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/*
* Expected output of ./sig-nodefer:
* SIGUSR2: blocked
* SIGTERM: blocked
*/
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
void handler(int signum)
{
sigset_t mask;
sigprocmask(SIG_BLOCK, NULL, &mask);
printf("SIGUSR2: %s\n",
sigismember(&mask, SIGUSR2) ? "blocked" : "not blocked");
printf("SIGTERM: %s\n",
sigismember(&mask, SIGTERM) ? "blocked" : "not blocked");
}
int main(int argc, char **argv)
{
pid_t pid;
pid = fork();
if (pid == -1) {
perror("fork");
exit(EXIT_FAILURE);
} else if (!pid) {
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = handler;
act.sa_flags = SA_NODEFER;
sigaddset(&act.sa_mask, SIGUSR2);
sigaddset(&act.sa_mask, SIGTERM);
sigaction(SIGUSR1, &act, NULL);
pause();
} else {
int status;
sleep(3);
kill(pid, SIGUSR1);
waitpid(pid, &status, 0);
}
return 0;
}
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