Kodexempel F12

/* signal.h, stdio.h, unistd.h */

int sigintflag = 0;

void handler(int signo)
{
  sigintflag = 1;
}

int main(void)
{
  if (signal(SIGINT, handler) == SIG_ERR) ...
  while (1) {
    sleep(1);
    if (sigintflag) {
      puts("Bye bye!");
      return 0;
    }
  }
}



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

void handler(int signo)
{
  write(STDERR_FILENO,"Please be patient...", 20);
}

int main(void)
{
  ...

  signal(SIGINT, handler);
  /* Important processing here */
  
  signal(SIGINT, SIG_DFL);
  /* Less important code here */
}



/* signal.h, stdio.h, unistd.h */

void sighand(int signo)
{
  write(STDOUT_FILENO, "Handled SIGINT\n", 14);
}

int main(void)
{
  sigset_t newmask, oldmask, pendmask;

  signal(SIGINT, sighand);
  sigemptyset(&newmask);
  sigaddset(&newmask, SIGINT);
  sigprocmask(SIG_BLOCK, &newmask, &oldmask);
  sleep(5);
  sigpending(&pendmask);
  if (sigismember(&pendmask, SIGINT)) puts("\nSIGINT pending");
  sigprocmask(SIG_SETMASK, &oldmask, NULL);
  puts("\nSIGINT unblocked");
  sleep(5);
  return 0;
}