C++ boost tcp-server - c++

Question

I tried to create an tcp-server with the boost libs. I basically took example code from boost(the whole code was in 1 file there) and split it up into a class.
Seems like something went wrong there and i dont really know whats missing.
The main error is at the end of "tcp_server.cpp" i put the error message into a comment there. It looks like he doesnt know the function session(at least thats how i interpreted it), i get the same error with "tcp_server::session" and "this->session".
The second thing is an error i get from "e.what()"(cannot resolve identifer what). It worked in the example code and i didnt change anything at the exceptions.
Thanks in advance.
tcp_server.h
#include <cstdlib>
#include <iostream>
#include <exception>
#include <boost/bind.hpp>
#include <boost/smart_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/thread/thread.hpp>
using boost::asio::ip::tcp;
class tcp_server
{
public:
typedef boost::shared_ptr<tcp::socket> socket_ptr;
tcp_server();
~tcp_server();
void server(boost::asio::io_service&);
private:
const short port = 8888;
const int max_length = 1024;
void session(socket_ptr);
};
tcp_server.cpp
#include "tcp_server.h"
tcp_server::tcp_server()
{
}
tcp_server::~tcp_server()
{
}
void tcp_server::session(socket_ptr sock)
{
try
{
for (;;)
{
char data[max_length];
boost::system::error_code error;
size_t length = sock->read_some(boost::asio::buffer(data), error);
if (error == boost::asio::error::eof)
break; // Connection closed cleanly by peer.
else if (error)
throw boost::system::system_error(error); // Some other error.
boost::asio::write(*sock, boost::asio::buffer(data, length));
}
}
catch (std::exception& e)
{
std::cerr << "Exception in thread: " << e.what() << "\n"; //
}
}
void tcp_server::server(boost::asio::io_service& io_service)
{
tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port));
for (;;)
{
socket_ptr sock(new tcp::socket(io_service));
a.accept(*sock);
boost::thread t(boost::bind(session, sock)); //error: no matching function for call to ‘bind(<unresolved overloaded function type>, tcp_server::socket_ptr&)’`
}
}
main.cpp
#include "tcp_server.h"
int main() {
tcp_server server;
try
{
boost::asio::io_service io_service;
server.server(io_service);
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}

Answer 1

You cannot bind the non-static member function tcp_server::session because it cannot be called without an object instance, which is not available to the bind.
You can however make tcp_server::session static (in tcp_header.h) to fix this:
static void session(socket_ptr);
Edit:
You can bind session as non-static member using:
boost::thread t(boost::bind(&tcp_server::session, this, sock));