线程同步(互斥量)

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
pthread_mutex_t mutex;
int x;

void thread1(void)
{
    while(x>0)
    {
        pthread_mutex_lock(&mutex);
        printf("thread 1 is running x=%dn",x);
        x--;
        pthread_mutex_unlock(&mutex);
        sleep(1);
    }
    pthread_exit(NULL);
}

void thread2(void)
{
    while(x>0)
    {
        pthread_mutex_lock(&mutex);
        printf("thread 2 is running x=%dn",x);
        x--;
        pthread_mutex_unlock(&mutex);
        sleep(1);
    }
    pthread_exit(NULL);
}

int main()
{
    pthread_t id1,id2;
    int ret;
    ret = pthread_mutex_init(&mutex,NULL);
    if(ret!=0)
    {
        printf("pthread_mutex_init failedn");
        exit(1);
    }
    x=10;
    
    ret = pthread_create(&id1,NULL,(void *)&thread1,NULL);
    if(ret!=0)
    {
        printf("pthread_create 1 failedn");
        exit(1);
    }
    
    ret = pthread_create(&id2,NULL,(void *)&thread2,NULL);
    if(ret!=0)
    {
        printf("pthread_create 2 failedn");
        exit(1);
    }
    
    pthread_join(id1,NULL);
    pthread_join(id2,NULL);
    return 0;
}