int main (void) {
int error;
int i;
pthread_t tid[NUMTHREADS];
int val;
if (initshared(0)) {
perror("Could not initialize shared variable");
return 1;
}
getshared(&val);
printf("Shared variable initialized to %d\n", val);
for (i = 0; i < NUMTHREADS; i++)
if (error = pthread_create(tid+i, NULL, increment, NULL))
fprintf(stderr, "Failed to create thread: %s\n", strerror(error));
printf("Number of threads created: %d\n", NUMTHREADS);
for (i = 0; i < NUMTHREADS; i++)
if (error = pthread_join(tid[i], NULL))
fprintf(stderr, "Failed to join thread: %s\n", strerror(error));
printf("All threads done\n");
getshared(&val);
printf("Shared variable now has value %d\n", val);
return 0;
}
int main(int argc, char *argv[]) {
struct sigaction act;
int key;
sigset_t mask, oldmask;
if (argc != 2) {
fprintf(stderr, "Usage: %s key\n", argv[0]);
return 1;
}
key = atoi(argv[1]);
if (initshared(key) == -1) {
perror("Failed to initialize shared memory");
return 1;
}
if ((sigfillset(&mask) == -1) ||
(sigprocmask(SIG_SETMASK, &mask, &oldmask) == -1)) {
perror("Failed to block signals to set up handlers");
return 1;
}
printf("This is process %ld waiting for SIGUSR1 (%d)\n",
(long)getpid(), SIGUSR1);
act.sa_handler = showit;
act.sa_flags = 0;
if ((sigemptyset(&act.sa_mask) == -1) ||
(sigaction(SIGUSR1, &act, NULL) == -1)) {
perror("Failed to set up signal handler");
return 1;
}
if (sigprocmask(SIG_SETMASK, &oldmask, NULL) == -1) {
perror("Failed to unblock signals");
return 1;
}
for ( ; ; )
pause();
}
