typedef struct _PORT_MESSAGE
{
    union
    {
        struct
        {
            short DataLength;
            short TotalLength;
        } s1;
        unsigned long Length;
    } u1;
    union
    {
        struct
        {
            short Type;
            short DataInfoOffset;
        } s2;
        unsigned long ZeroInit;
    } u2;
    union
    {
        CLIENT_ID ClientId;
        float DoNotUseThisField;
    };
    unsigned long MessageId;
    union
    {
        unsigned __int64 ClientViewSize;
        unsigned long CallbackId;
    };
} PORT_MESSAGE, *PPORT_MESSAGE;