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Replace union type holder to template extern variable (#62)

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Bela Schaum 2023-06-23 14:10:32 +02:00 committed by GitHub
parent f2522c2cc0
commit 8aeb677413
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1 changed files with 11 additions and 11 deletions
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22
include/nameof.hpp
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@ -968,7 +968,8 @@ constexpr auto n() noexcept {
#if defined(__clang__) || defined(__GNUC__)
constexpr auto name = pretty_name({__PRETTY_FUNCTION__, sizeof(__PRETTY_FUNCTION__) - 2});
#elif defined(_MSC_VER) && defined(_MSVC_LANG) && _MSVC_LANG >= 202002L
constexpr auto name = pretty_name({__FUNCSIG__, sizeof(__FUNCSIG__) - 17});
constexpr auto name = pretty_name({__FUNCSIG__,
sizeof(__FUNCSIG__) - 18 + std::is_member_function_pointer_v<decltype(U)>});
#else
constexpr auto name = string_view{};
#endif
@ -986,26 +987,25 @@ template <typename From, typename Type>
From get_base_type(Type From::*);
template <typename T>
union union_type {
constexpr ~union_type() {}
char c = {};
T f;
extern T nonexist_object;
template<class T>
struct Store {
T v;
};
template <typename T>
struct union_type_holder {
constexpr static union_type<T> value;
};
template<class T>
Store(T) -> Store<T>;
template <auto V>
constexpr auto get_member_name() noexcept {
consteval auto get_member_name() noexcept {
if constexpr (std::is_member_function_pointer_v<decltype(V)>) {
return n<V>();
} else {
constexpr bool is_defined = sizeof(decltype(get_base_type(V))) != 0;
static_assert(is_defined, "nameof::nameof_member member name can use only if the struct is already fully defined. Please use NAMEOF macro, or separate definition and declaration.");
if constexpr (is_defined) {
return n<V, &(union_type_holder<decltype(get_base_type(V))>::value.f.*V)>();
return n<V, Store{&(nonexist_object<decltype(get_base_type(V))>.*V)}>();
} else {
return "";
}