diff options
Diffstat (limited to 'absl/meta')
| -rw-r--r-- | absl/meta/type_traits.h | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/absl/meta/type_traits.h b/absl/meta/type_traits.h index ced66269b063..6f7138c2d8db 100644 --- a/absl/meta/type_traits.h +++ b/absl/meta/type_traits.h @@ -135,8 +135,11 @@ struct negation : std::integral_constant<bool, !T::value> {}; // // Determines whether the passed type `T` is trivially destructable. // -// This metafunction is designed to be a drop-in replacement for the C++17 -// `std::is_trivially_destructible()` metafunction. +// This metafunction is designed to be a drop-in replacement for the C++11 +// `std::is_trivially_destructible()` metafunction for platforms that have +// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do +// fully support C++11, we check whether this yields the same result as the std +// implementation. // // NOTE: the extensions (__has_trivial_xxx) are implemented in gcc (version >= // 4.3) and clang. Since we are supporting libstdc++ > 4.7, they should always @@ -157,8 +160,11 @@ struct is_trivially_destructible // // Determines whether the passed type `T` is trivially default constructible. // -// This metafunction is designed to be a drop-in replacement for the C++17 -// `std::is_trivially_default_constructible()` metafunction. +// This metafunction is designed to be a drop-in replacement for the C++11 +// `std::is_trivially_default_constructible()` metafunction for platforms that +// have incomplete C++11 support (such as libstdc++ 4.x). On any platforms that +// do fully support C++11, we check whether this yields the same result as the +// std implementation. // // NOTE: according to the C++ standard, Section: 20.15.4.3 [meta.unary.prop] // "The predicate condition for a template specialization is_constructible<T, @@ -199,8 +205,11 @@ struct is_trivially_default_constructible // // Determines whether the passed type `T` is trivially copy constructible. // -// This metafunction is designed to be a drop-in replacement for the C++17 -// `std::is_trivially_copy_constructible()` metafunction. +// This metafunction is designed to be a drop-in replacement for the C++11 +// `std::is_trivially_copy_constructible()` metafunction for platforms that have +// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do +// fully support C++11, we check whether this yields the same result as the std +// implementation. // // NOTE: `T obj(declval<const T&>());` needs to be well-formed and not call any // nontrivial operation. Nontrivally destructible types will cause the @@ -221,8 +230,11 @@ struct is_trivially_copy_constructible // // Determines whether the passed type `T` is trivially copy assignable. // -// This metafunction is designed to be a drop-in replacement for the C++17 -// `std::is_trivially_copy_assignable()` metafunction. +// This metafunction is designed to be a drop-in replacement for the C++11 +// `std::is_trivially_copy_assignable()` metafunction for platforms that have +// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do +// fully support C++11, we check whether this yields the same result as the std +// implementation. // // NOTE: `is_assignable<T, U>::value` is `true` if the expression // `declval<T>() = declval<U>()` is well-formed when treated as an unevaluated |