[libcxx-commits] [libcxx] [libc++] Deprecate `is_pod(_v)` since C++20 (PR #129471)
A. Jiang via libcxx-commits
libcxx-commits at lists.llvm.org
Wed Mar 5 18:53:33 PST 2025
https://github.com/frederick-vs-ja updated https://github.com/llvm/llvm-project/pull/129471
>From 919fa850fe280618b66d24e1f3604b66fa5adbdd Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Mon, 3 Mar 2025 11:34:59 +0800
Subject: [PATCH 1/3] [libc++] Deprecate `is_pod(_v)` since C++20
Previously, commit 042f07eed8c1acba19ea04310137bee12b18045a claimed that
P0767R1 was implemented in LLVM 7.0, but no deprecation warning was
implemented. This patch adds the missing warnings.
---
libcxx/docs/ReleaseNotes/21.rst | 2 ++
libcxx/include/__type_traits/is_pod.h | 5 +++--
libcxx/include/type_traits | 4 ++--
.../is_pod.deprecated.verify.cpp | 18 ++++++++++++++++++
.../meta.unary/meta.unary.prop/is_pod.pass.cpp | 2 ++
5 files changed, 27 insertions(+), 4 deletions(-)
create mode 100644 libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.deprecated.verify.cpp
diff --git a/libcxx/docs/ReleaseNotes/21.rst b/libcxx/docs/ReleaseNotes/21.rst
index e7cfa625a132c..a8d15a0f2f898 100644
--- a/libcxx/docs/ReleaseNotes/21.rst
+++ b/libcxx/docs/ReleaseNotes/21.rst
@@ -55,6 +55,8 @@ Improvements and New Features
Deprecations and Removals
-------------------------
+- ``std::is_pod`` and ``std::is_pod_v`` are deprecated since C++20 according to the standard.
+
Upcoming Deprecations and Removals
----------------------------------
diff --git a/libcxx/include/__type_traits/is_pod.h b/libcxx/include/__type_traits/is_pod.h
index a57662400394a..b6aacf3b2b202 100644
--- a/libcxx/include/__type_traits/is_pod.h
+++ b/libcxx/include/__type_traits/is_pod.h
@@ -19,11 +19,12 @@
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_pod : public integral_constant<bool, __is_pod(_Tp)> {};
+struct _LIBCPP_TEMPLATE_VIS
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_NO_SPECIALIZATIONS is_pod : public integral_constant<bool, __is_pod(_Tp)> {};
#if _LIBCPP_STD_VER >= 17
template <class _Tp>
-_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_pod_v = __is_pod(_Tp);
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_pod_v = __is_pod(_Tp);
#endif
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
index ffcddb0176615..772e4cb876469 100644
--- a/libcxx/include/type_traits
+++ b/libcxx/include/type_traits
@@ -95,8 +95,8 @@ namespace std
template <class T> struct is_unbounded_array; // C++20
// Member introspection:
- template <class T> struct is_pod;
template <class T> struct is_trivial;
+ template <class T> struct is_pod; // Deprecated in C++20
template <class T> struct is_trivially_copyable;
template <class T> struct is_standard_layout;
template <class T> struct is_literal_type; // Deprecated in C++17; removed in C++20
@@ -303,7 +303,7 @@ namespace std
template <class T> inline constexpr bool is_standard_layout_v
= is_standard_layout<T>::value; // C++17
template <class T> inline constexpr bool is_pod_v
- = is_pod<T>::value; // C++17
+ = is_pod<T>::value; // C++17; deprecated in C++20
template <class T> inline constexpr bool is_literal_type_v
= is_literal_type<T>::value; // C++17; deprecated in C++17; removed in C++20
template <class T> inline constexpr bool is_empty_v
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.deprecated.verify.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.deprecated.verify.cpp
new file mode 100644
index 0000000000000..0f9b1856591d8
--- /dev/null
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.deprecated.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: std-at-least-c++20
+
+// <type_traits>
+
+// is_pod and is_pod_v are deprecated in C++20 by P0767R1
+
+#include <type_traits>
+
+static_assert(std::is_pod<int>::value); // expected-warning {{'is_pod<int>' is deprecated}}
+static_assert(std::is_pod_v<int>); // expected-warning {{'is_pod_v<int>' is deprecated}}
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
index 87fe6ebbee883..887033fc72d86 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
@@ -10,6 +10,8 @@
// is_pod
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
#include <type_traits>
#include "test_macros.h"
>From 62485b536b326b6df2e5069227954e7d0d2587f8 Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Tue, 4 Mar 2025 17:09:29 +0800
Subject: [PATCH 2/3] Modify release notes and the status page per review
comments.
---
libcxx/docs/ReleaseNotes/21.rst | 3 ++-
libcxx/docs/Status/Cxx20Papers.csv | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/libcxx/docs/ReleaseNotes/21.rst b/libcxx/docs/ReleaseNotes/21.rst
index a8d15a0f2f898..dd9b683af0901 100644
--- a/libcxx/docs/ReleaseNotes/21.rst
+++ b/libcxx/docs/ReleaseNotes/21.rst
@@ -39,6 +39,7 @@ Implemented Papers
------------------
- N4258: Cleaning-up noexcept in the Library (`Github <https://github.com/llvm/llvm-project/issues/99937>`__)
+- P0767R1: Deprecate POD (`Github <https://github.com/llvm/llvm-project/issues/104013>`__)
- P1361R2: Integration of chrono with text formatting (`Github <https://github.com/llvm/llvm-project/issues/100014>`__)
Improvements and New Features
@@ -55,7 +56,7 @@ Improvements and New Features
Deprecations and Removals
-------------------------
-- ``std::is_pod`` and ``std::is_pod_v`` are deprecated since C++20 according to the standard.
+- ``std::is_pod`` and ``std::is_pod_v`` are deprecated in C++20 and later.
Upcoming Deprecations and Removals
----------------------------------
diff --git a/libcxx/docs/Status/Cxx20Papers.csv b/libcxx/docs/Status/Cxx20Papers.csv
index cb25006797055..4430b785334c1 100644
--- a/libcxx/docs/Status/Cxx20Papers.csv
+++ b/libcxx/docs/Status/Cxx20Papers.csv
@@ -13,7 +13,7 @@
"`P0616R0 <https://wg21.link/P0616R0>`__","de-pessimize legacy <numeric> algorithms with std::move","2017-11 (Albuquerque)","|Complete|","12",""
"`P0653R2 <https://wg21.link/P0653R2>`__","Utility to convert a pointer to a raw pointer","2017-11 (Albuquerque)","|Complete|","6",""
"`P0718R2 <https://wg21.link/P0718R2>`__","Atomic shared_ptr","2017-11 (Albuquerque)","","",""
-"`P0767R1 <https://wg21.link/P0767R1>`__","Deprecate POD","2017-11 (Albuquerque)","|Complete|","7",""
+"`P0767R1 <https://wg21.link/P0767R1>`__","Deprecate POD","2017-11 (Albuquerque)","|Complete|","21","It was previously erroneously marked as complete in LLVM 7."
"`P0768R1 <https://wg21.link/P0768R1>`__","Library Support for the Spaceship (Comparison) Operator","2017-11 (Albuquerque)","|Complete|","",""
"`P0777R1 <https://wg21.link/P0777R1>`__","Treating Unnecessary ``decay``\ ","2017-11 (Albuquerque)","|Complete|","7",""
"","","","","",""
>From 372e8a98990879ceb85e72c9972434ffa83a4a24 Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Thu, 6 Mar 2025 10:51:13 +0800
Subject: [PATCH 3/3] Drive-by changes in `<type_traits>`
- aligning all version comments to line 65,
- using `// since C++` instead of `// C++`, in lowercase as used in most version comments,
- changing the comments for `bool_constant` to `// since C++17` as it's a C++17 feature,
- changing the class-key of `result_of` to `struct`, which follows N4659 [depr.meta.types] and the actual usage in libc++,
- consistently using `class` to introduce type template parameters,
- consistently using `inline constexpr` for variable templates,
- moving the comments for `is_nothrow_convertible_v` to the part for variable templates, and
- removing duplicated comments for `true_type` and `false_type`.
---
libcxx/include/type_traits | 313 ++++++++++++++++++++-----------------
1 file changed, 166 insertions(+), 147 deletions(-)
diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
index 772e4cb876469..88ebdc3e1a784 100644
--- a/libcxx/include/type_traits
+++ b/libcxx/include/type_traits
@@ -18,13 +18,11 @@ namespace std
// helper class:
template <class T, T v> struct integral_constant;
- typedef integral_constant<bool, true> true_type; // C++11
- typedef integral_constant<bool, false> false_type; // C++11
+ typedef integral_constant<bool, true> true_type; // since C++11
+ typedef integral_constant<bool, false> false_type; // since C++11
- template <bool B> // C++14
- using bool_constant = integral_constant<bool, B>; // C++14
- typedef bool_constant<true> true_type; // C++14
- typedef bool_constant<false> false_type; // C++14
+ template <bool B>
+ using bool_constant = integral_constant<bool, B>; // since C++17
// helper traits
template <bool, class T = void> struct enable_if;
@@ -32,7 +30,7 @@ namespace std
// Primary classification traits:
template <class T> struct is_void;
- template <class T> struct is_null_pointer; // C++14
+ template <class T> struct is_null_pointer; // since C++14
template <class T> struct is_integral;
template <class T> struct is_floating_point;
template <class T> struct is_array;
@@ -51,7 +49,7 @@ namespace std
template <class T> struct is_arithmetic;
template <class T> struct is_fundamental;
template <class T> struct is_member_pointer;
- template <class T> struct is_scoped_enum; // C++23
+ template <class T> struct is_scoped_enum; // since C++23
template <class T> struct is_scalar;
template <class T> struct is_object;
template <class T> struct is_compound;
@@ -75,9 +73,9 @@ namespace std
template <class T> struct remove_pointer;
template <class T> struct add_pointer;
- template<class T> struct type_identity; // C++20
+ template<class T> struct type_identity; // since C++20
template<class T>
- using type_identity_t = typename type_identity<T>::type; // C++20
+ using type_identity_t = typename type_identity<T>::type; // since C++20
// Integral properties:
template <class T> struct is_signed;
@@ -91,20 +89,20 @@ namespace std
template <class T> struct remove_extent;
template <class T> struct remove_all_extents;
- template <class T> struct is_bounded_array; // C++20
- template <class T> struct is_unbounded_array; // C++20
+ template <class T> struct is_bounded_array; // since C++20
+ template <class T> struct is_unbounded_array; // since C++20
// Member introspection:
template <class T> struct is_trivial;
- template <class T> struct is_pod; // Deprecated in C++20
+ template <class T> struct is_pod; // deprecated in C++20
template <class T> struct is_trivially_copyable;
template <class T> struct is_standard_layout;
- template <class T> struct is_literal_type; // Deprecated in C++17; removed in C++20
+ template <class T> struct is_literal_type; // deprecated in C++17; removed in C++20
template <class T> struct is_empty;
template <class T> struct is_polymorphic;
template <class T> struct is_abstract;
- template <class T> struct is_final; // C++14
- template <class T> struct is_aggregate; // C++17
+ template <class T> struct is_final; // since C++14
+ template <class T> struct is_aggregate; // since C++17
template <class T, class... Args> struct is_constructible;
template <class T> struct is_default_constructible;
@@ -113,8 +111,8 @@ namespace std
template <class T, class U> struct is_assignable;
template <class T> struct is_copy_assignable;
template <class T> struct is_move_assignable;
- template <class T, class U> struct is_swappable_with; // C++17
- template <class T> struct is_swappable; // C++17
+ template <class T, class U> struct is_swappable_with; // since C++17
+ template <class T> struct is_swappable; // since C++17
template <class T> struct is_destructible;
template <class T, class... Args> struct is_trivially_constructible;
@@ -133,24 +131,27 @@ namespace std
template <class T, class U> struct is_nothrow_assignable;
template <class T> struct is_nothrow_copy_assignable;
template <class T> struct is_nothrow_move_assignable;
- template <class T, class U> struct is_nothrow_swappable_with; // C++17
- template <class T> struct is_nothrow_swappable; // C++17
+ template <class T, class U>
+ struct is_nothrow_swappable_with; // since C++17
+ template <class T>
+ struct is_nothrow_swappable; // since C++17
template <class T> struct is_nothrow_destructible;
- template<class T> struct is_implicit_lifetime; // Since C++23
+ template<class T> struct is_implicit_lifetime; // since C++23
template <class T> struct has_virtual_destructor;
- template<class T> struct has_unique_object_representations; // C++17
+ template<class T> struct has_unique_object_representations; // since C++17
// Relationships between types:
template <class T, class U> struct is_same;
template <class Base, class Derived> struct is_base_of;
- template <class Base, class Derived> struct is_virtual_base_of; // C++26
+ template <class Base, class Derived>
+ struct is_virtual_base_of; // since C++26
template <class From, class To> struct is_convertible;
- template <typename From, typename To> struct is_nothrow_convertible; // C++20
- template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
+ template <class From, class To>
+ struct is_nothrow_convertible; // since C++20
template <class Fn, class... ArgTypes> struct is_invocable;
template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
@@ -161,264 +162,282 @@ namespace std
// Alignment properties and transformations:
template <class T> struct alignment_of;
template <size_t Len, size_t Align = most_stringent_alignment_requirement>
- struct aligned_storage; // deprecated in C++23
+ struct aligned_storage; // deprecated in C++23
template <size_t Len, class... Types> struct aligned_union; // deprecated in C++23
- template <class T> struct remove_cvref; // C++20
+ template <class T> struct remove_cvref; // since C++20
template <class T> struct decay;
template <class... T> struct common_type;
template <class T> struct underlying_type;
- template <class> class result_of; // undefined; deprecated in C++17; removed in C++20
- template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
- template <class Fn, class... ArgTypes> struct invoke_result; // C++17
+ template <class> struct result_of; // undefined; deprecated in C++17; removed in C++20
+ template <class Fn, class... ArgTypes>
+ struct result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
+ template <class Fn, class... ArgTypes>
+ struct invoke_result; // since C++17
// const-volatile modifications:
template <class T>
- using remove_const_t = typename remove_const<T>::type; // C++14
+ using remove_const_t = typename remove_const<T>::type; // since C++14
template <class T>
- using remove_volatile_t = typename remove_volatile<T>::type; // C++14
+ using remove_volatile_t
+ = typename remove_volatile<T>::type; // since C++14
template <class T>
- using remove_cv_t = typename remove_cv<T>::type; // C++14
+ using remove_cv_t = typename remove_cv<T>::type; // since C++14
template <class T>
- using add_const_t = typename add_const<T>::type; // C++14
+ using add_const_t = typename add_const<T>::type; // since C++14
template <class T>
- using add_volatile_t = typename add_volatile<T>::type; // C++14
+ using add_volatile_t = typename add_volatile<T>::type; // since C++14
template <class T>
- using add_cv_t = typename add_cv<T>::type; // C++14
+ using add_cv_t = typename add_cv<T>::type; // since C++14
// reference modifications:
template <class T>
- using remove_reference_t = typename remove_reference<T>::type; // C++14
+ using remove_reference_t
+ = typename remove_reference<T>::type; // since C++14
template <class T>
- using add_lvalue_reference_t = typename add_lvalue_reference<T>::type; // C++14
+ using add_lvalue_reference_t
+ = typename add_lvalue_reference<T>::type; // since C++14
template <class T>
- using add_rvalue_reference_t = typename add_rvalue_reference<T>::type; // C++14
+ using add_rvalue_reference_t
+ = typename add_rvalue_reference<T>::type; // since C++14
// sign modifications:
template <class T>
- using make_signed_t = typename make_signed<T>::type; // C++14
+ using make_signed_t = typename make_signed<T>::type; // since C++14
template <class T>
- using make_unsigned_t = typename make_unsigned<T>::type; // C++14
+ using make_unsigned_t = typename make_unsigned<T>::type; // since C++14
// array modifications:
template <class T>
- using remove_extent_t = typename remove_extent<T>::type; // C++14
+ using remove_extent_t
+ = typename remove_extent<T>::type; // since C++14
template <class T>
- using remove_all_extents_t = typename remove_all_extents<T>::type; // C++14
+ using remove_all_extents_t
+ = typename remove_all_extents<T>::type; // since C++14
template <class T>
inline constexpr bool is_bounded_array_v
- = is_bounded_array<T>::value; // C++20
+ = is_bounded_array<T>::value; // since C++20
inline constexpr bool is_unbounded_array_v
- = is_unbounded_array<T>::value; // C++20
+ = is_unbounded_array<T>::value; // since C++20
// pointer modifications:
template <class T>
- using remove_pointer_t = typename remove_pointer<T>::type; // C++14
+ using remove_pointer_t
+ = typename remove_pointer<T>::type; // since C++14
template <class T>
- using add_pointer_t = typename add_pointer<T>::type; // C++14
+ using add_pointer_t = typename add_pointer<T>::type; // since C++14
// other transformations:
template <size_t Len, size_t Align=default-alignment>
- using aligned_storage_t = typename aligned_storage<Len,Align>::type; // C++14
+ using aligned_storage_t
+ = typename aligned_storage<Len,Align>::type; // since C++14
template <size_t Len, class... Types>
- using aligned_union_t = typename aligned_union<Len,Types...>::type; // C++14
+ using aligned_union_t
+ = typename aligned_union<Len,Types...>::type; // since C++14
template <class T>
- using remove_cvref_t = typename remove_cvref<T>::type; // C++20
+ using remove_cvref_t
+ = typename remove_cvref<T>::type; // since C++20
template <class T>
- using decay_t = typename decay<T>::type; // C++14
+ using decay_t = typename decay<T>::type; // since C++14
template <bool b, class T=void>
- using enable_if_t = typename enable_if<b,T>::type; // C++14
+ using enable_if_t = typename enable_if<b,T>::type; // since C++14
template <bool b, class T, class F>
- using conditional_t = typename conditional<b,T,F>::type; // C++14
+ using conditional_t
+ = typename conditional<b,T,F>::type; // since C++14
template <class... T>
- using common_type_t = typename common_type<T...>::type; // C++14
+ using common_type_t
+ = typename common_type<T...>::type; // since C++14
template <class T>
- using underlying_type_t = typename underlying_type<T>::type; // C++14
+ using underlying_type_t
+ = typename underlying_type<T>::type; // since C++14
template <class T>
- using result_of_t = typename result_of<T>::type; // C++14; deprecated in C++17; removed in C++20
+ using result_of_t = typename result_of<T>::type; // since C++14; deprecated in C++17; removed in C++20
template <class Fn, class... ArgTypes>
- using invoke_result_t = typename invoke_result<Fn, ArgTypes...>::type; // C++17
+ using invoke_result_t
+ = typename invoke_result<Fn, ArgTypes...>::type; // since C++17
template <class...>
- using void_t = void; // C++17
+ using void_t = void; // since C++17
// See C++14 20.10.4.1, primary type categories
template <class T> inline constexpr bool is_void_v
- = is_void<T>::value; // C++17
+ = is_void<T>::value; // since C++17
template <class T> inline constexpr bool is_null_pointer_v
- = is_null_pointer<T>::value; // C++17
+ = is_null_pointer<T>::value; // since C++17
template <class T> inline constexpr bool is_integral_v
- = is_integral<T>::value; // C++17
+ = is_integral<T>::value; // since C++17
template <class T> inline constexpr bool is_floating_point_v
- = is_floating_point<T>::value; // C++17
+ = is_floating_point<T>::value; // since C++17
template <class T> inline constexpr bool is_array_v
- = is_array<T>::value; // C++17
+ = is_array<T>::value; // since C++17
template <class T> inline constexpr bool is_pointer_v
- = is_pointer<T>::value; // C++17
+ = is_pointer<T>::value; // since C++17
template <class T> inline constexpr bool is_lvalue_reference_v
- = is_lvalue_reference<T>::value; // C++17
+ = is_lvalue_reference<T>::value; // since C++17
template <class T> inline constexpr bool is_rvalue_reference_v
- = is_rvalue_reference<T>::value; // C++17
+ = is_rvalue_reference<T>::value; // since C++17
template <class T> inline constexpr bool is_member_object_pointer_v
- = is_member_object_pointer<T>::value; // C++17
+ = is_member_object_pointer<T>::value; // since C++17
template <class T> inline constexpr bool is_member_function_pointer_v
- = is_member_function_pointer<T>::value; // C++17
+ = is_member_function_pointer<T>::value; // since C++17
template <class T> inline constexpr bool is_enum_v
- = is_enum<T>::value; // C++17
+ = is_enum<T>::value; // since C++17
template <class T> inline constexpr bool is_union_v
- = is_union<T>::value; // C++17
+ = is_union<T>::value; // since C++17
template <class T> inline constexpr bool is_class_v
- = is_class<T>::value; // C++17
+ = is_class<T>::value; // since C++17
template <class T> inline constexpr bool is_function_v
- = is_function<T>::value; // C++17
+ = is_function<T>::value; // since C++17
// See C++14 20.10.4.2, composite type categories
template <class T> inline constexpr bool is_reference_v
- = is_reference<T>::value; // C++17
+ = is_reference<T>::value; // since C++17
template <class T> inline constexpr bool is_arithmetic_v
- = is_arithmetic<T>::value; // C++17
+ = is_arithmetic<T>::value; // since C++17
template <class T> inline constexpr bool is_fundamental_v
- = is_fundamental<T>::value; // C++17
+ = is_fundamental<T>::value; // since C++17
template <class T> inline constexpr bool is_object_v
- = is_object<T>::value; // C++17
+ = is_object<T>::value; // since C++17
template <class T> inline constexpr bool is_scalar_v
- = is_scalar<T>::value; // C++17
+ = is_scalar<T>::value; // since C++17
template <class T> inline constexpr bool is_compound_v
- = is_compound<T>::value; // C++17
+ = is_compound<T>::value; // since C++17
template <class T> inline constexpr bool is_member_pointer_v
- = is_member_pointer<T>::value; // C++17
+ = is_member_pointer<T>::value; // since C++17
template <class T> inline constexpr bool is_scoped_enum_v
- = is_scoped_enum<T>::value; // C++23
+ = is_scoped_enum<T>::value; // since C++23
// See C++14 20.10.4.3, type properties
template <class T> inline constexpr bool is_const_v
- = is_const<T>::value; // C++17
+ = is_const<T>::value; // since C++17
template <class T> inline constexpr bool is_volatile_v
- = is_volatile<T>::value; // C++17
+ = is_volatile<T>::value; // since C++17
template <class T> inline constexpr bool is_trivial_v
- = is_trivial<T>::value; // C++17
+ = is_trivial<T>::value; // since C++17
template <class T> inline constexpr bool is_trivially_copyable_v
- = is_trivially_copyable<T>::value; // C++17
+ = is_trivially_copyable<T>::value; // since C++17
template <class T> inline constexpr bool is_standard_layout_v
- = is_standard_layout<T>::value; // C++17
+ = is_standard_layout<T>::value; // since C++17
template <class T> inline constexpr bool is_pod_v
- = is_pod<T>::value; // C++17; deprecated in C++20
+ = is_pod<T>::value; // since C++17; deprecated in C++20
template <class T> inline constexpr bool is_literal_type_v
- = is_literal_type<T>::value; // C++17; deprecated in C++17; removed in C++20
+ = is_literal_type<T>::value; // since C++17; deprecated in C++17; removed in C++20
template <class T> inline constexpr bool is_empty_v
- = is_empty<T>::value; // C++17
+ = is_empty<T>::value; // since C++17
template <class T> inline constexpr bool is_polymorphic_v
- = is_polymorphic<T>::value; // C++17
+ = is_polymorphic<T>::value; // since C++17
template <class T> inline constexpr bool is_abstract_v
- = is_abstract<T>::value; // C++17
+ = is_abstract<T>::value; // since C++17
template <class T> inline constexpr bool is_final_v
- = is_final<T>::value; // C++17
+ = is_final<T>::value; // since C++17
template <class T> inline constexpr bool is_aggregate_v
- = is_aggregate<T>::value; // C++17
+ = is_aggregate<T>::value; // since C++17
template <class T> inline constexpr bool is_signed_v
- = is_signed<T>::value; // C++17
+ = is_signed<T>::value; // since C++17
template <class T> inline constexpr bool is_unsigned_v
- = is_unsigned<T>::value; // C++17
+ = is_unsigned<T>::value; // since C++17
template <class T, class... Args> inline constexpr bool is_constructible_v
- = is_constructible<T, Args...>::value; // C++17
+ = is_constructible<T, Args...>::value; // since C++17
template <class T> inline constexpr bool is_default_constructible_v
- = is_default_constructible<T>::value; // C++17
+ = is_default_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_copy_constructible_v
- = is_copy_constructible<T>::value; // C++17
+ = is_copy_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_move_constructible_v
- = is_move_constructible<T>::value; // C++17
+ = is_move_constructible<T>::value; // since C++17
template <class T, class U> inline constexpr bool is_assignable_v
- = is_assignable<T, U>::value; // C++17
+ = is_assignable<T, U>::value; // since C++17
template <class T> inline constexpr bool is_copy_assignable_v
- = is_copy_assignable<T>::value; // C++17
+ = is_copy_assignable<T>::value; // since C++17
template <class T> inline constexpr bool is_move_assignable_v
- = is_move_assignable<T>::value; // C++17
+ = is_move_assignable<T>::value; // since C++17
template <class T, class U> inline constexpr bool is_swappable_with_v
- = is_swappable_with<T, U>::value; // C++17
+ = is_swappable_with<T, U>::value; // since C++17
template <class T> inline constexpr bool is_swappable_v
- = is_swappable<T>::value; // C++17
+ = is_swappable<T>::value; // since C++17
template <class T> inline constexpr bool is_destructible_v
- = is_destructible<T>::value; // C++17
+ = is_destructible<T>::value; // since C++17
template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
- = is_trivially_constructible<T, Args...>::value; // C++17
+ = is_trivially_constructible<T, Args...>::value; // since C++17
template <class T> inline constexpr bool is_trivially_default_constructible_v
- = is_trivially_default_constructible<T>::value; // C++17
+ = is_trivially_default_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_trivially_copy_constructible_v
- = is_trivially_copy_constructible<T>::value; // C++17
+ = is_trivially_copy_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_trivially_move_constructible_v
- = is_trivially_move_constructible<T>::value; // C++17
+ = is_trivially_move_constructible<T>::value; // since C++17
template <class T, class U> inline constexpr bool is_trivially_assignable_v
- = is_trivially_assignable<T, U>::value; // C++17
+ = is_trivially_assignable<T, U>::value; // since C++17
template <class T> inline constexpr bool is_trivially_copy_assignable_v
- = is_trivially_copy_assignable<T>::value; // C++17
+ = is_trivially_copy_assignable<T>::value; // since C++17
template <class T> inline constexpr bool is_trivially_move_assignable_v
- = is_trivially_move_assignable<T>::value; // C++17
+ = is_trivially_move_assignable<T>::value; // since C++17
template <class T> inline constexpr bool is_trivially_destructible_v
- = is_trivially_destructible<T>::value; // C++17
+ = is_trivially_destructible<T>::value; // since C++17
template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
- = is_nothrow_constructible<T, Args...>::value; // C++17
+ = is_nothrow_constructible<T, Args...>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_default_constructible_v
- = is_nothrow_default_constructible<T>::value; // C++17
+ = is_nothrow_default_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_copy_constructible_v
- = is_nothrow_copy_constructible<T>::value; // C++17
+ = is_nothrow_copy_constructible<T>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_move_constructible_v
- = is_nothrow_move_constructible<T>::value; // C++17
+ = is_nothrow_move_constructible<T>::value; // since C++17
template <class T, class U> inline constexpr bool is_nothrow_assignable_v
- = is_nothrow_assignable<T, U>::value; // C++17
+ = is_nothrow_assignable<T, U>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_copy_assignable_v
- = is_nothrow_copy_assignable<T>::value; // C++17
+ = is_nothrow_copy_assignable<T>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_move_assignable_v
- = is_nothrow_move_assignable<T>::value; // C++17
+ = is_nothrow_move_assignable<T>::value; // since C++17
template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
- = is_nothrow_swappable_with<T, U>::value; // C++17
+ = is_nothrow_swappable_with<T, U>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_swappable_v
- = is_nothrow_swappable<T>::value; // C++17
+ = is_nothrow_swappable<T>::value; // since C++17
template <class T> inline constexpr bool is_nothrow_destructible_v
- = is_nothrow_destructible<T>::value; // C++17
- template<class T>
- constexpr bool is_implicit_lifetime_v = is_implicit_lifetime<T>::value; // Since C++23
+ = is_nothrow_destructible<T>::value; // since C++17
+ template <class T> inline constexpr bool is_implicit_lifetime_v
+ = is_implicit_lifetime<T>::value; // since C++23
template <class T> inline constexpr bool has_virtual_destructor_v
- = has_virtual_destructor<T>::value; // C++17
- template<class T> inline constexpr bool has_unique_object_representations_v // C++17
- = has_unique_object_representations<T>::value;
+ = has_virtual_destructor<T>::value; // since C++17
+ template<class T> inline constexpr bool has_unique_object_representations_v
+ = has_unique_object_representations<T>::value; // since C++17
// See C++14 20.10.5, type property queries
template <class T> inline constexpr size_t alignment_of_v
- = alignment_of<T>::value; // C++17
+ = alignment_of<T>::value; // since C++17
template <class T> inline constexpr size_t rank_v
- = rank<T>::value; // C++17
+ = rank<T>::value; // since C++17
template <class T, unsigned I = 0> inline constexpr size_t extent_v
- = extent<T, I>::value; // C++17
+ = extent<T, I>::value; // since C++17
// See C++14 20.10.6, type relations
template <class T, class U> inline constexpr bool is_same_v
- = is_same<T, U>::value; // C++17
+ = is_same<T, U>::value; // since C++17
template <class Base, class Derived> inline constexpr bool is_base_of_v
- = is_base_of<Base, Derived>::value; // C++17
+ = is_base_of<Base, Derived>::value; // since C++17
template <class Base, class Derived> inline constexpr bool is_virtual_base_of_v
- = is_virtual_base_of<Base, Derived>::value; // C++26
+ = is_virtual_base_of<Base, Derived>::value; // since C++26
template <class From, class To> inline constexpr bool is_convertible_v
- = is_convertible<From, To>::value; // C++17
+ = is_convertible<From, To>::value; // since C++17
+ template <class From, class To> inline constexpr bool is_nothrow_convertible_v
+ = is_nothrow_convertible<From, To>::value; // since C++20
template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
- = is_invocable<Fn, ArgTypes...>::value; // C++17
+ = is_invocable<Fn, ArgTypes...>::value; // since C++17
template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
- = is_invocable_r<R, Fn, ArgTypes...>::value; // C++17
+ = is_invocable_r<R, Fn, ArgTypes...>::value; // since C++17
template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
- = is_nothrow_invocable<Fn, ArgTypes...>::value; // C++17
+ = is_nothrow_invocable<Fn, ArgTypes...>::value; // since C++17
template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
- = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value; // C++17
+ = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value; // since C++17
// [meta.logical], logical operator traits:
- template<class... B> struct conjunction; // C++17
- template<class... B>
- inline constexpr bool conjunction_v = conjunction<B...>::value; // C++17
- template<class... B> struct disjunction; // C++17
- template<class... B>
- inline constexpr bool disjunction_v = disjunction<B...>::value; // C++17
- template<class B> struct negation; // C++17
- template<class B>
- inline constexpr bool negation_v = negation<B>::value; // C++17
+ template<class... B> struct conjunction; // since C++17
+ template<class... B> inline constexpr bool conjunction_v
+ = conjunction<B...>::value; // since C++17
+ template<class... B> struct disjunction; // since C++17
+ template<class... B> inline constexpr bool disjunction_v
+ = disjunction<B...>::value; // since C++17
+ template<class B> struct negation; // since C++17
+ template<class B> inline constexpr bool negation_v
+ = negation<B>::value; // since C++17
}
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