AMY AMY - 2 months ago 13
C++ Question

asio "std::error_code" not resolved in eclipse?

I am completely newbie at ASIO c++ socket library. Manage to set up in eclipse with 'asio nonboost' and openssl library.
Now I am stuck on "std::error_code" not resolved.

Please assist, I had already west lots of time on this.

Following is the async_udp_echo_server page from asio I am trying to run.

#include <cstdlib>
#include <iostream>
#include "asio.hpp"

using asio::ip::udp;

class server
{
public:
server(asio::io_service& io_service, short port)
: socket_(io_service, udp::endpoint(udp::v4(), port))
{
do_receive();
}

void do_receive()
{
socket_.async_receive_from(
asio::buffer(data_, max_length), sender_endpoint_,
[this](std::error_code ec, std::size_t bytes_recvd)
{
if (!ec && bytes_recvd > 0)
{
do_send(bytes_recvd);
}
else
{
do_receive();
}
});
}

void do_send(std::size_t length)
{
socket_.async_send_to(
asio::buffer(data_, length), sender_endpoint_,
[this](std::error_code /*ec*/, std::size_t /*bytes_sent*/)
{
do_receive();
});
}

private:
udp::socket socket_;
udp::endpoint sender_endpoint_;
enum { max_length = 1024 };
char data_[max_length];
};

int main(int argc, char* argv[])
{
try
{
if (argc != 2)
{
std::cerr << "Usage: async_udp_echo_server <port>\n";
return 1;
}

asio::io_service io_service;

server s(io_service, std::atoi(argv[1]));

io_service.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}

return 0;
}

Answer

Since you are using "standalone" asio, error_code should be asio::error_code not std::error_code. Note: boost::system::error_code is required by boost::asio.

I use the following macros to switch between boost and "standalone" asio:

#ifdef ASIO_STANDALONE
  #include <asio.hpp>
  #define ASIO asio
  #define ASIO_ERROR_CODE asio::error_code
  #define ASIO_TIMER asio::steady_timer
#else
  #include <boost/asio.hpp>
  #define ASIO boost::asio
  #define ASIO_ERROR_CODE boost::system::error_code
  #define ASIO_TIMER boost::asio::deadline_timer
#endif
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