how to accept multi thread's connection request in FD_ACCEPT? - c

Question

If I have n Client connect the Server,how to accept it in FD_ACCEPT and how to receive it in FD_READ and how to send it in FD_WRITE and not use like this form
e.p.
while(1){
ClientSocket=accept(ListenSocket,0,0);
if(ClientSocket!=INVALID_SOCKET)
_beginthreadex();
}
how to achieve it in this form
case WM_SERVER_SOCKET:
wEvent = WSAGETSELECTEVENT(lParam);//LOWORD
switch (wEvent) {
case FD_ACCEPT:
ClientSocket=accept(ListenSocket, nullptr, nullptr);
break;
case FD_READ:
break;
case FD_WRITE:
break;
case FD_CLOSE:
break;
}
break;
or this form just can handle one Client connection?
is it necessary do it in this form?
I want use it for a simple chat application

Answer 1

WSAAsyncSelect() is what you are looking for, eg:
WNDCLASS cls = {0};
cls.lpfnWndProc = &SocketWndProc;
cls.hInstance = ...;
cls.lpszClassName = TEXT("MySocketWnd");
RegisterClass(&cls);
HWND hWnd = CreateWindowEx(0, cls.lpszClassName, nullptr, 0, 0, 0, 0, 0, HWND_MESSAGE, nullptr, cls.hInstance, nullptr);
SOCKET ListenSocket = socket(...);
bind(ListenSocket, ...);
listen(ListenSocket, ...);
WSAAsyncSelect(ListenSocket, hWnd, WM_SERVER_SOCKET, FD_ACCEPT | FD_READ | FD_WRITE | FD_CLOSE);
MSG msg;
while (GetMessage(&msg, nullptr, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
closesocket(ListenSocket);
DestroyWindow(hWnd);
LRESULT CALLBACK SocketWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
if (uMsg != WM_SERVER_SOCKET)
return DefWindowProc(hWnd, uMsg, wParam, lParam);
SOCKET sckt = (SOCKET) wParam;
WORD wEvent = WSAGETSELECTEVENT(lParam);
WORD wError = WSAGETSELECTERROR(lParam);
if (wError != 0)
{
// wEvent on sckt failed, do something ...
return 0;
}
switch (wEvent)
{
case FD_ACCEPT:
{
// sckt has a pending client...
SOCKET ClientSocket = accept(sckt,...);
// do something with new client (add it to a tracking list, etc) ...
break;
}
case FD_READ:
{
// sckt has pending data...
int numBytes = recv(sckt, ...);
// process data as needed...
break;
}
case FD_WRITE:
{
// sckt can receive data, send any pending data ...
break;
}
case FD_CLOSE:
{
// sckt has disconnected, do something (remove it from list, etc)...
break;
}
}
return 0;
}