System.Variants.VarIsClear
Delphi
function VarIsClear(const V: Variant): Boolean;
C++
extern DELPHI_PACKAGE bool __fastcall VarIsClear(const System::Variant &V);
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| function | public | System.Variants.pas System.Variants.hpp |
System.Variants | System.Variants |
Description
Indicates whether the specified variant has an undefined value.
VarIsClear returns true if the given variant's value is undefined. The value can be undefined for any of several reasons:
The Variant may have had its value set to Unassigned.
The Variant's value may be an interface type that has been set to nil (Delphi) or NULL (C++).
The Variant may be a custom variant that returns true from its IsClear method.
In all other cases, the function result is false.
Note: Do not confuse an unassigned variant with a Null variant. A Null variant is still assigned, but has the value Null. Unlike unassigned variants, Null variants can be used in expressions and can be converted to other types of variants.