POSIX多线程不常见死锁案例

pthread_barrier_t barrier = NULL;
pthread_mutex_t mx = PTHREAD_MUTEX_INITIALIZER;
static int serialThreadCount = 0;

void* func(void* arg)
{
    assert(pthread_mutex_lock(&mx) == 0);
    int result = pthread_barrier_wait(&barrier);

    if (PTHREAD_BARRIER_SERIAL_THREAD == result) {
        serialThreadCount++;
    }

    assert(pthread_mutex_unlock(&mx) == 0);
    return arg;
}

int main()
{
    pthread_t t1, t2;
    void* ret;

    serialThreadCount = 0;
    assert(pthread_barrier_init(&barrier, NULL, 2) == 0);
    assert(pthread_create(&t1, NULL, func, (void*)1) == 0);
    assert(pthread_create(&t2, NULL, func, (void*)2) == 0);
    printf("t1 and t2 created...\n");

    assert(pthread_join(t1, &ret) == 0);
    printf("t1 joined, retval %d\n", ret);
    assert(pthread_join(t2, &ret) == 0);
    printf("t2 joined, retval %d\n", ret);

    assert(serialThreadCount == 1);

    assert(pthread_barrier_destroy(&barrier) == 0);
    assert(pthread_mutex_destroy(&mx) == 0);
        
    return 0;
}