System.Variants.Unassigned

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Delphi

function Unassigned: Variant;

C++

extern DELPHI_PACKAGE System::Variant __fastcall Unassigned(void);

Properties

Type	Visibility	Source	Unit	Parent
function	public	System.Variants.pas System.Variants.hpp	System.Variants	System.Variants

Description

Returns an "empty" variant.

A variant variable can be "empty", meaning it has not yet been assigned to. The Unassigned function returns an empty variant, which can be assigned to a variant variable to restore the variable to its initial state.

Use the VarIsEmpty function to test whether a variant is empty. When used on an empty variant, the VarType standard function returns varEmpty.

If an empty variant is cast to another type (for example, by assigning to a non-variant variable or calling VarAsType) the following conversions occur:

Destination	Conversion result
Numeric type	Zero
String type	Empty string
Boolean	False.

Note: Unassigned is useful with variants referencing OLE Automation Objects that you want to keep "alive" until another value is assigned to the variant.

There's corresponding functionality under Linux. Should document when time permits.

See Also

• Null

• VarIsEmpty

• VarType

• VarAsType

• Variant Support Routines