System.Variants.EmptyParam
Delphi
function EmptyParam: OleVariant;
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| function | public | System.Variants.pas | System.Variants | System.Variants |
Description
Contains an OleVariant that represents an unused optional parameter on a dual interface.
EmptyParam can be used for Variants that represent optional parameters whose value is unassigned. This is useful when the code that marshals method calls requires a fixed number of parameters, even if some of them are optional.
When marshaling interface calls that include optional parameters, COM requires a value for those parameters even when they are not used. EmptyParam returns an OleVariant you can pass as that value to indicate that the parameter is not used.