GDB, the GNU Project debugger, allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed.
cli/ config/ doc/ features/ gdbserver/ gdbtk/ mi/ osf-share/ po/ regformats/ signals/ testsuite/ tui/ CONTRIBUTE COPYING ChangeLog ChangeLog-1990 ChangeLog-1991 ChangeLog-1992 ChangeLog-1993 ChangeLog-1994 ChangeLog-1995 ChangeLog-1996 ChangeLog-1997 ChangeLog-1998 ChangeLog-1999 ChangeLog-2000 ChangeLog-2001 ChangeLog-2002 ChangeLog-2003 ChangeLog-2004 ChangeLog-2005 ChangeLog-2006 ChangeLog-3.x MAINTAINERS Makefile.in NEWS PROBLEMS README abug-rom.c acinclude.m4 aclocal.m4 ada-exp.y ada-lang.c ada-lang.h ada-lex.l ada-typeprint.c ada-valprint.c aix-thread.c alpha-linux-nat.c alpha-linux-tdep.c alpha-mdebug-tdep.c alpha-nat.c alpha-osf1-tdep.c alpha-tdep.c alpha-tdep.h alphabsd-nat.c alphabsd-tdep.c alphabsd-tdep.h alphafbsd-tdep.c alphanbsd-tdep.c alphaobsd-tdep.c amd64-linux-nat.c amd64-linux-tdep.c amd64-linux-tdep.h amd64-nat.c amd64-nat.h amd64-sol2-tdep.c amd64-tdep.c amd64-tdep.h amd64bsd-nat.c amd64fbsd-nat.c amd64fbsd-tdep.c amd64nbsd-nat.c amd64nbsd-tdep.c amd64obsd-nat.c amd64obsd-tdep.c annotate.c annotate.h arch-utils.c arch-utils.h arm-linux-nat.c arm-linux-tdep.c arm-linux-tdep.h arm-tdep.c arm-tdep.h armbsd-tdep.c armnbsd-nat.c armnbsd-tdep.c armobsd-tdep.c auxv.c auxv.h avr-tdep.c ax-gdb.c ax-gdb.h ax-general.c ax.h bcache.c bcache.h bfd-target.c bfd-target.h block.c block.h blockframe.c breakpoint.c breakpoint.h bsd-kvm.c bsd-kvm.h bsd-uthread.c bsd-uthread.h buildsym.c buildsym.h c-exp.y c-lang.c c-lang.h c-typeprint.c c-valprint.c call-cmds.h charset.c charset.h cli-out.c cli-out.h coff-pe-read.c coff-pe-read.h coff-solib.c coff-solib.h