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

static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cv = PTHREAD_COND_INITIALIZER;
static int finished = 0;

static void *child_thread(void *arg) { (void)arg;
    (void)arg;
    printf("child running\n");
    pthread_mutex_lock(&mtx);
    finished = 1;
    pthread_cond_signal(&cv);
    pthread_mutex_unlock(&mtx);
    return NULL;
}

int main(void) {
    printf("parent starting\n");
    pthread_t tid;
    pthread_create(&tid, NULL, child_thread, NULL);
    pthread_mutex_lock(&mtx);
    while (finished == 0) {
        pthread_cond_wait(&cv, &mtx);
    }
    pthread_mutex_unlock(&mtx);
    printf("parent finishing\n");
    pthread_join(tid, NULL);
    return 0;
}