Hrvoje Niksic wrote: [snip] Try the following instead. #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <sigcontext.h> void segv_handler(int sig, struct sigcontext ctx) { printf ("Fault address: %p\n", ctx.cr2); exit (0); } int main (void) { struct sigaction act; sigaction (SIGSEGV, NULL, &act); act.sa_handler = segv_handler; sigemptyset (&act.sa_mask); act.sa_flags = 0; sigaction (SIGSEGV, &act, NULL); *(char *)0xdeadbeef = 'x'; return 0; /* unreached */ } Clearly it isn't portable (the sigcontext structure is processor-specific), but then I'm not sure that there is any portable method. Stevens[1] indicates that SA_SIGINFO and struct siginfo are specific to SVR4, and that BSD 4.3+ signal handlers have the prototype: handler(int signo, int code, struct sigcontext *scp) -- Glynn Clements <glynn(a)sensei.co.uk&gt; [1] Advanced Programming in the Unix Environment W Richard Stevens Addison Wesley