c++11 condition_variable test

cv_test.cpp

#include <iostream>
#include <chrono>
#include <thread>
#include <mutex>
#include <condition_variable>

/// compile : g++ -std=c++11 -pthread cv_test.cpp -o cv_test && ./cv_test

std::condition_variable _cv;
std::mutex _mutex;
int32_t _value;
int32_t _running;

void provider()
{
    _running = true;

    while (_running) {
        {
            std::lock_guard<std::mutex> lock(_mutex);
            _value++;
        }
        _cv.notify_one();
        printf("%s %4d %s : notify value:%d\n", __FILE__, __LINE__, __func__, _value);
        std::this_thread::sleep_for(std::chrono::milliseconds(100));
    }
    printf("%s %4d %s : out\n", __FILE__, __LINE__, __func__);
}

void consumer()
{
    _running = true;
    while (_running) {
        std::unique_lock<std::mutex> lock(_mutex);
        _cv.wait(lock, []() -> bool {
            bool b = !_running || _value >= 10;
            printf("%s %4d %s : running:%d value:%d return:%d\n", __FILE__, __LINE__, __func__, _running, _value, b);
            return b;
        });
        printf("%s %4d %s : running:%d value:%d out\n", __FILE__, __LINE__, __func__, _running, _value);
        _value = 0;
    }
    printf("%s %4d %s : out\n", __FILE__, __LINE__, __func__);
}

int main(int argc, char* argv[])
{
    std::thread provider_th(provider);
    std::thread consumer_th(consumer);

    std::this_thread::sleep_for(std::chrono::seconds(10));

    _running = false;
    _cv.notify_all();

    provider_th.join();
    consumer_th.join();

    return 0;
}