#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
pthread_mutex_t mutex;
 pthread_cond_t  cond;
 void * child1(void *arg)
 {        
   pthread_cleanup_push(pthread_mutex_unlock,&mutex);  /* comment 1 */  
   while(1){               
 		printf("thread 1 get running \n");       
 printf("thread 1 pthread_mutex_lock returns %d\n",pthread_mutex_lock(&mutex)); 
           pthread_cond_wait(&cond,&mutex);                    
           printf("thread 1 condition applied\n");        
          pthread_mutex_unlock(&mutex);                   
          sleep(5);   
         }      
  pthread_cleanup_pop(0);     /* comment 2 */}
  void *child2(void *arg)
   {       
      while(1){              
  	       sleep(3);               /* comment 3 */            
           printf("thread 2 get running.\n");       
           printf("thread 2 pthread_mutex_lock returns %d\n",pthread_mutex_lock(&mutex));        
            pthread_cond_wait(&cond,&mutex);   
            printf("thread 2 condition applied\n");  
            pthread_mutex_unlock(&mutex);   
            sleep(1);     
            }
    }

 int main(void)
 {    
    int tid1,tid2;     
    printf("hello, condition variable test\n");        
    pthread_mutex_init(&mutex,NULL);   
    pthread_cond_init(&cond,NULL);     
    pthread_create(&tid1,NULL,child1,NULL);    
    pthread_create(&tid2,NULL,child2,NULL);  
  do{      
       sleep(2);                   /* comment 4 */     
      pthread_cancel(tid1);       /* comment 5 */          
        sleep(2);                   /* comment 6 */   
     pthread_cond_signal(&cond);   
       }while(1);      
  
   sleep(100);    
   pthread_exit(0);
 }