#include <signal.h>
#include <stdio.h>
#include <string.h>
static volatile int event = 0;

static void handleSignal() {
    event = 1;
}

int main(int argc, char *argv[])
{
    puts("bar");
    sigset_t mask;
    sigset_t old;
    signal(SIGUSR1, handleSignal);
    sigaddset(&mask, SIGUSR1);
    sigprocmask(SIG_BLOCK, &mask, &old);
    while (event == 0) {
        sigsuspend(&old);
    }

    event = 0;
    sigprocmask(SIG_SETMASK, &old,NULL);
    puts("foo");
    return 0;
}