glibmm 2.56.0

thread/thread.cc

A glibmm thread example.

#include <condition_variable>
#include <iostream>
#include <memory>
#include <mutex>
#include <queue>
#include <thread>
#if defined(_MSC_VER) && (_MSC_VER < 1900)
/* For using noexcept on Visual Studio 2013 */
#include <glibmmconfig.h>
#endif
#include <glibmm/init.h>
#include <glibmm/random.h>
#include <glibmm/timer.h>
namespace
{
class MessageQueue
{
public:
MessageQueue();
~MessageQueue();
void producer();
void consumer();
private:
std::mutex mutex_;
std::condition_variable cond_push_;
std::condition_variable cond_pop_;
std::queue<int> queue_;
};
MessageQueue::MessageQueue()
{
}
MessageQueue::~MessageQueue()
{
}
void
MessageQueue::producer()
{
Glib::Rand rand(1234);
for (auto i = 0; i < 200; ++i)
{
{
std::unique_lock<std::mutex> lock(mutex_);
cond_pop_.wait(lock, [this]() -> bool { return queue_.size() < 64; });
queue_.push(i);
std::cout << '*';
std::cout.flush();
// We unlock before notifying, because that is what the documentation suggests:
// http://en.cppreference.com/w/cpp/thread/condition_variable
lock.unlock();
cond_push_.notify_one();
}
if (rand.get_bool())
continue;
Glib::usleep(rand.get_int_range(0, 100000));
}
}
void
MessageQueue::consumer()
{
Glib::Rand rand(4567);
for (;;)
{
{
std::unique_lock<std::mutex> lock(mutex_);
cond_push_.wait(lock, [this]() -> bool { return !queue_.empty(); });
const int i = queue_.front();
queue_.pop();
std::cout << "\x08 \x08";
std::cout.flush();
// We unlock before notifying, because that is what the documentation suggests:
// http://en.cppreference.com/w/cpp/thread/condition_variable
lock.unlock();
cond_pop_.notify_one();
if (i >= 199)
break;
}
if (rand.get_bool())
continue;
Glib::usleep(rand.get_int_range(10000, 200000));
}
}
}
int
main(int, char**)
{
Glib::init();
MessageQueue queue;
// TODO: Use std::make_unique() when we use C++14:
const auto producer =
std::unique_ptr<std::thread>(new std::thread(&MessageQueue::producer, &queue));
const auto consumer =
std::unique_ptr<std::thread>(new std::thread(&MessageQueue::consumer, &queue));
producer->join();
consumer->join();
std::cout << std::endl;
return 0;
}