WSAAsyncSelect Demo

 #include <WinSock2.h>
 #include <Windows.h>
 #include <StrSafe.h>

 #pragma comment(lib, "Ws2_32")

 #define WM_SOCKET WM_USER+1

 LRESULT CALLBACK WinProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 {
     switch (uMsg)
     {
     case WM_SOCKET:
         {
             if (WSAGETSELECTERROR(lParam))
             {
                 shutdown(wParam, SD_BOTH);
                 closesocket(wParam);
                 return ;
             }

             switch (WSAGETSELECTEVENT(lParam))
             {
             case FD_ACCEPT:
                 {
                     SOCKET client = accept(wParam, NULL, NULL);
                     WSAAsyncSelect(client, hWnd, WM_SOCKET, FD_READ | FD_WRITE | FD_CLOSE);
                 }
                 break;
             case FD_WRITE:
                 break;
             case FD_READ:
                 {
                     CHAR szText[] = {  };
                     if (SOCKET_ERROR == recv(wParam, szText, , ))
                     {
                         shutdown(wParam, SD_BOTH);
                         closesocket(wParam);
                     }
                     else
                     {
                         CHAR szMsg[] = "接收数据：";
                         strcat_s(szMsg, szText);
                         MessageBoxA(hWnd, szMsg, "结果", MB_OK);
                     }
                 }
                 break;
             case FD_CLOSE:
                 shutdown(wParam, SD_BOTH);
                 closesocket(wParam);
                 break;
             }
         }
         return ;
     case WM_DESTROY:
         PostQuitMessage();
         return ;
     default:
         return DefWindowProc(hWnd, uMsg, wParam, lParam);
     }
     return DefWindowProc(hWnd, uMsg, wParam, lParam);
 }

 int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPreInstance, PSTR pcszCommand, int iShow)
 {
     TCHAR szAppName[] = TEXT("WSAAsyncSelect");
     WNDCLASSEX wndClsEx;

     wndClsEx.cbClsExtra = ;
     wndClsEx.cbSize = sizeof(wndClsEx);
     wndClsEx.cbWndExtra = ;
     wndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
     wndClsEx.hCursor = LoadCursor(NULL, IDC_ARROW);
     wndClsEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
     wndClsEx.hIconSm = NULL;
     wndClsEx.hInstance = hInstance;
     wndClsEx.lpfnWndProc = WinProc;
     wndClsEx.lpszClassName = szAppName;
     wndClsEx.lpszMenuName = NULL;
     wndClsEx.style = CS_HREDRAW | CS_VREDRAW;

     if (!RegisterClassEx(&wndClsEx))
     {
         MessageBox(NULL, TEXT("注册窗口类失败,本程序需要在Windows NT系统上才能运行。"), TEXT("错误"), MB_OK | MB_ICONERROR);
         return ;
     }

     HWND hWnd = CreateWindowEx(
         ,
         szAppName,
         szAppName,
         WS_OVERLAPPEDWINDOW,
         CW_USEDEFAULT,
         CW_USEDEFAULT,
         CW_USEDEFAULT,
         CW_USEDEFAULT,
         NULL,
         NULL,
         hInstance,
         NULL);
     if (NULL == hWnd)
     {
         MessageBox(NULL, TEXT("创建窗口失败"), TEXT("错误"), MB_OK | MB_ICONERROR);
         return ;
     }

     ShowWindow(hWnd, iShow);
     UpdateWindow(hWnd);

     WSADATA wsaData;
     WSAStartup(WINSOCK_VERSION, &wsaData);

     SOCKET sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if (INVALID_SOCKET == sListen)
     {
         MessageBox(hWnd, TEXT("创建套接字失败"), TEXT("错误"), MB_OK | MB_ICONERROR);
         WSACleanup();
         return ;
     }

     SOCKADDR_IN sin;
     USHORT uPort = ;

     ZeroMemory(&sin, sizeof(sin));
     sin.sin_family = AF_INET;
     sin.sin_port = htons(uPort);
     sin.sin_addr.S_un.S_addr = INADDR_ANY;

     if (SOCKET_ERROR == bind(sListen, (PSOCKADDR)&sin, sizeof(sin)))
     {
         MessageBox(hWnd, TEXT("绑定套接字失败"), TEXT("错误"), MB_OK | MB_ICONERROR);
         shutdown(sListen, SD_RECEIVE);
         closesocket(sListen);
         WSACleanup();
         return ;
     }

     //将套接字设为窗口通知消息类型
     WSAAsyncSelect(sListen, hWnd, WM_SOCKET, FD_ACCEPT | FD_CLOSE);
     listen(sListen, );

     MSG msg;
     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }

     WSACleanup();

     return msg.wParam;
 }