TFieldPtrAccessor | Unreal Engine 5.7 Documentation

Helper to provide backward compatibility when converting a raw pointer into accessors.

The helper is trying hard to mimic's a raw pointer field functionality without breaking compatibility for existing code.

The helper's getter are all const and return a non-const pointer. This is because accessing a pointer field inside a const struct will not make that pointer const like we typically do for accessors. Since we want to mimic the behavior of a public field as much as possible, we offer that same functionality.

The helper supports being captured in a lamba as seen below and will become a const copy of the value at the capture's moment. ex: CapturedValue = Object.OnceARawFieldBecomingAnAccessor { // ExtractedValue contains a copy that will not change even if the original Object.OnceARawFieldBecomingAnAccessor changes. const Class* ExtractedValue = CapturedValue; });

This helper also supports taking a nullptr in its constructor so it properly supports conditional like such ex: ExtractedValue* Val = (Condition) ? Object.OnceARawFieldBecomingAnAccessor : nullptr;

A comforming compiler is supposed to try both conversions (nullptr -> TFieldPtrAccessor and TFieldPtrAccessor -> nullptr) but MSVC without the /permissive- flag will only try to cast nullptr into a TFieldPtrAccessor, which has to succeed to avoid breaking compabitility with existing code.

For more info, please refer to https://docs.microsoft.com/en-us/cpp/build/reference/permissive-standards-conformance?view=vs-2019#ambiguous-conditional-operator-arguments


Name	TFieldPtrAccessor
Type	class
Header File	/Engine/Source/Runtime/Core/Public/Misc/FieldAccessor.h
Include Path	#include "Misc/FieldAccessor.h"

Syntax

template<typename T>  
class TFieldPtrAccessor

Constructors

Name	Remarks	Include Path
TFieldPtrAccessor ( T* InValue )	Self-owned value with initializer.	Misc/FieldAccessor.h
TFieldPtrAccessor ( const TFieldPtrAccessor& Other )	Capture the value of the passed field accessor and becomes self-owned.	Misc/FieldAccessor.h
TFieldPtrAccessor ( TFunction< T()> InGet, TFunction< void(T)> InSet )	Owned by another class that will control the value. Will not use the internal value.	Misc/FieldAccessor.h

Variables

Protected

Name	Type	Remarks	Include Path
CapturedValue	T *	This is used only when capturing the value from another TFieldPtrAccessor.	Misc/FieldAccessor.h
Get	TFunction< T *()>		Misc/FieldAccessor.h
Set	TFunction< void(T *)>		Misc/FieldAccessor.h

Functions

Public

Operators

Name	Remarks	Include Path	Unreal Specifiers
operator bool()		Misc/FieldAccessor.h
operator OtherT *()		Misc/FieldAccessor.h
operator T*()		Misc/FieldAccessor.h
bool operator!()		Misc/FieldAccessor.h
bool operator!= ( const T* OtherPtr ) const		Misc/FieldAccessor.h
TFieldPtrAccessor & operator= ( const TFieldPtrAccessor& Other )		Misc/FieldAccessor.h
TFieldPtrAccessor & operator= ( TFieldPtrAccessor&& )		Misc/FieldAccessor.h
TFieldPtrAccessor & operator= ( T* OtherPtr )		Misc/FieldAccessor.h
bool operator== ( const T* OtherPtr ) const		Misc/FieldAccessor.h
T * operator->()		Misc/FieldAccessor.h

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