mutex互斥锁

#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
#include<errno.h>
#include<unistd.h>
#include<string.h>

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;//初始化了一个MUTEX锁

void *func1(void *arg)
{
     pthread_mutex_lock(&mutex);//给mutex加锁,这是一条原子操作，不可能出现两个线程同时执行这个代码
     int *a = (int *) arg;
     printf("thread%d start\n", *a);
     int i;
     for (i = 0; i < 10; i++)
     {
          printf("thread%d is running\n", *a);
          sleep(1);
     }
     printf("thread%d end\n", *a);
     pthread_mutex_unlock(&mutex);//给mutex解锁
     pthread_exit(NULL);
}

int main(int arg, char * args[])
{
     printf("process start\n");
     pthread_t thr_d1, thr_d2;
     int i[2];
     i[0] = 1;
     i[1] = 2;
     pthread_create(&thr_d1, NULL, func1, &i[0]);
     pthread_create(&thr_d2, NULL, func1, &i[1]);
     pthread_join(thr_d1, NULL);
     pthread_join(thr_d2, NULL);
     printf("process end\n");
     return 0;
}