生产者消费者简单实现

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

#define BUFFER_SIZE 16

struct prodcons{
    int buffer[BUFFER_SIZE];
    pthread_mutex_t lock;
    int readpos, writepos;
    pthread_cond_t notempty;
    pthread_cond_t notfull;
};

void init(struct prodcons *b)
{
    pthread_mutex_init(&b->lock, NULL);
    pthread_cond_init(&b->notempty, NULL);
    pthread_cond_init(&b->notfull, NULL);
    b->readpos = 0;
    b->writepos = 0;
}

void put(struct prodcons *b, int data)
{
    pthread_mutex_lock(&b->lock);
    if ((b->writepos + 1) % BUFFER_SIZE == b->readpos){
        pthread_cond_wait(&b->notfull, &b->lock);
    }

    b->buffer[b->writepos] = data;
    b->writepos++;
    if (b->writepos >= BUFFER_SIZE)
        b->writepos = 0;

    pthread_cond_signal(&b->notempty);
    pthread_mutex_unlock(&b->lock);

}

int get(struct prodcons *b)
{
    int data;
    pthread_mutex_lock(&b->lock);

    if (b->writepos == b->readpos){
        pthread_cond_wait(&b->notempty, &b->lock);
    }

    data = b->buffer[b->readpos];
    b->readpos++;
    if (b->readpos >= BUFFER_SIZE)
        b->readpos = 0;

    pthread_cond_signal(&b->notfull);
    pthread_mutex_unlock(&b->lock);

    return data;
}

#define OVER (-1)
struct prodcons buffer;
void *producer(void *data)
{
    int n;
    for (n = 0; n < 10000; n++){
        printf("%d--->\n", n);
        put(&buffer, n);
    }

    put(&buffer, OVER);
    return NULL;
}

void *consumer(void *data)
{
    int d;
    while (1){
        d = get(&buffer);
        if (d == OVER)
            break;
        printf("--->%d\n", d);
    }

    return NULL;
}

int main(void)
{
    pthread_t th_a, th_b;
    void *retval;

    init(&buffer);

    pthread_create(&th_a, NULL, producer, 0);
    pthread_create(&th_b, NULL, consumer, 0);

    pthread_join(th_a, &retval);
    pthread_join(th_b, &retval);

    return 0;
}