#include <stdatomic.h>
#include <stdio.h>
#include <threads.h>

atomic_int x; // _Atomic int

int thread1(void *arg) {
    (void)arg;

    printf("Thread 1: Sleeping for 1.5 seconds\n");
    thrd_sleep(&(struct timespec){.tv_sec = 1, .tv_nsec = 500000000}, NULL);

    printf("Thread 1: Setting x to 3490\n");
    x = 3490;

    printf("Thread 1: Exiting\n");
    return 0;
}

int thread2(void *arg) {
    (void)arg;

    printf("Thread 2: Waiting for 3490\n");
    while (x != 3490); // spin here

    printf("Thread 2: Got 3490--exiting!\n");
    return 0;
}

int main(void) {
    x = 0;

    thrd_t t1, t2;

    thrd_create(&t1, thread1, NULL);
    thrd_create(&t2, thread2, NULL);

    thrd_join(t1, NULL);
    thrd_join(t2, NULL);

    printf("Main    : Threads are done, so x better be 3490\n");
    printf("Main    : And indeed, x == %d\n", x);
}