linux mutex

#include <iostream>
#include <queue>
#include <cstdlib>

#include <unistd.h>
#include <pthread.h>

using namespace std;

pthread_mutex_t mutex;
queue<int> product;

void* produce(void* ptr)
{
    for(int i = ; i < ; ++i)
    {
        pthread_mutex_lock(&mutex);
        product.push(i);
        pthread_mutex_unlock(&mutex);
    }
}

void* consume(void* ptr)
{
    for(int i = ; i < ;)
    {
        pthread_mutex_lock(&mutex);
        if(product.empty())
        {
            pthread_mutex_unlock(&mutex);
            continue;
        }
        ++i;
        cout << "consume" << product.front() << endl;
        product.pop();
        pthread_mutex_unlock(&mutex);
    }
}

int main()
{
    pthread_mutex_init(&mutex, NULL);
    pthread_t tid1, tid2;

    pthread_create(&tid1, NULL, consume, NULL);
    pthread_create(&tid2, NULL, produce, NULL);

    void* retVal;

    pthread_join(tid1, &retVal);
    pthread_join(tid2, &retVal);
    return ;
}

这种效率不高，因为消费者需要不停的去询问队列中是否不为空。