prodcom.c

linux下多线程实现生产者消费者及用并行算法求圆周率等经典算法

#include <pthread.h>
#include <stdio.h>
#include <semaphore.h>

sem_t empty, full;       // the global semaphores
int data;                // shared buffer
int num;

// deposit 1, ..., num into the data buffer
void *Producer(void *arg) 
{
     int produced;
     printf("Producer created\n");
     for (produced = 1; produced <= num; produced++) {
	  sem_wait(&empty);
	  data = produced;
	  sem_post(&full);
     }
}
// fetch num items from the buffer and sum them
void *Consumer(void *arg) 
{
     int total = 0, consumed;
     printf("Consumer created\n");
     for (consumed = 0; consumed < num; consumed++) {
	  sem_wait(&full);
	  total = total+data;
	  sem_post(&empty);
     }
     printf("for %d iterations, the total is %d\n", num, total);
}
int main(int argc, char *argv[]) 
{

     pthread_t pid, cid;  

     num = atoi(argv[1]);
     sem_init(&empty, 0, 1);  // sem empty = 1
     sem_init(&full, 0, 0);   // sem full = 0 

     printf("main started\n");
     pthread_create(&pid, NULL, Producer, NULL);
     pthread_create(&cid, NULL, Consumer, NULL);
     pthread_join(pid, NULL);
     pthread_join(cid, NULL);
     printf("main done\n");
}