C++中I/O模型之select模型实例

本文实例讲述了C++中I/O模型的select模型用法。分享给大家供大家参考。具体实现方法如下：

代码如下:

void main() 
{ 
    CInitSock initSock; 
    USHORT nPort = 9999; //监听的端口 
    SOCKET sListen = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); 
    if (sListen == INVALID_SOCKET) 
    { 
        printf("socket error..."); 
        return; 
    } 
    sockaddr_in servAddr = {0}; 
    servAddr.sin_family = AF_INET; 
    servAddr.sin_port = ::htons(nPort); 
    servAddr.sin_addr.S_un.S_addr = INADDR_ANY;  
    if (SOCKET_ERROR == ::bind(sListen, (sockaddr*)&servAddr, sizeof(servAddr))) 
    { 
        int nError = ::GetLastError(); 
        printf("connect error.."); 
        return; 
    } 
    ::listen(sListen, 5); 
 
     
    //select模型处理过程 
    //1.初始化套接字集合，添加监听socket到这个集合 
    fd_set  fdSocket; 
    FD_ZERO(&fdSocket); 
    FD_SET(sListen, &fdSocket); 
    while (TRUE) 
    { 
        //2. 将集合的一个拷贝传递给select函数 
        //当有事件发生时，select移除未决的socket,然后返回   就是说select返回时 集合的中socket就是发生事件的socket 
        fd_set fdRead = fdSocket; 
        int nRet = ::select(0, &fdRead, NULL, NULL, NULL); 
        if (nRet > 0) 
        { 
            //通过比较原来的fdSocket集合与经过处理的fdRead集合 
            for (UINT i=0;i<fdSocket.fd_count;i++) 
            { 
                if (FD_ISSET(fdSocket.fd_array[i], &fdRead)) //就是这个触发了 
                { 
                    if (fdSocket.fd_array[i] == sListen) //监听套接字接收到新连接  为神马分两种情况：因为触发Read集合的情况有两种：有连接来了或数据可读了.... 
                    { 
                        // 
                        if (fdSocket.fd_count < FD_SETSIZE) //FD_SETSIZE=64 
                        { 
                            sockaddr_in addrRemote = {0}; 
                            int nAddrLen = sizeof(addrRemote); 
                            SOCKET sNew = ::accept(sListen, (sockaddr*)&addrRemote, &nAddrLen); 
                            FD_SET(sNew, &fdSocket); 
                        } 
                        else     
                        { 
                            printf("too many connection...error"); 
                            continue; 
                        } 
                    } 
                    else  //有可读的 
                    { 
                        char szContent[256]={0}; 
                        int nRecv = ::recv(fdSocket.fd_array[i], szContent, sizeof(szContent), 0); 
                        if (nRecv > 0) 
                        { 
                            szContent[nRecv] = '\0'; 
                            printf("recv data:%s", szContent); 
                        } 
                        else //没读到数据 
                        { 
                            ::closesocket(fdSocket.fd_array[i]); 
                            FD_CLR(fdSocket.fd_array[i], &fdSocket); 
                        } 
                    } 
                } 
            } 
        } 
        else 
        { 
            printf("nRet litter 0, error..."); 
            return; 
        } 
    } 
    ::closesocket(sListen); //与socket配对写 
    printf("*******************************"); 
    getchar(); 
}

效果如下图所示：

希望本文所述对大家的C++程序设计有所帮助。