MPARAM

MPARAM

A 4-byte message-dependent parameter structure.

Type

void

C Declaration Method

typedef

Comment

Certain elements of information, placed into the parameters of a message, have
data types that do not use all four bytes of this data type. The rules
governing these cases are: 

BOOL   The value is contained in the low word and the high word is 0.
SHORT  The value is contained in the low word and its sign is extended into the high word.
USHORT The value is contained in the low word and the high word is 0. 
NULL   The entire four bytes are 0. 
 
The structure of this data type depends on the message. For details, see the
description of the particular message.