boost::asio doesn't work

Question

With the following class

the header:

namespace msgSrv {

class endPoint {

public:
    asio::ip::udp::endpoint ep;
    endPoint(std::string ip, int port);

};

class msgSrv {

private:
    asio::ip::udp::socket *asioSocket;
    asio::io_service *asioIoService;
    int listenPort;
    boost::array<char, 1> rcvBuff;
    asio::ip::udp::endpoint lastRcvdPcktEndp;
    char * sbuff;

public:

    boost::condition_variable cond;
    boost::mutex mut;
    msgSrv(int listenPort);
    virtual ~msgSrv();

    void start();
    void pckRcvd(const asio::error_code& error, std::size_t bytes_transferred);
    void sendTo(const char* buff, int len, endPoint ep);
    void sendHnd(const asio::error_code& error, std::size_t bytes_transferred);

};

}

the .cpp

#include "msgSrv.h"

namespace msgSrv {

endPoint::endPoint(const std::string ip, int port) {
    asio::ip::address addr = asio::ip::address::from_string(ip);
    ep = asio::ip::udp::endpoint(addr, port);
}

msgSrv::msgSrv(int listenPort) {
    // TODO Auto-generated constructor stub
    this->listenPort = listenPort;
    try {
     asioIoService = new asio::io_service();
     asioSocket = new asio::ip::udp::socket(*asioIoService,
       asio::ip::udp::endpoint(asio::ip::udp::v4(), listenPort)); //new asio::ip::udp::socket_(*asioIoService, udp::endpoint(udp::v4(), listenPort));
    } catch (std::exception &e) {
     std::cerr << "Error initializing ioservice or socket:" << e.what();
    }
    asioIoService->run();

}

msgSrv::~msgSrv() {
    // TODO Auto-generated destructor stub
    delete asioIoService;
    delete asioSocket;
}

void msgSrv::start() {

    asioSocket->async_receive_from(asio::buffer(rcvBuff), lastRcvdPcktEndp,
      boost::bind(&msgSrv::pckRcvd, this, asio::placeholders::error,
        asio::placeholders::bytes_transferred));

}

void msgSrv::pckRcvd(const asio::error_code& error,
     std::size_t bytes_transferred) {
    std::cout << "Rcvd! " << lastRcvdPcktEndp.address().to_string() << ":"
      << lastRcvdPcktEndp.port() << "\n";
}

void msgSrv::sendTo(const char* buff, int len, endPoint ep) {
    sbuff = new char[len];
    mempcpy(sbuff, buff, len);
    asioSocket->async_send_to(asio::buffer(sbuff, len), ep.ep, boost::bind(
      &msgSrv::sendHnd, this, asio::placeholders::error,
      asio::placeholders::bytes_transferred));

}

void msgSrv::sendHnd(const asio::error_code& error,
     std::size_t bytes_transferred) {
    std::cout << "Snt!\n";

    delete sbuff;
}

}

and the following "main" file:

int main()
{
    msgSrv::msgSrv aa(4450);
    aa.start();
    msgSrv::endPoint ep("127.0.0.1", 4450);
    std::string a("Prova!");
    int len = a.length();
    aa.sendTo(a.c_str(), len, ep);
    std::cout << "sent...\n";
    std::cout << "notified...\n";
}

all I get is:

terminate called after throwing an instance of 'asio::system_error'
  what():  mutex: Invalid argument
sent...
notified...

What's wrong?? I tried even to put a while(1) in the main, to see if something happens... I even tried to put a condition in the main that is unlocked by the receive handler... all remains locked... So what??? No idea!

Answer 1

I don't see you actually locking any muxtex, so that error is strange.

However your problem is to calling asioIoService->run() inside the constructor, witch fall in infinite loop. The solution is to create a new boost::thread, witch call asioIoService->run() itself. This thread will be processing all jobs. You may also call asio::io_service::run() with more then one thread, to get processing on more then one job at the same time.

m_thread = new boost::thread(boost::bind(&asio::io_service::run,asioIoService));

Calling asioIoService->stop() will force exit of asio::io_service::run(), thus closing the thread. You must join this thread to ensure that thread terminates before destroying asioIoService pointer in the destructor of your msgSrv class.