WsaAsyncSelect编程模型

在我们的处理函数中可以如下监听客户端的连接：

SOCKET listenSock = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );
sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(7788);
sin.sin_addr.S_un.S_addr = INADDR_ANY;
int nRet = bind( listenSock, (sockaddr*)&sin, (int)(sizeof(sin)));
if ( nRet == SOCKET_ERROR )
{
DWORD errCode = GetLastError();
return;
}

listen( listenSock, 5);

int clientNum = 0;
sockaddr_in clientAddr;
int nameLen = sizeof( clientAddr );

while( clientNum < FD_SETSIZE )
{
SOCKET clientSock = accept( listenSock, (sockaddr*)&clientAddr, &nameLen );
//hWnd为接收系统发送的消息的窗口句柄
WSAAsyncSelect( clientSock, hWnd, UM_SOCK_ASYNCRECVMSG, FD_READ | FD_CLOSE );
clientNum++;
}

接下来，我们需要在我们的窗口添加对UM_SOCK_ASYNCRECVMSG消息的处理函数，在该函数中真正接收客户端发送过来的数据，在这个消息处理函数中的wparam参数表示的是客户端套接字，lparam参数表示的是发生的网络事件如：

SOCKET clientSock = (SOCKET)wParam;if ( WSAGETSELECTERROR( lParam ) ){closesocket( clientSock );return;}switch ( WSAGETSELECTEVENT( lParam ) ){case FD_READ:{char recvBuffer[1024] = {'\0'};int nRet = recv( clientSock, recvBuffer, 1024, 0 );if ( nRet > 0 ){szRecvMsg.AppendFormat(_T("Client %d Say:%s\r\n"), clientSock, recvBuffer );}else{//client disconnectszRecvMsg.AppendFormat(_T("Client %d Disconnect!\r\n"), clientSock );}}break;case FD_CLOSE:{closesocket( clientSock );szRecvMsg.AppendFormat(_T("Client %d Disconnect!\r\n"), clientSock );}break;}