生产者消费者的例子-使用条件变量

#include <stdio.h> 
#include <stdlib.h> 
#include <time.h> 
#include <pthread.h>

pthread_mutex_t x;
pthread_cond_t cv;
static int s=0;

int rand_num[100]={0};
int  rd=0,wt=0;

void* threadConsumer(void* param)
{
   int r;
   int tid=*(int*)param;
   while(1)
   { 
        pthread_mutex_lock(&x);
        while(s<=0)
        { 
            printf("%u waiiting...\n",tid);
            pthread_cond_wait(&cv,&x);
        }
        r = rd;
        printf("%u get number %d %d\n",tid,r,rand_num[r]);
        rand_num[r]=0;
        rd=++rd%100;
        
        s--;
            
        pthread_mutex_unlock(&x);
        usleep(0);
    }

}

void* threadProduct(void* param)
{
    int i=0;
    rd=wt=0;
    
    while(1)
    {
        unsigned int seed = time(NULL);
        int left=0,left2;
        pthread_mutex_lock(&x);

        left=(wt>=rd)?(100-wt+rd):(rd-wt);
        if(left==0||s==100)
        {
          pthread_mutex_unlock(&x);
          usleep(0);
          continue;
        }

        left2=left;
        
        while(left>0)
        { 
            rand_num[wt]=rand_r(&seed);
            wt=++wt%100;
            s++;
            left--;
        }
        pthread_mutex_unlock(&x);
        
        pthread_cond_broadcast(&cv);
                printf("new add %d\n",left2);
                usleep(0);
    }
}

int main(int arc ,char** argv)
{
    int i=0;
    pthread_t tids[101]={0};
    pthread_attr_t attr;

    pthread_attr_init(&attr);
    
    for(i=0;i<50;i++)
    {
        pthread_create(&tids[i],&attr,threadConsumer,(void*)(tids+i));
    }

    pthread_create(&tids[i],&attr,threadProduct,(void*)(tids+100));
    
    pthread_join(tids[i],NULL);
    
    return 0;
    
}