如何在C ++中使函数异步? [英] How do I make a function asynchronous in C++?

问题描述

我想调用一个异步的函数(完成此任务后，我将提供一个回调).

I want to call a function which will be asynchronous (I will give a callback when this task is done).

我想在单线程中执行此操作.

I want to do this in single thread.

推荐答案

可以使用现代C ++甚至是旧C ++和某些

This can be done portably with modern C++ or even with old C++ and some boost. Both boost and C++11 include sophisticated facilities to obtain asynchronous values from threads, but if all you want is a callback, just launch a thread and call it.

1998 C ++/boost方法:

1998 C++/boost approach:

#include <iostream>
#include <string>
#include <boost/thread.hpp>
void callback(const std::string& data)
{
    std::cout << "Callback called because: " << data << '\n';
}
void task(int time)
{
    boost::this_thread::sleep(boost::posix_time::seconds(time));
    callback("async task done");
}
int main()
{
    boost::thread bt(task, 1);
    std::cout << "async task launched\n";
    boost::this_thread::sleep(boost::posix_time::seconds(5));
    std::cout << "main done\n";
    bt.join();
}

2011 C ++方法(使用gcc 4.5.2，需要使用此#define)

2011 C++ approach (using gcc 4.5.2, which needs this #define)

#define _GLIBCXX_USE_NANOSLEEP
#include <iostream>
#include <string>
#include <thread>
void callback(const std::string& data)
{
    std::cout << "Callback called because: " << data << '\n';
}
void task(int time)
{
    std::this_thread::sleep_for(std::chrono::seconds(time));
    callback("async task done");
}
int main()
{
    std::thread bt(task, 1);
    std::cout << "async task launched\n";
    std::this_thread::sleep_for(std::chrono::seconds(5));
    std::cout << "main done\n";
    bt.join();
}

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