C++11实现生产者消费者

/************************************
生产者消费者，多线程实现问题
有一个存储的队列
  生产者生产
  消费者取消费
1：注意：结构体作为参数，&是引用传递 *是地址传递
2：互斥锁的实现和条件变量
************************************/
#include <thread>
#include <mutex>
#include <condition_variable>
#include <unistd.h>
#include <iostream>
using namespace std;
//使用循环队列来进行存储消息
typedef struct buffer
{
  int buff[10];
  size_t read_position;
  size_t write_position;
  //采用互斥锁的方式实现生产和消费的异步取
  mutex mtx;
  condition_variable not_full; //可写信号
  condition_variable not_empty; //可读信号
  buffer()
  {
    read_position = 0;
    write_position = 0;
  };
}ring_buffer;
ring_buffer save_buffer;
void produce_item(ring_buffer *buffer, int i)
{
  //把i放入buffer中 要加锁
  unique_lock<mutex> lock(buffer->mtx);
  //根据标志，来等待或者存
  while((buffer->write_position+1)%10 == buffer->read_position)
  {
    cout<<"buffer is full now, producer is waiting \n"<<endl;
    (buffer->not_full).wait(lock);//等待释放锁的信号
  }
  //生产者加入数据
  (buffer->buff)[buffer->write_position] = i;
  buffer->write_position++;
  if(buffer->write_position == 10)
    buffer->write_position = 0;
  //给消费者发信号
  (buffer->not_empty).notify_all();
  lock.unlock();
}
int consumer_item(ring_buffer *buffer)
{
  //从buffer中取值返回 要加锁
  int data;
  unique_lock<mutex> lock(buffer->mtx);
  while(buffer->read_position == buffer->write_position)
  {
    cout<<"buffer is empty, consumer is waiting";
    (buffer->not_empty).wait(lock);
  }
  data = (buffer->buff)[buffer->read_position];
  buffer->read_position ++;
  if(buffer->read_position >= 10)
  {
    buffer->read_position = 0;
  }
  (buffer->not_full).notify_all();
  lock.unlock();
  return data;
}
//负责生产消息，放入队列中//根据写标志位写在对应位上
void producer()
{
  for(int i=0; i<100; i++)
  {
    produce_item(&save_buffer, i);
  }
}
void consumer()
{
  static int cnt = 0;
  while(1)
  {
    sleep(1);
    int item = consumer_item(&save_buffer);
    cout<<"consumer item is:"<<item<<endl;
    if(++cnt == 100)
    {
      break;
    }
  }
}
int main()
{
  thread produce(producer);
  thread consumes(consumer);
  produce.join();
  consumes.join();
  getchar();
  return 0;
}