asio tcp server hanging - c++

Question

I know this is probably a really simple problem but ive been trying to get the asio examples to work correctly for over a week now. whenever I run the program, the terminal hangs and dosent print anything and dosent send any info to the client. Im using Ubuntu Linux and a basic compiler command
g++ main.cpp -o main.exe -I include
#define ASIO_STANDALONE;
#include <ctime>
#include <iostream>
#include <string>
#include <asio.hpp>
using asio::ip::tcp;
int main()
{
try
{
asio::io_context io_context;
tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), 1326));
for (;;)
{
std::cout << "hi";
tcp::socket socket(io_context);
acceptor.accept(socket);
std::string message = "e";
asio::error_code ignored_error;
asio::write(socket, asio::buffer(message), ignored_error);
break;
}
}
catch (std::exception& e)
{
std::cerr << e.what() << std::endl;
}
return 0;
}
any help would be much appreciated

Answer 1

the terminal hangs and dosent print anything and dosent send any info to the client
You need to connect a client first, because the first thing you do is a blocking accept which never completes unless a connection arrives.
I've compiled your program (with minor modification for Boost Asio):
Live On Coliru
//#define ASIO_STANDALONE
#include <boost/asio.hpp>
#include <ctime>
#include <iostream>
#include <string>
namespace asio = boost::asio;
using asio::ip::tcp;
using boost::system::error_code;
int main() {
try {
asio::io_context io_context;
tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), 1326));
for (;;) {
tcp::socket socket(io_context);
acceptor.accept(socket);
std::cout << "hi " << socket.remote_endpoint() << std::endl;
std::string message = "server message works\n";
error_code ignored_error;
asio::write(socket, asio::buffer(message), ignored_error);
break;
}
} catch (std::exception const& e) {
std::cerr << e.what() << std::endl;
}
}
Using netcat to emulate a client:
nc 127.0.0.1 1326 -w 1 <<< "Hello world"
We see:
hi 127.0.0.1:45448
server message works
Or more clearly in separate terminals: