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Subject: Re: [Boost-users] async_send handler problem
From: Alexander Carôt (Alexander_Carot_at_[hidden])
Date: 2013-12-16 14:47:06

P.S.: This is a way simpler program, which behaves in the same way: When
launching the thread before the async_send call it does not work - when
launching it after it does:

/* async_send_to udp example
  * compile with
  * g++ -o udpserver2 udpserver2.cpp -lboost_system -lboost_signals
#include <iostream>
#include <boost/array.hpp>
#include <boost/asio.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/thread.hpp>

boost::asio::io_service io_service;

void handle_send(const boost::system::error_code& error, std::size_t
  std::cout << "async_send_to return " << error << ": " <<
bytes_transferred << " transmitted" << std::endl;

/* ./udpserver <host> <port> */

int main(int argc, char *argv[])
    //boost::thread t = boost::thread
(boost::bind(&boost::asio::io_service::run, &io_service));

    boost::asio::ip::udp::socket socket(io_service);
    boost::asio::ip::udp::endpoint remote_endpoint;;

    remote_endpoint = boost::asio::ip::udp::endpoint(

    std::cout << "Send to " << remote_endpoint << std::endl;

    socket.async_send_to(boost::asio::buffer("message", 7),
    boost::bind(&handle_send, boost::asio::placeholders::error,

    boost::thread t = boost::thread
(boost::bind(&boost::asio::io_service::run, &io_service));
  return 0;

>>>>void sender::sendIt(char *charBuffer){
>>>> sj->dFC->;
>>>You should not call io_service::run() inside this function. The normal
>>>pattern is to set up your network code, e.g. from main(), and then call
>>>run() after setup. This call will block (and all Asio callbacks will be
>>>executed from this thread.) If you do not want your main thread to
>>>handle the network code, then you can launch in a separate thread (as
>>>previously suggested.)
>Yes, I truly understand this but for some weired reason this doesn't work
>at all. In my case I launch the run function in the constructor of the
>main class right after the sender class had been instantiated:
> dFC->mySender = new sender(this);
> boost::thread t =
> t.join();
> // OR dFC->;
>In there anything wrong with this ?

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