Unix Custom Signal Handler

eino (Eino) — Thu, 05 Oct 2006 16:13:38 GMT

This code allows one to catch a environment signal.
When the said signal is received (11 - SIGSEGV in this case), the signal handling function is called.

I used it to catch a SIGSEGV in a program, which occured regularly, but never when I used GDB.
In the sig_handler I put an infinite loop, and when the program was there I was able to attach
GDB to the program and backtrace to the function where the error occured



#include 

#include 



void sig_handler(int signum)

{

        printf("Catched signal %d", signum);

        exit(0);

}



int main()

{

        int *ptr;

        struct sigaction new_action, old_action;



        // set up new handler to specify new action

        new_action.sa_handler = sig_handler;

        //sigemptyset (&new_action.sa_mask);

        new_action.sa_flags = 0;

        // attach SIGSEV to sig_handler

        sigaction(11, &new_action, NULL);





        printf("in loop\n");

        sleep(2);



        ptr = (int *)9;

        printf("%d\n", *ptr); // this should raise a SIGSEV

}

DZone Snippets: signals code

Unix Custom Signal Handler