Module |
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Header |
/Engine/Source/Runtime/Core/Public/Misc/FieldAccessor.h |
Include |
#include "Misc/FieldAccessor.h" |
template<typename T>
class TFieldPtrAccessor
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
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TFieldPtrAccessor ( |
Self-owned value with initializer. |
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TFieldPtrAccessor ( |
Capture the value of the passed field accessor and becomes self-owned. |
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TFieldPtrAccessor |
Owned by another class that will control the value. Will not use the internal value. |
Name | Description | ||
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operator bool() |
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operator OtherT *() |
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operator T *() |
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operator!() |
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operator!= ( |
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TFieldPtrAcc... |
operator= ( |
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TFieldPtrAcc... |
operator= ( |
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TFieldPtrAcc... |
operator= ( |
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operator== ( |
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T * |
operator->() |