template<
typename T>
class TFieldPtrAccessor< T >
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
1.9.8