未释放互斥锁线程退出

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

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void *f(void *args)
{
        pthread_mutex_lock(&mutex);
        printf("lock in f without unlock!\n");
        return NULL;
}

int main()
{
        pthread_t tid;
        pthread_create(&tid, NULL, f, NULL);
        sleep(1);
        pthread_mutex_lock(&mutex);
        printf("lock in main\n");
        pthread_mutex_unlock(&mutex);
        return 0;
}

如上所示程序，线程退出前未释放锁，执行后程序结果为：

说明线程的退出不会导致锁的释放！！！