Windows Socket编程TCP范例之三(WSAAsyncSelect)

        WSAAsyncSelect模型允许应用程序以Windows消息的形式接收网络事件通知.这个模型是为了适应Windows的消息驱动环境而设置的,现在许多对性能要求不高的网络应用程序都采用WSAAsyncSelect模型.MFC中的CSocket类也使用了它.

        以下示例还是实现和前两篇文章（之一&之二）一样的功能：Client端连接Server端,向Server端发送数据。Server端接受Client端发送过来的数据并输出。Server端还是单线程处理多Client端连接的情况。

Server.cpp-----------------------------------------------------------------------------------------

1、在main中创建窗口但不调用ShowWindow即隐藏了窗口。由于是控制函程序，所以还是有控制函窗口的。

2、在ServerSocketProc中去初始化Windows Socket库、创建Socket、绑定Socket、监听Socket。

3、在窗口函数中处理Socket相关的消息

4、Client端通过closesocket关闭套接字会进入到以下的FD_CLOSE事件输出："FD_CLOSE"

而直接关闭Client端会使WSAGETSELECTERROR(lParam)为真，也就会输出："WSAGETSELECTERROR get error"

#include <windows.h>
#include <iostream>
using namespace std;

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int ServerSocketProc(HWND);

#pragma comment(lib, "Ws2_32.lib")  
  
#define WM_SOCKET WM_USER + 100
#define PORT_NO 6000  
#define BACKLOG 10  

// 全局变量
SOCKET gSockSrv;

int main()
{
	static TCHAR lpszAppName[] = TEXT("TestWin");
	HWND      hwnd;
	MSG       msg;
	WNDCLASS  wc;

	wc.style         = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc   = WndProc;
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = NULL;
	wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
	wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc.lpszMenuName  = NULL;
	wc.lpszClassName = lpszAppName;

	// 注册窗口类
	if (!RegisterClass(&wc))
	{
		MessageBox(NULL, TEXT("This program requires Windows NT!"),
			lpszAppName, MB_ICONERROR);
		return 0;
	}

	// 创建应用程序主窗口
	hwnd = CreateWindow(lpszAppName,
		TEXT("Server"),
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		NULL,
		NULL,
		NULL,
		NULL);
	if (NULL == hwnd)
	{
		MessageBox(NULL, TEXT("CreateWindow failed."),
			lpszAppName, MB_ICONERROR);
		return 0;
	}

	// 创建Socket服务
	int ret = ServerSocketProc(hwnd);
	if (0 != ret)
	{
		MessageBox(NULL, TEXT("ServerSocketProc failed."),
			lpszAppName, MB_ICONERROR);
		return 0;
	}

	// 消息循环 
	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

    // 清理资源------  
	closesocket(gSockSrv);  
	WSACleanup();

	return msg.wParam;
}

//
// 窗口过程函数
//
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
	case WM_SOCKET:	   // 处理Socket信息
		{
			int ret;
			SOCKET sock = wParam;

			// 查看是否出错
			if(WSAGETSELECTERROR(lParam))
			{
				closesocket(sock);
				cout << "WSAGETSELECTERROR get error" << endl;
				if (sock == gSockSrv)
				{
					DestroyWindow(hwnd);
				}
				return 0;
			}
			// 处理发生的事件
			switch(WSAGETSELECTEVENT(lParam))
			{
			case FD_ACCEPT:		// 监听中的套接字检测到有连接进入
				{
					int len=sizeof(SOCKADDR);
					SOCKADDR_IN addrClient;
					SOCKET sockConn = accept(sock, (SOCKADDR*)&addrClient, &len);

					if (INVALID_SOCKET == sockConn)  
                    {  
                        cout << "accept() failed:" << WSAGetLastError() << endl;  
                        return 0;  
                    }  

					cout << "接受到新连接:" << inet_ntoa(addrClient.sin_addr) << endl;

					WSAAsyncSelect(sockConn, hwnd, WM_SOCKET, FD_READ | FD_WRITE | FD_CLOSE);
				}
				break;

			case FD_WRITE:
				{
				}
				break;

			case FD_READ:
				{
					char recvBuffer[MAX_PATH] = {0};  
                    ret = recv(sock, recvBuffer, sizeof(recvBuffer), 0);
					if (ret == 0)  
                    {  
                        cout << "Connection has been gracefully closed." << endl;   
                        closesocket(sock);  
                        return 0;  
                    }  
                    else if (ret == SOCKET_ERROR)   
                    {  
                        cout << "Connection has been closed ungracefully." << endl;   
                        closesocket(sock);  
                        return 0;  
                    }  
  
                    cout << "Receive Data from Client:" << recvBuffer << endl;  
				}
				break;

			case FD_CLOSE:
				{ 
					cout << "FD_CLOSE" << endl;
					closesocket(sock);
				}
				break;
			}
		}
		break;

	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}

	return DefWindowProc(hwnd, message, wParam, lParam);
}

int ServerSocketProc(HWND hwnd)
{
	cout << "ServerSocketProc-----------------------------------------BEG" << endl;

	WSADATA wsaData;
	int ret;
	WORD wVersionRequested = MAKEWORD(2, 2);
	SOCKET sockSrv;
	SOCKADDR_IN addrSrv;
	HANDLE hThread = NULL;

	// 初始化Windows Socket------
	ret = WSAStartup(wVersionRequested, &wsaData);
	if (ret != 0) 
	{
		cout << "WSAStartup() failed:" << WSAGetLastError() << endl;
		return -1;
	}

	// 创建Socket------
	sockSrv = socket(AF_INET, SOCK_STREAM, 0);
	if (INVALID_SOCKET == sockSrv)
	{
		cout << "socket() failed:" << WSAGetLastError() << endl;
		WSACleanup();
		return -1;
	}
	gSockSrv = sockSrv;
	addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	addrSrv.sin_family = AF_INET;
	addrSrv.sin_port = htons(PORT_NO);

	// Bind Socket------
	ret = bind(sockSrv, (SOCKADDR*)&addrSrv, sizeof(SOCKADDR));
	if (SOCKET_ERROR == ret)
	{
		cout << "bind() failed:" << WSAGetLastError() << endl;
		closesocket(sockSrv);
		WSACleanup();
		return -1;
	}

	// 监听------
	ret = listen(sockSrv, BACKLOG);
	if (SOCKET_ERROR == ret)
	{
		cout << "listen() failed:" << WSAGetLastError() << endl;
		closesocket(sockSrv);
		WSACleanup();
		return -1;
	}

	// WSAAsyncSelect------
	WSAAsyncSelect(sockSrv, hwnd, WM_SOCKET, FD_ACCEPT | FD_CLOSE); 
	cout << "ServerSocketProc-----------------------------------------END" << endl;
	cout<< "Server started......" << endl;

	return 0;
}

Client.cpp---------------------------------------------------------------------------------------------------------

#include <iostream>
#include <windows.h>

using namespace std;

#pragma comment(lib, "Ws2_32.lib")

#define PORT_NO 6000
#define SRV_IP_ADDR "127.0.0.1"

int main(int argc, char* argv[])
{
	int ret;
	WSADATA wsaData;
	WORD wVersionRequested = MAKEWORD(2, 2);
	SOCKET sockClient;
	SOCKADDR_IN addrSrv;
	
	// 初始化Windows Socket------
	ret = WSAStartup(wVersionRequested, &wsaData);
	if (ret != 0) 
	{
		cout << "WSAStartup() failed:" << WSAGetLastError() << endl;
		return -1;
	}

    // 创建Socket------
	sockClient = socket(AF_INET, SOCK_STREAM, 0);
	if (INVALID_SOCKET == sockClient)
	{
		cout << "socket() failed:" << WSAGetLastError() << endl;
		WSACleanup();
		return -1;
	}

	addrSrv.sin_addr.S_un.S_addr = inet_addr(SRV_IP_ADDR);
	addrSrv.sin_family = AF_INET;
	addrSrv.sin_port = htons(PORT_NO);

	// 连接------
	ret = connect(sockClient, (SOCKADDR*)&addrSrv, sizeof(SOCKADDR));
	if (SOCKET_ERROR == ret)
	{
		cout << "connect() failed:" << WSAGetLastError() << endl;
		closesocket(sockClient);
		WSACleanup();
		return -1;
	}
	else
	{
		cout << "connect() successfully." << endl;
	}

	// 发送数据------
	char sendBuf[MAX_PATH] = {0};
	while (1)
	{
		cin.getline(sendBuf, sizeof(sendBuf));
		if (strcmp(sendBuf, "exit") == 0)
		{
			break;
		}
		ret = send(sockClient, sendBuf, strlen(sendBuf)+1, 0);
		if (SOCKET_ERROR == ret)
		{
			cout << "send() failed:" << WSAGetLastError() << endl;
			closesocket(sockClient);
			WSACleanup();
			return -1;
		}
	}

	// 清理资源-------
	closesocket(sockClient);
	WSACleanup();

	cout << "exit..." << endl;
	return 0;
}

示例图片：------------------------------------------------------------------------------------------------