求助关于socket的问题

[雲哉]

int sock;
    struct sockaddr_in addr;
    fd_set rfds;
    struct timeval timeout;
    uint32 cmd;
    int rcv_val;
    uchar buf[PRB_BUF_LEN];
    int err;

    err = PRB_FAIL;

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        goto err_exit;
    }

    addr.sin_family = AF_INET;
    addr.sin_port = port;
    addr.sin_addr = ip;
    memset(addr.sin_zero, 0x00, sizeof(char));
    if (connect(sock, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 0) {
        goto normal_exit;
    }

    cmd = IO_NONBLOCKING;
    /* set mode to nonblocking */
    if (ioctl(sock, FIONBIO, (uint32)&cmd) < 0) {
        goto normal_exit;
    }

    if (send(sock, hello_msg, sizeof(hello_msg), 0) < 0) {
        goto normal_exit;
    }

    FD_ZERO(&rfds);
    FD_SET(sock, &rfds);
    timeout.tv_sec = PRB_RECV_TIMEOUT;
    timeout.tv_usec = 0;

    /* wait for data before timeout */
    if (select(sock + 1, &rfds, NULL, NULL, &timeout) <= 0) {
        goto normal_exit;
    }

    /* whether the fd set contains this socket */
    if (!FD_ISSET(sock, &rfds)) {
        goto normal_exit;
    }

    if ((rcv_val = recv(sock, buf, PRB_BUF_LEN, 0)) < 0) {
        goto normal_exit;
    }

    /* determine whether the response packet is an eMule hello response */
    if (rcv_val > 0 && buf[0] == EMU_HELLO_RSP) {
        err = PRB_OK;
    }
normal_exit:
    (void)close(sock);
err_exit:

    return err;

麻烦帮我把语句的作用解释一下，谢谢 例如设置非阻塞模式，FD_SET神马的~PPT要用

[lancerEx]

参考《unix网络编程Vol1》

[雲哉]

算了 我自己弄懂了= =、

[Gloveing]

BOOL CMyDlg::InitSocket()

{
    m_socket=WSASocket(AF_INET,SOCK_DGRAM,0,NULL,0,0);
if(INVALID_SOCKET==m_socket)
{
MessageBox("创建套接字失败!");
return FALSE;
}
SOCKADDR_IN addrSock;
addrSock.sin_addr.S_un.S_addr=htonl(ADDR_ANY);
    addrSock.sin_family=AF_INET;
addrSock.sin_port=htons(6000);

if( SOCKET_ERROR==bind(m_socket,(SOCKADDR *)&addrSock,sizeof(SOCKADDR)) )
{
MessageBox("绑定失败 !");
return FALSE;
}
if( SOCKET_ERROR== WSAAsyncSelect(m_socket,m_hWnd,UM_SOCK,FD_READ) )
{
MessageBox("注册网络消息失败!");
        return FALSE;
}
return TRUE;
}

UM_SOCK 是注册的消息，自己去写消息处理函数