Boost_Asio(3) post和dispatch

// asio_post_dispatch.cpp : 定义控制台应用程序的入口点。
//
/*
	代码使用智能指针控制io_service，使用mutex控制各个进程间的输出互斥。work类维持io_service的生命周期, 然后使用post添加执行任务。

	在此基础上我们再查看post与dispatch的区别：

	post 优先将任务排进处理队列，然后返回，任务会在某个时机被完成。

	dispatch会即时请求io_service去调用指定的任务。
*/
#include "stdafx.h"
#include 
#include 
#include 
#include 
#include 
#include 

boost::mutex global_stream_lock;

void WorkerThread(boost::shared_ptr< boost::asio::io_service > io_service)
{
	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] Thread Start" << std::endl;
	global_stream_lock.unlock();

	io_service->run();

	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] Thread Finish" << std::endl;
	global_stream_lock.unlock();
}

size_t fib(size_t n)
{
	if (n <= 1)
	{
		return n;
	}
	boost::this_thread::sleep(
		boost::posix_time::milliseconds(1000)
		);
	return fib(n - 1) + fib(n - 2);
}

void CalculateFib(size_t n)
{
	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] Now calculating fib( " << n << " ) " << std::endl;
	global_stream_lock.unlock();

	size_t f = fib(n);

	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] fib( " << n << " ) = " << f << std::endl;
	global_stream_lock.unlock();
}

int main(int argc, char * argv[])
{
	boost::shared_ptr< boost::asio::io_service > io_service(
		new boost::asio::io_service
		);
	boost::shared_ptr< boost::asio::io_service::work > work(
		new boost::asio::io_service::work(*io_service)
		);

	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] The program will exit when all work has finished."
		<< std::endl;
	global_stream_lock.unlock();

	boost::thread_group worker_threads;
	for (int x = 0; x < 2; ++x)
	{
		worker_threads.create_thread(
			boost::bind(&WorkerThread, io_service)
			);
	}

	io_service->post(boost::bind(CalculateFib, 3));
	io_service->post(boost::bind(CalculateFib, 4));
	io_service->post(boost::bind(CalculateFib, 5));

	work.reset();

	worker_threads.join_all();

	system("pause");
	return 0;
}

// aiso_dispatch.cpp : 定义控制台应用程序的入口点。
//
/*
	我们可以看到结果是先显示dispatch的结果然后才显示post结果，与预想的是一致的.
*/
#include "stdafx.h"

#include 
#include 
#include 
#include 
#include 
#include 

boost::mutex global_stream_lock;

void WorkerThread(boost::shared_ptr< boost::asio::io_service > io_service)
{
	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] Thread Start" << std::endl;
	global_stream_lock.unlock();

	io_service->run();

	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] Thread Finish" << std::endl;
	global_stream_lock.unlock();
}

void Dispatch(int x)
{
	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id() << "] "
		<< __FUNCTION__ << " x = " << x << std::endl;
	global_stream_lock.unlock();
}

void Post(int x)
{
	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id() << "] "
		<< __FUNCTION__ << " x = " << x << std::endl;
	global_stream_lock.unlock();
}

void Run3(boost::shared_ptr< boost::asio::io_service > io_service)
{
	for (int x = 0; x < 3; ++x)
	{
		io_service->dispatch(boost::bind(&Dispatch, x * 2));
		io_service->post(boost::bind(&Post, x * 2 + 1));
		boost::this_thread::sleep(boost::posix_time::milliseconds(1000));
	}
}

int main(int argc, char * argv[])
{
	boost::shared_ptr< boost::asio::io_service > io_service(
		new boost::asio::io_service
		);
	boost::shared_ptr< boost::asio::io_service::work > work(
		new boost::asio::io_service::work(*io_service)
		);

	global_stream_lock.lock();
	std::cout << "[" << boost::this_thread::get_id()
		<< "] The program will exit when all  work has finished." << std::endl;
	global_stream_lock.unlock();

	boost::thread_group worker_threads;
	for (int x = 0; x < 1; ++x)
	{
		worker_threads.create_thread(boost::bind(&WorkerThread, io_service));
	}

	io_service->post(boost::bind(&Run3, io_service));

	work.reset();

	worker_threads.join_all();

	system("pause");
	return 0;
}