NAME

Debug::DumpCore - Generate a SegFault

SYNOPSIS

            

              
              
use Debug::DumpCore;
Debug::DumpCore::segv();
            
          

DESCRIPTION

This module implements a buggy C function which tries to dereference a NULL pointer, which generates a SEGFAULT. It is used to test the Debug::FaultAutoBT module that attempts to automatically generate a backtrace when some fatal signal is delivered, without needing the core file.

Notice that you could use Perl's CORE::dump to achieve the same goal, but dump()'s backtrace is not very useful for teaching purposes. Debug::DumpCore::segv() calls another proper C function which finally calls a buggy C function, which causes a SEGFAULT. So you get a long trace. For example this is the backtrace generated on my machine:

            

              
              
#0  0x402b979b in crash_now_for_real (
    suicide_message=0x402ba040 "Cannot stand this life anymore")
    at DumpCore.xs:246
#1  0x402b97bd in crash_now (
    suicide_message=0x402ba040 "Cannot stand this life anymore",
    attempt_num=42) at FaultAutoBT.xs:253
#2  0x402b983e in XS_Debug__DumpCore_segv (cv=0x81751e4)
    at FaultAutoBT.xs:262
#3  0x400851ec in Perl_pp_entersub ()
   from /usr/lib/perl5/5.6.1/i386-linux/CORE/libperl.so
            
          

And the corresponding C code around line 246 is:

            

              
              
 7:  crash_now_for_real(char *suicide_message)
 8:  {
 9:      int *p = NULL;
10:      printf("%d", *p); /* cause a segfault */
            
          

EXPORT

None.

AUTHOR

Stas Bekman <stas@stason.org>

SEE ALSO

perl(3), Debug::FaultAutoBT(3).