使用互斥量實現多線程交替打印helloworld

/*===============================================================
*  Copyright(C) 2020 Burgess Fan aLL rights reserved.
*  
*  文件名稱：mutex.c
*   創 建 者：Burgess
*   建立日期：2020年05月10日
================================================================*/
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <stdlib.h>

pthread_mutex_t mutex=PTHREAD_MUTEX_INITIALIZER;
int sum=0;

void* thr1(void *arg)
{
    while(1)
    {
        pthread_mutex_lock(&mutex);//加鎖
        printf("I am thread No1,hello world!\n");
        sleep(1);
        pthread_mutex_unlock(&mutex);//釋放鎖
        sleep(1);//增長睡眠時間確保不會讓線程自己搶到鎖
    }
}

void* thr2(void *arg)
{
    while(1)
    {
        pthread_mutex_lock(&mutex);
        printf("I am thread No2,HELLO  WORLD!\n");
        sleep(1);
        pthread_mutex_unlock(&mutex);
        sleep(1);
    }
}

int main()
{
    pthread_t tid[2];
    pthread_create(&tid[0],NULL,thr1,NULL);
    pthread_create(&tid[1],NULL,thr2,NULL);
    pthread_join(tid[0],NULL);
    pthread_join(tid[1],NULL);
    return 0;
}