#include <pthread.h>
#include <stdio.h>
#include <semaphore.h>

int global_shared;
sem_t thread1_done;

static void *
thread1(void * _tn)
{
    global_shared++;
    sem_post(&thread1_done);
    return NULL;
}

static void *
thread2(void * _tn)
{
    sem_wait(&thread1_done);
    global_shared++;
    return NULL;
}

int
main()
{
    int N = 2;
    pthread_t t[N];
    sem_init(&thread1_done, 0, 0);
    pthread_create(t + 0, NULL, thread1, NULL);
    pthread_create(t + 1, NULL, thread2, NULL);

    pthread_join(t[0], NULL);
    pthread_join(t[1], NULL);
    printf("global_shared = %d\n", global_shared);
    return 0;
}