Server

// C++ headers
#include <iostream>
#include <thread>
#include <mutex>
#include <list>
#include <chrono>

// SDL headers
#include <SDL2/SDL.h>
#include <SDL2/SDL_net.h>

using namespace std;

volatile bool listenForClientConnections = true;

void initSDL();
TCPsocket createServerSocket();

void listenForClients(TCPsocket socket)
{
    static const char *LOGIN_SUCCESS_MSG = "LoggedIn";

    cout << "Listening for clients...\n";

    char clientName[32];

    while (listenForClientConnections)
    {
        this_thread::sleep_for(chrono::milliseconds(500));

        TCPsocket client = SDLNet_TCP_Accept(socket);
        if (client == nullptr)
            continue;

        cout << "A client has connected!" << endl;
    }
}

int main()
{
    initSDL();

    TCPsocket serverSocket = createServerSocket();

    std::thread listenForClientsThread(listenForClients, serverSocket);

    getchar();
    listenForClientConnections = false;
    listenForClientsThread.join();

    SDLNet_TCP_Close(serverSocket);
}

void initSDL()
{
    // initialize SDL
    if( SDL_Init(SDL_INIT_EVERYTHING) != 0 )
    {
        cout << SDL_GetError() << "\n";
        exit(-1);
    }

    atexit(SDL_Quit);

    // initialize SDLNet
    if( SDLNet_Init() != 0 )
    {
        cout << SDLNet_GetError() << "\n";
        exit(-1);
    }

    atexit(SDL_Quit);
}

TCPsocket createServerSocket()
{
    IPaddress ip;
    ip.host = INADDR_ANY;
    ip.port = 12000;
    TCPsocket serverSocket = SDLNet_TCP_Open(&ip);

    if (serverSocket == nullptr)
    {
        cout << "Failed to create server socket: " << SDLNet_GetError() << endl;
        exit(-1);
    }

    return serverSocket;
}