线程条件变量

范例如下：

#include<stdio.h>

#include<unistd.h>
#include<pthread.h>
pthread_mutex_t mutex;
pthread_cond_t cond;
void * thread1(void *arg){
   pthread_cleanup_push(pthread_mutex_unlock,&mutex);
   while(1)
   {
      printf("thread1 is running\n");
      pthread_mutex_lock(&mutex);
      pthread_cond_wait(&cond,&mutex);
      printf("thread1 applied the condition\n");
      pthread_mutex_unlock(&mutex);
      sleep(4);
   }
   pthread_cleanup_pop(0);
}


void *thread2(void *arg)
{
   while(1){
     printf("thread2 is running\n");
     pthread_mutex_lock(&mutex);
     pthread_cond_wait(&cond,&mutex);
     printf("thread2 applied the condition\n");

     pthread_mutex_unlock(&mutex);

     sleep(1);


   }
}
int main(void){
   pthread_t tid1,tid2;
   printf("condition variable study!\n");
   pthread_mutex_init(&mutex,NULL);
   pthread_cond_init(&cond,NULL);
   pthread_create(&tid1,NULL,(void*)thread1,NULL);
   pthread_create(&tid2,NULL,(void*)thread2,NULL);
   do{
      pthread_cond_signal(&cond);
   }while(1);
   sleep(50);
   pthread_exit(0);




}