IsMissing

Public Function IsMissing(ByVal Expression As Variant) As Boolean

Returns True if the specified variable (normally a variant parameter) if of type 'Missing'. Only variant parameters can be 'Missing'.

Public Function MyFunction(Optional pParameter As Variant)
   If IsMissing(pParameter) Then
       SendDebug "pParameter was not specified"
       ...
   Else
       ...
   End If
End Function

See also: