CODEWITHSUNDEEP
clinuxsignalsposixsigaction
Yves
Yves

Reputation: 12431

Why does sigaction invoke core dump

int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);
If act is non-NULL, the new action for signal signum is installed from act. If oldact is non-NULL, the previous action is saved in oldact.

This comes from https://linux.die.net/man/2/sigaction, I don't quite understand what "previous action" means. Does it means the action by default referred to the signum? I've tested the code as below but it gave me a core dumped:

#include <signal.h>
#include <unistd.h>    

struct sigaction act, oact;
void func(int p)
{
    oact.sa_handler(p);  # core dumped here
}

int main(int argc, char **argv)
{
    act.sa_handler = func;
    sigaction(SIGINT, &act, &oact);
    sleep(100);
    return 0;
}

Upvotes: 1

Views: 195

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