做多了windows，发现多select模式是那么的陌生，当想用心挖掘一下ACE::select的封装的时候，才发现自己几乎写不出一个完整的 select模式示例，这其实是我一直没有重视过这个东西，现在细细分析来，发现，它要比我以往在处理类似问题的时候处理的更为简单。

WSAData    wd; 
    WSAStartup(MAKEWORD(2,2),&wd); 
    SOCKET    sock    = socket(AF_INET,SOCK_STREAM,0); 
    sockaddr_in    saddr; 
    saddr.sin_family    = AF_INET; 
    saddr.sin_addr.s_addr    = inet_addr("127.0.0.1"); 
    saddr.sin_port    = htons(2350); 
    bind(sock,(SOCKADDR*)&saddr,sizeof(saddr)); 
    listen(sock,5); 
 
    SOCKET    sk2        = socket(AF_INET,SOCK_STREAM,0); 
    sockaddr_in    saddr2; 
    saddr2.sin_family    = AF_INET; 
    saddr2.sin_addr.s_addr    = inet_addr("127.0.0.1"); 
    saddr2.sin_port    = htons(2340); 
    bind(sk2,(SOCKADDR*)&saddr2,sizeof(saddr2)); 
    listen(sk2,5); 
 
    fd_set    rfd;        //read fd 
    fd_set    bkfd;        //fdbake 
    //fd_set    wfd;        //write fd 
    //fd_set    etfd;        //except fd 
    SOCKET    sac    = INVALID_SOCKET; 
    SOCKET    sac2    = INVALID_SOCKET; 
 
    FD_ZERO(&bkfd); 
    FD_SET(sock,&bkfd); 
    FD_SET(sk2,&bkfd); 
    while(true) 
    { 
        memcpy(&rfd,&bkfd,sizeof(bkfd)); 
        int    sret    = select(0,&rfd,NULL,NULL,NULL); 
        cout<<"sret:"<<sret<<endl; 
        if( ! (sret > 0) ) 
        { 
            cout<<"lasterror:"<<WSAGetLastError()<<endl; 
            //break; 
        } 
        if (FD_ISSET(sock,&rfd)) 
        { 
            closesocket(sac); 
            int    len    = sizeof(saddr); 
            sac    = accept(sock,(SOCKADDR*)&saddr,&len); 
            FD_SET(sac,&bkfd); 
        } 
        else if (FD_ISSET(sk2,&rfd)) 
        { 
            closesocket(sac2); 
            int    len    = sizeof(saddr2); 
            sac2    = accept(sk2,(SOCKADDR*)&saddr2,&len); 
            FD_SET(sac2,&bkfd); 
        } 
        else if (FD_ISSET(sac,&rfd)) 
        { 
            char    buf[1024]; 
            int    len = recv(sac,buf,1024,0); 
            if(!(len > 0)) 
            { 
                closesocket((sac)); 
                cout<<"close a socket"<<endl; 
                FD_CLR(sac,&bkfd); 
            } 
            else 
            { 
                buf[len]    = 0; 
                cout<<"recv:"<<buf<<endl; 
            } 
        } 
        else if (FD_ISSET(sac2,&rfd)) 
        { 
            char    buf[1024]; 
            int    len = recv(sac2,buf,1024,0); 
            if (len <= 0) 
            { 
                closesocket(sac2); 
                cout<<"close a socket"<<endl; 
                FD_CLR(sac,&bkfd); 
            } 
            else 
            { 
                buf[len]    = 0; 
                cout<<"recv:"<<buf<<endl; 
            } 
        } 
    } 
    WSACleanup(); 
    return 0; 

 现在我感觉到，如果想做轻量级的多sock或者异步模式，select是个不错的选择。