d
 can be called at any time
Public Sub AddMsg(uMsg As WinSubHook.eMsg)
  Dim nEntry As Long
  
  If uMsg = ALL_MESSAGES Then                             'If ALL_MESSAGES
    nMsgCnt = -1                                          'Indicates that all
     messages are to callback
  Else                                                    'Else a specific
   message number
    For nEntry = ARRAY_LB To nMsgCnt                      'For each existing
     entry. NB will skip if 0 or -1 (ALL_MESSAGES)
      Select