Async callbacks

main.cpp

#include <iostream>
#include <chrono>
#include <thread>

#define UV_OVERLOAD_OSTREAM

#include "uv++.hpp"

using namespace std;

int main() {
    //Just use the default loop
    auto loop = uv::default_loop();

    //Create an asynchronous task
    auto a = loop->async<int, string>( [&]( auto, int i ) {
        cout << "Sent: " << i << endl;

        return "Hello, World!";
    } );

    /*
     * An async trigger MUST be called from another thread if it blocks to receive a return value.
     *
     * Otherwise, it'll block the same thread the event looping is running on and deadlock everything.
     * */
    thread( [=]() {
        //Trigger the asynchronous task and wait on the result
        cout << "Returned: " << a->send( 42 ).get() << endl;

    } ).detach();

    //Start the event loop
    loop->start();

    return 0;
}

output.txt

Sent: 42
Returned: Hello, World!