ptg10805159460 Thread Control Chapter 12
int err;
printf("parent unlocking locks...\n");
if ((err = pthread_mutex_unlock(&lock1)) != 0)
err_cont(err, "can’t unlock lock1 in parent handler");
if ((err = pthread_mutex_unlock(&lock2)) != 0)
err_cont(err, "can’t unlock lock2 in parent handler");
}
void
child(void)
{
int err;
printf("child unlocking locks...\n");
if ((err = pthread_mutex_unlock(&lock1)) != 0)
err_cont(err, "can’t unlock lock1 in child handler");
if ((err = pthread_mutex_unlock(&lock2)) != 0)
err_cont(err, "can’t unlock lock2 in child handler");
}
void *
thr_fn(void *arg)
{
printf("thread started...\n");
pause();
return(0);
}
int
main(void)
{
int err;
pid_t pid;
pthread_t tid;
if ((err = pthread_atfork(prepare, parent, child)) != 0)
err_exit(err, "can’t install fork handlers");
if ((err = pthread_create(&tid, NULL, thr_fn, 0)) != 0)
err_exit(err, "can’t create thread");
sleep(2);
printf("parent about to fork...\n");
if ((pid = fork()) < 0)
err_quit("fork failed");
else if (pid == 0) /* child */
printf("child returned from fork\n");
else /* parent */
printf("parent returned from fork\n");
exit(0);
}Figure 12.17 pthread_atforkexample