linux 非阻塞Tcp客户端

/**********************************************************************
* 函数名称： 建立读取H264视频TCP客户端
* 功能描述: 通过TCPClient发送"aaa"与TcpSERVER端建立连接
* 输入参数: addr　　　　TCPserver端的IP地址
　　　　　　 port　　　　TCPserver端的端口
* 输出参数: handle    建立连接后的SOCKET句柄地址
* 返 回 值：0为成功，1为失败 
* 其它说明： 
***********************************************************************/
int RecvH264Client(const char* addr, int port, int *handle )
{
    int    sockfd, recvbytes, res, flags, error, n;
    socklen_t    len;
    fd_set        rset, wset;
    struct timeval    tval;
    tval.tv_sec        = 0;
    tval.tv_usec    = 300000;
    struct sockaddr_in    serv_addr;
    char    *sendData    = "aaa";        /* 发送字符串 */
    char    buf[1024]    = {0};         /* 接收buffer */

    /* 创建socket描述符 */
    if ( (sockfd = socket( AF_INET, SOCK_STREAM, 0 ) ) == -1 )
    {
        LOGI( "socket create failed" );
        return(1);
    }

    serv_addr.sin_family        = AF_INET;
    serv_addr.sin_port        = htons( port );
    serv_addr.sin_addr.s_addr    = inet_addr( addr );
    bzero( &(serv_addr.sin_zero), 8 );
    flags = fcntl( sockfd, F_GETFL, 0 );
    fcntl( sockfd, F_SETFL, flags | O_NONBLOCK ); /* 设置为非阻塞 */

    if ( (res = connect( sockfd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr) ) ) < 0 )
    {
        if ( errno != EINPROGRESS )
        {
            return(1);
        }
    }

    /* 如果server与client在同一主机上，有些环境socket设为非阻塞会返回 0 */
    if ( 0 == res )
        goto done;
    FD_ZERO( &rset );
    FD_SET( sockfd, &rset );
    wset = rset;
    if ( (res = select( sockfd + 1, NULL, &wset, NULL, &tval ) ) <= 0 )
    {
        LOGI( "connect time out\n" );
        close( sockfd );
        return(-1);
    }else {
        len = sizeof(error);
        getsockopt( sockfd, SOL_SOCKET, SO_ERROR, &error, &len );
        if ( error )
        {
            LOGI( stderr, "Error in connection() %d - %s\n", error, strerror( error ) );
            return(1);
        }
    }

done:
    if ( (n = send( sockfd, sendData, strlen( sendData ), 0 ) ) == -1 )
    {
        LOGI( "send error!" );
        close( sockfd );
        return(1);
    }
    if ( (n = select( sockfd + 1, &rset, NULL, NULL, &tval ) ) <= 0 ) /* rset没有使用过，不用重新置为sockfd */
    {
        LOGI( "receive time out or connect error" );
        close( sockfd );
        return(1);
    }

    if ( (recvbytes = recv( sockfd, buf, 1024, 0 ) ) == -1 )
    {
        LOGI( "recv error!" );
        close( sockfd );
        return(1);
    }
    
    LOGI( "receive num %s\n", buf );

    *handle = sockfd;
    return(0);
}