线程互斥锁实验 - 曲径通幽论坛

#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include <string.h>

void *thread_function (void *arg);
pthread_mutex_t work_mutex;     //全局互斥锁对象

#define WORK_SIZE 1024
char work_area[WORK_SIZE];
int time_to_exit = 0;

int main (int argc, char *argv[])
{
        int res;
        pthread_t a_thread;
        void *thread_result;

        res = pthread_mutex_init (&work_mutex, NULL);   //初始化互斥锁
        if (res != 0) {
                printf ("Mutex initialization failed");
                exit (EXIT_FAILURE);
        }
        res = pthread_create (&a_thread, NULL, thread_function, NULL);
        if (res != 0) {
                printf ("Thread creation failed");
                exit (EXIT_FAILURE);
        }
        pthread_mutex_lock (&work_mutex);
        printf ("等待全部变量 time_to_exit 的变为 1\n");

        while (!time_to_exit) {
                printf ("还没改变,继续等待 3s ...\n");
                sleep(3);
        }

        pthread_mutex_unlock (&work_mutex);
        pthread_mutex_destroy (&work_mutex);
        pthread_join (a_thread, &thread_result);

        return (0);
}

void *thread_function (void *arg)
{
        sleep(1);
        pthread_mutex_lock (&work_mutex);
        printf ("资源没有释放,无法打印此行信息\n");
        time_to_exit = 1;
}