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：

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。