

       It is intended to be used to debug crashes in situations where running the failing program directly under a debugger is not possible, for
       example when trying to get more information from cpantesters or from users unfamiliar with gdb.

HOW IT WORKS

       When being imported, a signal handler for the following signals is registered:

       o   "SIGILL"

       o   "SIGFPE"

       o   "SIGBUS"

       o   "SIGSEGV"

       o   "SIGTRAP"

       o   "SIGABRT"

       o   "SIGQUIT"

       Once the program causes an error that results in one of the above signals being sent to it, the signal handler will be called, and fork off
       a process running "gdb" and generating a backtrace of the running program, which will then be printed to standard output.

ACKNOWLEDGEMENTS

       This software is based on parts of "glib", which is written by:

       o   Peter Mattis <petm@xcf.berkeley.edu>

       o   Spencer Kimball <spencer@xcf.berkeley.edu>

       o   Josh MacDonald <jmacd@xcf.berkeley.edu>

       o   Shawn T. Amundson <amundson@gimp.org>

       o   Jeff Garzik <jgarzik@pobox.com>

       o   Raja R Harinath <harinath@cs.umn.edu>

       o   Tim Janik <timj@gtk.org>

       o   Elliot Lee <sopwith@redhat.com>

       o   Tor Lillqvist <tml@iki.fi>

       o   Paolo Molaro <lupus@debian.org>

       o   Havoc Pennington <hp@pobox.com>

       o   Manish Singh <yosh@gimp.org>

       o   Owen Taylor <otaylor@gtk.org>

       o   Sebastian Wilhelmi <wilhelmi@ira.uka.de>

       o   and others

       "glib" is licensed under The GNU Lesser General Public License, Version 2.

AUTHOR

       Florian Ragwitz <rafl@debian.org>

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2010 by Florian Ragwitz.

       This is free software, licensed under:

	 The GNU Lesser General Public License, Version 2.1, February 1999

perl v5.14.2							    2010-09-08							    Devel::bt(3pm)