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How to build an echo server and client using asio local datagram?

// server

#include <boost/asio.hpp>

int main()

::unlink("local_socket");
boost::asio::io_service io_service;
boost::asio::local::datagram_protocol::endpoint endpoint("local_socket");
boost::asio::local::datagram_protocol::socket socket(io_service, endpoint);

char recv_buf[1024];
while (1)

boost::asio::local::datagram_protocol::endpoint senderEndpoint;
size_t len = socket.receive_from(
boost::asio::buffer(recv_buf, 1024), senderEndpoint);
printf("***%s###n", senderEndpoint.path().c_str());

socket.send_to(
boost::asio::buffer(recv_buf, len), senderEndpoint);


return 0;



// client

#include <boost/asio.hpp>

enum max_length = 1024 ;

int main(int argc, char* argv)

boost::asio::io_service io_service;
boost::asio::local::datagram_protocol::endpoint endpoint("local_socket");
boost::asio::local::datagram_protocol::socket socket(io_service);
socket.open();

std::cout << "Enter message: ";
char request[max_length];
std::cin.getline(request, max_length);
size_t request_length = strlen(request);

socket.send_to(
boost::asio::buffer(request, request_length), endpoint);

char reply[max_length];
size_t reply_length = socket.receive_from(
boost::asio::buffer(reply, max_length), endpoint);

std::cout << "Reply is: ";
std::cout.write(reply, reply_length);
std::cout << "n";

return 0;



When I use client to send "123", and server is coredump with:

***### terminate called after throwing an instance of 'boost::exception_detail::clone_impl

' what(): send_to: Invalid argument Aborted

2 Answers
2

Find the answer here.
client,server.

The reason the server aborting is because the senderEndpoint is not being populated by the call to receive_from - the client socket is not bound to anything so it does not send a file descriptor on which to receive responses. If we refactor the client like this:

senderEndpoint

receive_from

#include <iostream>

#include <boost/asio.hpp>

enum max_length = 1024 ;

int main(int argc, char* argv)

boost::asio::io_service io_service;
boost::asio::local::datagram_protocol::endpoint server_endpoint("local_socket");
// Create client endpoint on which to receive response
std::string client_addr = "local_socket.";
client_addr += std::to_string(::getpid());
::unlink(client_addr.c_str());
boost::asio::local::datagram_protocol::endpoint client_endpoint(client_addr.c_str());
boost::asio::local::datagram_protocol::socket socket(io_service, client_endpoint);

std::cout << "Enter message: ";
char request[max_length];
std::cin.getline(request, max_length);
size_t request_length = strlen(request);

socket.send_to(
boost::asio::buffer(request, request_length), server_endpoint);

char reply[max_length];
size_t reply_length = socket.receive_from(
boost::asio::buffer(reply, max_length), client_endpoint);

std::cout << "Reply is: ";
std::cout.write(reply, reply_length);
std::cout << "n";

return 0;



then it works as expected:

Enter message: 123
***local_socket.29635###
Reply is: 123


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