TVariant | Unreal Engine 5.2 Documentation

API > API/Runtime > API/Runtime/Core > API/Runtime/Core/Misc

Inheritance Hierarchy

TVariantStorage
TVariant

References


Module	Core
Header	/Engine/Source/Runtime/Core/Public/Misc/TVariant.h
Include	#include "Misc/TVariant.h"

Syntax

template<typename T, typename... Ts>  
class TVariant : private UE::Core::Private::TVariantStorage< T, Ts... >

Remarks

A type-safe union based loosely on std::variant. This flavor of variant requires that all the types in the declaring template parameter pack be unique. Attempting to use the value of a Get() when the underlying type is different leads to undefined behavior.

Constructors

	Type	Name	Description
		TVariant ()	Test for 255 here, because the parameter pack doesn't include the initial T.
		TVariant ( const TVariant& Other )	Copy construct the variant from another variant of the same type
		TVariant ( TVariant&& Other )	Move construct the variant from another variant of the same type
		TVariant ( TInPlaceType< U >&&, TArgs&&... Args )	Perform in-place construction of a type into the variant

Destructors

	Type	Name	Description
		~TVariant ()	Destruct the underlying type (if appropriate)

Functions

Type	Name	Description
void	Emplace ( TArgs&&... Args )	Set a specifically-typed value into the variant using in-place construction
U &	Get ()	Get a reference to the held value.
const U &	Get ()	Get a reference to the held value.
SIZE_T	GetIndex ()	Returns the currently held type's index into the template parameter pack
constexpr SIZE_T	IndexOfType ()	Lookup the index of a type in the template parameter pack at compile time.
bool	IsType ()	Determine if the variant holds the specific type
void	Set ( typename TIdentity< U >::Type&& Value )	Set a specifically-typed value into the variant
void	Set ( const typename TIdentity< U >::Type& Value )	Set a specifically-typed value into the variant
U *	TryGet ()	Get a pointer to the held value if the held type is the same as the one specified
const U *	TryGet ()	Get a pointer to the held value if the held type is the same as the one specified

Operators

	Type	Name	Description
	TVariant &	operator= ( TVariant&& Other )	Move assign a variant from another variant of the same type
	TVariant &	operator= ( const TVariant& Other )	Copy assign a variant from another variant of the same type

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