生产者消费者使用PTHreads和Semaphore的同步错误

我已经使用pthreads和semaphores编写了一个简单的生产者消费者。有时我会失去订单（在生产者生产之前消费者消费）输出。请帮助我找到问题。我已经使用各种来源和教程验证了逻辑，但仍会获得不希望的结果。

    #include <iostream>
    #include <pthread.h>
    #include <semaphore.h>
    #include <string>
    #include <sstream>
    #include <unistd.h>
    #include "pthread_barrier.hpp"
    sem_t empty;
    sem_t full;
    sem_t lock;
    pthread_mutex_t wlock;
    pthread_barrier_t pbarrier;
    pthread_barrier_t cbarrier;
    pthread_attr_t tattr;
    #define BUFF_SIZE 100
    volatile bool buffer[BUFF_SIZE];
    int prodIterator = 0;
    int consIterator = 0;
    void *Producer(void *args)
    {   
        pthread_barrier_wait(&pbarrier);
        while(1) {
            sem_wait(&empty);
            sem_wait(&lock);
            buffer[prodIterator] = true;
            pthread_mutex_lock(&wlock);
            std::stringstream str;
            std::cout<<"producer produced = "<<prodIterator<<"n";
            pthread_mutex_unlock(&wlock);
            prodIterator = (++prodIterator)% BUFF_SIZE;
            sem_post(&lock);
            sem_post(&full);
            sleep(1);
        }
    }
    void *Consumer(void *args)
    {
        pthread_barrier_wait(&cbarrier);
        while(1) {
            sem_wait(&full);
            sem_wait(&lock);
            buffer[consIterator] = false;
            pthread_mutex_lock(&wlock);
            std::cout<<"Consumer consumed = "<<consIterator<<"n";
            pthread_mutex_unlock(&wlock);
            consIterator = (++consIterator)% BUFF_SIZE;
            sem_post(&lock);
            sem_post(&empty);
            sleep(1);
        }   
    }

    int main()
    {
        sem_init(&empty, 0, BUFF_SIZE);
        sem_init(&full, 0, 0);
        sem_init(&lock, 0, 1);
        pthread_mutex_init(&wlock, NULL);
        pthread_t prod[10];
        pthread_t cons[10];
        unsigned pcount = 5;
        unsigned ccount = 2;
        pthread_barrier_init(&pbarrier, NULL, pcount);
        pthread_barrier_init(&cbarrier, NULL, ccount);
        pthread_attr_init(&tattr);
        pthread_attr_setdetachstate(&tattr, PTHREAD_CREATE_DETACHED);
        for(int i=0;i<5;i++) {
            pthread_create(&prod[i], &tattr, Producer, NULL);
        }
        for(int i=0;i<2;i++) {
            pthread_create(&cons[i], &tattr, Consumer, NULL);
        }
        pthread_exit(NULL);
    }