生产者消费者问题是多线程并发中一个非常经典的问题。我在这里实现了一个基于C++11的，单生产者单消费者的版本，供大家参考。
#include <windows.h>
#include <iostream>
#include <cstdlib>
#include <mutex>
#include <thread>
#include <condition_variable>
const int bufferSize=;
struct ItemRepository
{
int item_buffer[bufferSize];
int write_pos; //current position of producer
int read_pos; //current position of consumer
std::condition_variable not_empty_con;
std::condition_variable not_full_con;
std::mutex mtx;
}itemRepository; void produce_one_item(ItemRepository*ir)
{
if (!ir)
return;
int* item_buffer = ir->item_buffer;
std::unique_lock<std::mutex> lock(ir->mtx);
if (ir->write_pos == ir->read_pos&&
item_buffer[ir->write_pos] == )//the repository is full
{
std::cout << "The producer is waiting for an empty." << std::endl;
ir->not_full_con.wait(lock);
} item_buffer[ir->write_pos] = ;//now the buffer in this position is full
std::cout << "The producer produces a new item on " << ir->write_pos << std::endl;
ir->write_pos++;
ir->not_empty_con.notify_all();//notify the consumer to consume items if (ir->write_pos == bufferSize)
ir->write_pos = ;
} void consume_one_item(ItemRepository*ir)
{
if (!ir)
return;
int* item_buffer = ir->item_buffer;
std::unique_lock<std::mutex> lock(ir->mtx); if (ir->read_pos == ir->write_pos&&
item_buffer[ir->write_pos] == )//the repository is empty
{
std::cout << "The consumer is waiting for items." << std::endl;
ir->not_empty_con.wait(lock);
} item_buffer[ir->read_pos] = ;//now the buffer in this position is empty
std::cout << "The consumer consumes an item on " << ir->read_pos << std::endl;
ir->read_pos++;
ir->not_full_con.notify_all();//notify the producer to produce new items if (ir->read_pos == bufferSize)
ir->read_pos = ;
} void produceTask()
{
for (int i = ; i < ; i++)
produce_one_item(&itemRepository);
} void consumeTask()
{
for (int i = ; i < ; i++)
{
Sleep();
consume_one_item(&itemRepository);
}
} void initializeRepository(ItemRepository*ir)
{
if (!ir)
return;
ir->read_pos = ;
ir->write_pos = ;
} int main()
{
initializeRepository(&itemRepository);
std::thread producer(produceTask);
std::thread consumer(consumeTask);
producer.join();
consumer.join();
system("pause");
return ;
}
注意我判断item_buffer中的物品是否全空或者全满的条件：生产者和消费者的位置相等时，若该位置上为空则buffer全空，若为满则buffer全满。