type
  TWMMouse = record
    Msg: TMsgParam;        ( first is the message ID )
    Keys: Word;            ( this is the wParam )
    case Integer of        ( two ways to look at the lParam )
      0: {
         XPos: Integer;    ( either as x- and y-coordinates...)
         YPos: Integer);
      1: {
         Pos: TPoint;      ( ... or as a single point )
         Result: Longint); ( and finally, the result field )
end;

struct TWMKey
{
  Cardinal Msg;                      // first parameter is the message ID
  Word CharCode;                     // this is the first wParam
  Word Unused;                       
  Longint KeyData;                   // this is the lParam
  Longint Result;                    // this is the result data member
};