typedef struct _PORT_MESSAGE32 { union { struct { short DataLength; short TotalLength; } s1; unsigned long Length; } u1; union { struct { short Type; short DataInfoOffset; } s2; unsigned long ZeroInit; } u2; union { CLIENT_ID32 ClientId; float DoNotUseThisField; }; unsigned long MessageId; union { unsigned long ClientViewSize; unsigned long CallbackId; }; } PORT_MESSAGE32, *PPORT_MESSAGE32;