1 #include 
     
       2 #include 
      
        3 #include 
       
         4  5 #define UPBOUND 100 6  7 sem_t sem1; 8 sem_t sem2; 9 10 //int i=0;11 12 void *threadfunc1(void *p)13 {14     int i=0;15     while(i<100)16     {17         sem_wait(&sem1);18         i++;19         printf("111 thread i is %d\n",i);20         sem_post(&sem2);21     }22     return NULL;23 }24 25 26 void *threadfunc2(void *p)27 {28     int i=0;29     while(i<100)30     {31         sem_wait(&sem2);32         i++;33         printf("222 thread i is %d\n",i);34         sem_post(&sem1);35     }36     return NULL;37 }38 39 int main()40 {41    sem_init(&sem1, 0, 1);            //线程间共享，初值为142    sem_init(&sem2, 0, 0);43 44    pthread_t tid1=0, tid2=0;45 46    pthread_create(&tid1,NULL,&threadfunc1,NULL);47    pthread_create(&tid2,NULL,&threadfunc2,NULL);48 49    pthread_join(tid1,NULL);50    pthread_join(tid2,NULL);51 52    sem_destroy(&sem1);53    sem_destroy(&sem2);54    55    return 0;56 }