[Note: many of the tests for the original versions do not make
sense, require different outcomes, or otherwise fail on the new
versions for reasons not obvious.]
Add non-type template parameter function-object/-pointer argument
versions of bind_front, bind_back, and not_fn as defined in P2714R1.
libstdc++-v3/ChangeLog:
PR libstdc++/119744
* include/bits/version.def: Redefine __cpp_lib_bind_front etc.
* include/bits/version.h: Ditto.
* include/std/functional: Add new bind_front etc. overloads
* testsuite/20_util/function_objects/bind_back/1.cc
* testsuite/20_util/function_objects/bind_back/nttp.cc
* testsuite/20_util/function_objects/bind_front/1.cc
* testsuite/20_util/function_objects/bind_front/nttp.cc
* testsuite/20_util/function_objects/not_fn/nttp.cc
* testsuite/20_util/headers/functional/synopsis.cc
---
libstdc++-v3/include/bits/version.def | 12 ++
libstdc++-v3/include/bits/version.h | 21 +-
libstdc++-v3/include/std/functional | 124 +++++++++++-
.../20_util/function_objects/bind_back/1.cc | 22 +--
.../function_objects/bind_back/nttp.cc | 186 ++++++++++++++++++
.../20_util/function_objects/bind_front/1.cc | 16 +-
.../function_objects/bind_front/nttp.cc | 185 +++++++++++++++++
.../20_util/function_objects/not_fn/nttp.cc | 97 +++++++++
.../20_util/headers/functional/synopsis.cc | 22 +++
9 files changed, 662 insertions(+), 23 deletions(-)
create mode 100644
libstdc++-v3/testsuite/20_util/function_objects/bind_back/nttp.cc
create mode 100644
libstdc++-v3/testsuite/20_util/function_objects/bind_front/nttp.cc
create mode 100644
libstdc++-v3/testsuite/20_util/function_objects/not_fn/nttp.cc
diff --git a/libstdc++-v3/include/bits/version.def
b/libstdc++-v3/include/bits/version.def
index 5d5758bf203..8ab9a7207e7 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -463,6 +463,10 @@ ftms = {
ftms = {
name = not_fn;
+ values = {
+ v = 202306;
+ cxxmin = 26;
+ };
values = {
v = 201603;
cxxmin = 17;
@@ -776,6 +780,10 @@ ftms = {
ftms = {
name = bind_front;
+ values = {
+ v = 202306;
+ cxxmin = 26;
+ };
values = {
v = 201907;
cxxmin = 20;
@@ -784,6 +792,10 @@ ftms = {
ftms = {
name = bind_back;
+ values = {
+ v = 202306;
+ cxxmin = 26;
+ };
values = {
v = 202202;
cxxmin = 23;
diff --git a/libstdc++-v3/include/bits/version.h
b/libstdc++-v3/include/bits/version.h
index 2b00e8419b3..c204ae3c48c 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -511,7 +511,12 @@
#undef __glibcxx_want_make_from_tuple
#if !defined(__cpp_lib_not_fn)
-# if (__cplusplus >= 201703L)
+# if (__cplusplus > 202302L)
+# define __glibcxx_not_fn 202306L
+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_not_fn)
+# define __cpp_lib_not_fn 202306L
+# endif
+# elif (__cplusplus >= 201703L)
# define __glibcxx_not_fn 201603L
# if defined(__glibcxx_want_all) || defined(__glibcxx_want_not_fn)
# define __cpp_lib_not_fn 201603L
@@ -866,7 +871,12 @@
#undef __glibcxx_want_atomic_value_initialization
#if !defined(__cpp_lib_bind_front)
-# if (__cplusplus >= 202002L)
+# if (__cplusplus > 202302L)
+# define __glibcxx_bind_front 202306L
+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_bind_front)
+# define __cpp_lib_bind_front 202306L
+# endif
+# elif (__cplusplus >= 202002L)
# define __glibcxx_bind_front 201907L
# if defined(__glibcxx_want_all) || defined(__glibcxx_want_bind_front)
# define __cpp_lib_bind_front 201907L
@@ -876,7 +886,12 @@
#undef __glibcxx_want_bind_front
#if !defined(__cpp_lib_bind_back)
-# if (__cplusplus >= 202100L) && (__cpp_explicit_this_parameter)
+# if (__cplusplus > 202302L)
+# define __glibcxx_bind_back 202306L
+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_bind_back)
+# define __cpp_lib_bind_back 202306L
+# endif
+# elif (__cplusplus >= 202100L) && (__cpp_explicit_this_parameter)
# define __glibcxx_bind_back 202202L
# if defined(__glibcxx_want_all) || defined(__glibcxx_want_bind_back)
# define __cpp_lib_bind_back 202202L
diff --git a/libstdc++-v3/include/std/functional
b/libstdc++-v3/include/std/functional
index 307bcb95bcc..21f0b1cb2d5 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -940,7 +940,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_bound_args(std::forward<_Args>(__args)...)
{ static_assert(sizeof...(_Args) == sizeof...(_BoundArgs)); }
-#if __cpp_explicit_this_parameter
+#ifdef __cpp_explicit_this_parameter
template<typename _Self, typename... _CallArgs>
constexpr
invoke_result_t<__like_t<_Self, _Fd>, __like_t<_Self, _BoundArgs>...,
_CallArgs...>
@@ -1218,8 +1218,130 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
return _Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
}
+#if __cpp_lib_not_fn >= 202306
+ /** Wrap a function type to create a function object that negates its result.
+ *
+ * The function template `std::not_fn` creates a "forwarding call wrapper",
+ * which is a function object that when called forwards its arguments to
+ * its invocable template argument.
+ *
+ * The result of invoking the wrapper is the negation (using `!`) of
+ * the wrapped function object.
+ *
+ * @ingroup functors
+ * @since C++26
+ */
+ template<auto __fn>
+ constexpr auto
+ not_fn() noexcept
+ {
+ using _Fn = decltype(__fn);
+ if constexpr (is_pointer_v<_Fn> or is_member_pointer_v<_Fn>) {
+ static_assert(__fn != nullptr);
+ }
+ return []<typename... _Tp> (_Tp&&... __call_args)
+ noexcept(is_nothrow_invocable_v<_Fn, _Tp...>)
+ -> invoke_result_t<_Fn, _Tp...>
+ {
+ return !invoke(__fn, forward<_Tp>(__call_args)...);
+ };
+ }
+#endif // __cpp_lib_not_fn >= 202306
+#endif // __cpp_lib_not_fn
+
+#if __cpp_lib_bind_front >= 202306 || __cpp_lib_bind_back >= 202306
+
+ template<typename _Tp, typename _Up>
+ using __copy_const = conditional<is_const_v<_Tp>, const _Up, _Up>;
+
+ template<typename _Tp, typename _Up,
+ typename _Xp = __copy_const<remove_reference_t<_Tp>, _Up>::type>
+ using __copy_value_category =
+ conditional<is_lvalue_reference_v<_Tp&&>, _Xp&, _Xp&&>;
+
+ template<typename _Tp, typename _Up>
+ using __type_forward_like =
+ __copy_value_category<_Tp, remove_reference_t<_Up>>;
+
+ template<typename _Tp, typename _Up>
+ using __type_forward_like_t = __type_forward_like<_Tp, _Up>::type;
+
#endif
+#if __cpp_lib_bind_front >= 202306
+ /** Create call wrapper by partial application of arguments to function.
+ *
+ * The result of `std::bind_front<f>(args...)` is a function object that
+ * stores the bound arguments, `args...`. When that function object is
+ * invoked with `call_args...` it returns the result of calling
+ * `f(args..., call_args...)`.
+ *
+ * @since C++26
+ */
+
+ template<auto __fn, typename... _Args>
+ constexpr auto
+ bind_front(_Args&&... __args)
+ requires (
+ (is_constructible_v<decay_t<_Args>, _Args> and ...) and
+ (is_move_constructible_v<decay_t<_Args>> and ...))
+ {
+ using _Fn = decltype(__fn);
+ if constexpr (is_pointer_v<_Fn> or is_member_pointer_v<_Fn>) {
+ static_assert(__fn != nullptr);
+ }
+ return [... __bound_args(std::forward<_Args>(__args))]<
+ typename _Self, typename... _Tp>
+ (this _Self&&, _Tp&&... __call_args)
+ noexcept(is_nothrow_invocable_v<
+ _Fn, __type_forward_like_t<_Self, decay_t<_Args>>..., _Tp...>)
+ -> invoke_result_t<
+ _Fn, __type_forward_like_t<_Self, decay_t<_Args>>..., _Tp...>
+ {
+ return invoke(__fn,
+ forward_like<_Self>(__bound_args)...,
+ forward<_Tp>(__call_args)...);
+ };
+ }
+#endif // __cpp_lib_bind_front
+
+#if __cpp_lib_bind_back >= 202306
+ /** Create call wrapper by partial application of arguments to function.
+ *
+ * The result of `std::bind_back<f>(args...)` is a function object that
+ * stores the bound arguments, `args...`. When that function object is
+ * invoked with `call_args...` it returns the result of calling
+ * `f(call_args..., args...)`.
+ *
+ * @since C++26
+ */
+
+ template<auto __fn, typename... _Args>
+ constexpr auto
+ bind_back(_Args&&... __args)
+ requires (
+ (is_constructible_v<decay_t<_Args>, _Args> and ...) and
+ (is_move_constructible_v<decay_t<_Args>> and ...))
+ {
+ using _Fn = decltype(__fn);
+ if constexpr (is_pointer_v<_Fn> or is_member_pointer_v<_Fn>) {
+ static_assert(__fn != nullptr);
+ }
+ return [... __bound_args(std::forward<_Args>(__args))]<
+ typename _Self, typename... _Tp>
+ (this _Self&&, _Tp&&... __call_args)
+ noexcept(is_nothrow_invocable_v<
+ _Fn, _Tp..., __type_forward_like_t<_Self, decay_t<_Args>>...>)
+ -> invoke_result_t<
+ _Fn, _Tp..., __type_forward_like_t<_Self, decay_t<_Args>>...>
+ {
+ return invoke(__fn,
+ forward<_Tp>(__call_args)...,
+ forward_like<_Self>(__bound_args)...);
+ };
+ }
+#endif // __cpp_lib_bind_back
+
#if __cplusplus >= 201703L
// Searchers
diff --git a/libstdc++-v3/testsuite/20_util/function_objects/bind_back/1.cc
b/libstdc++-v3/testsuite/20_util/function_objects/bind_back/1.cc
index c31d3228815..feedead477b 100644
--- a/libstdc++-v3/testsuite/20_util/function_objects/bind_back/1.cc
+++ b/libstdc++-v3/testsuite/20_util/function_objects/bind_back/1.cc
@@ -149,23 +149,23 @@ test03()
static_assert(is_invocable_r_v<void*, const G4&&>);
}
-constexpr int f(int i, int j, int k) { return i + 2*(j + k); }
+constexpr int f(int i, int j, int k) { return i + 2*j + 3*k; }
-constexpr bool
+constexpr int
test04()
{
auto g = bind_back(f);
- VERIFY( g(1, 2, 3) == 1 + 2*(2 + 3) );
+ if (!( g(1, 2, 3) == 1 + 2*2 + 3*3 )) return 7;
auto g1 = bind_back(f, 1);
- VERIFY( g1(2, 3) == 2 + 2*(3 + 1) );
- VERIFY( bind_back(g, 1)(2, 3) == 2 + 2*(3 + 1) );
+ if (!( g1(2, 3) == 3*1 + 2 + 3*2)) return 6;
+ if (!( bind_back(g, 1)(2, 3) == 3*1 + 2 + 2*3 )) return 5;
auto g2 = bind_back(f, 1, 2);
- VERIFY( g2(3) == 3 + 2*(1 + 2) );
- VERIFY( bind_back(g1, 2)(3) == 3 + 2*(2 + 1) );
+ if (!( g2(3) == 3 + 2*1 + 3*2)) return 4;
+ if (!( bind_back(g1, 2)(3) == 3*1 + 2*2 + 3 )) return 3;
auto g3 = bind_back(f, 1, 2, 3);
- VERIFY( g3() == 1 + 2*(2 + 3) );
- VERIFY( bind_back(g2, 3)() == 3 + 2*(1 + 2) );
- return true;
+ if (!( g3() == 1 + 2*2 + 3*3 )) return 2;
+ if (!( bind_back(g2, 3)() == 3*1 + 1*2 + 2*3)) return 1;
+ return 0;
}
int
@@ -174,5 +174,5 @@ main()
test01();
test02();
test03();
- static_assert(test04());
+ static_assert(test04() == 0);
}
diff --git a/libstdc++-v3/testsuite/20_util/function_objects/bind_back/nttp.cc
b/libstdc++-v3/testsuite/20_util/function_objects/bind_back/nttp.cc
new file mode 100644
index 00000000000..d75f678fee3
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function_objects/bind_back/nttp.cc
@@ -0,0 +1,186 @@
+// { dg-do run { target c++26 } }
+// { dg-add-options no_pch }
+
+// Test NTTP bind_back<f>(Args...), P2714
+
+#include <functional>
+
+#ifndef __cpp_lib_bind_back
+# error "Feature test macro for bind_back is missing in <functional>"
+#elif __cpp_lib_bind_back < 202306L
+# error "Feature test macro for bind_back has wrong value in <functional>"
+#endif
+
+#include <testsuite_hooks.h>
+
+using std::bind_back;
+using std::is_same_v;
+using std::is_invocable_v;
+using std::is_invocable_r_v;
+
+void
+test01()
+{
+ struct F { void operator()() {} };
+ const F f{};
+
+ // [The following differ from the non-NTTP version of bind_back.]
+ // Arguments should be decayed:
+ // static_assert(std::is_same_v<
+ // decltype(bind_back<f>(std::declval<int>())),
+ // decltype(bind_back<f>(std::declval<int&>()))
+ // >);
+ // static_assert(std::is_same_v<
+ // decltype(bind_back<f>(std::declval<int>())),
+ // decltype(bind_back<f>(std::declval<const int&>()))
+ // >);
+
+ // Reference wrappers should be handled:
+ static_assert(!std::is_same_v<
+ decltype(bind_back<f>(std::declval<int&>())),
+ decltype(bind_back<f>(std::ref(std::declval<int&>())))
+ >);
+ static_assert(!std::is_same_v<
+ decltype(bind_back<f>(std::declval<const int&>())),
+ decltype(bind_back<f>(std::cref(std::declval<int&>())))
+ >);
+ static_assert(!std::is_same_v<
+ decltype(bind_back<f>(std::ref(std::declval<int&>()))),
+ decltype(bind_back<f>(std::cref(std::declval<int&>())))
+ >);
+}
+
+void
+test02()
+{
+ struct quals
+ {
+ bool as_const;
+ bool as_lvalue;
+ };
+
+ struct F
+ {
+ quals operator()() & { return { false, true }; }
+ quals operator()() const & { return { true, true }; }
+ quals operator()() && { return { false, false }; }
+ quals operator()() const && { return { true, false }; }
+ };
+
+ constexpr F f;
+ auto g = bind_back<f>();
+ const auto& cg = g;
+ quals q;
+
+ // Constness and value category forwarded to the target object?
+ // [This behavior differs from the non-NTTP bind_back:
+ // All uses call operator() const&.]
+ q = g();
+ // VERIFY( ! q.as_const && q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+ q = std::move(g)();
+ // VERIFY( ! q.as_const && ! q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+ q = cg();
+ VERIFY( q.as_const && q.as_lvalue );
+ q = std::move(cg)();
+ // VERIFY( q.as_const && ! q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+}
+
+void
+test03()
+{
+ struct F
+ {
+ int& operator()(void*, int& i) { return i; }
+ void* operator()(void* p, int) const { return p; }
+ };
+
+ int i = 5;
+ void* vp = &vp; // arbitrary void* value
+
+ F f;
+ auto g1 = bind_back<f>(i); // call wrapper has bound arg of type int
+ using G1 = decltype(g1);
+ // Invoking G1& will pass g1's bound arg as int&, so calls first overload:
+ static_assert(is_invocable_r_v<int&, G1&, void*>);
+ // Invoking const G1& or G&& calls second overload:
+ static_assert(is_invocable_r_v<void*, const G1&, void*>);
+ static_assert(is_invocable_r_v<void*, G1&&, void*>);
+ void* p1 = static_cast<G1&&>(g1)(vp);
+ VERIFY( p1 == vp );
+
+ // And can call first overload on const G6:
+ auto g2 = bind_back<f>(std::ref(i)); // bound arg of type int&
+ using G2 = decltype(g2);
+ // Bound arg always forwarded as int& even from G2&& or const G2&
+ static_assert(is_invocable_r_v<int&, G2&, void*>);
+ static_assert(is_invocable_r_v<int&, G2&&, void*>);
+
+ // [The following differ from the non-NTTP version of bind_back.]
+ // But cannot call first overload on const G2:
+ // static_assert(is_invocable_r_v<void*, const G2&, void*>);
+ // static_assert(is_invocable_r_v<void*, const G2&&, void*>);
+ // int& i2 = g2(vp);
+ // VERIFY( &i2 == &i );
+ // int& i2r = static_cast<G2&&>(g2)(vp);
+ // VERIFY( &i2r == &i );
+ // void* p2 = const_cast<const G2&>(g2)(vp);
+ // VERIFY( p2 == vp );
+
+ auto g3 = bind_back<f>(std::cref(i)); // bound arg of type const int&
+ using G3 = decltype(g3);
+ // Bound arg always forwarded as const int& so can only call second overload:
+ static_assert(is_invocable_r_v<void*, G3&, void*>);
+ static_assert(is_invocable_r_v<void*, G3&&, void*>);
+ static_assert(is_invocable_r_v<void*, const G3&, void*>);
+ static_assert(is_invocable_r_v<void*, const G3&&, void*>);
+
+ // [The following differ from the non-NTTP version of bind_back.]
+ // auto g4 = bind_back<g2>(nullptr);
+ // using G4 = decltype(g4);
+ // static_assert(is_invocable_r_v<int&, G4&>);
+ // static_assert(is_invocable_r_v<int&, G4&&>);
+ // static_assert(is_invocable_r_v<void*, const G4&>);
+ // static_assert(is_invocable_r_v<void*, const G4&&>);
+}
+
+constexpr int f(int i, int j, int k) { return i + 2*j + 3*k; }
+
+constexpr int
+test04()
+{
+ constexpr auto g = bind_back<f>();
+ if (!(g(1, 2, 3) == 1 + 2*2 + 3*3 )) return 7;
+ constexpr auto g1 = bind_back<f>(1);
+ if (!(g1(2, 3) == 3*1 + 1*2 + 2*3 )) return 6;
+ if (!(bind_back<g>(1)(2, 3) == 3*1 + 1*2 + 2*3 )) return 5;
+ constexpr auto g2 = bind_back<f>(1, 2);
+ if (!(g2(3) == 2*1 + 3*2 + 1*3 )) return 4;
+ if (!(bind_back<g1>(2)(3) == 3*1 + 2*2 + 1*3 )) return 3;
+ constexpr auto g3 = bind_back<f>(1, 2, 3);
+ if (!(g3() == 1 + 2*2 + 3*3)) return 2;
+ if (!(bind_back<g2>(3)() == 1*2 + 2*3 + 3*1 )) return 1;
+ return 0;
+}
+
+template <auto nnfp, auto nfp>
+void test05() {
+ VERIFY(bind_back<nnfp>(1)(2, 3) == 3*1 + 1*2 + 2*3);
+#if 0 // Fails to sandbox the static_assert(fp) in bind_back<fp>():
+ VERIFY(!requires { bind_back<nfp>(1); });
+#endif
+}
+
+int
+main()
+{
+ test01();
+ test02();
+ test03();
+ static_assert(test04() == 0);
+ constexpr int (*nnfp)(int, int, int) = f;
+ constexpr int (*nfp)(int, int, int) = nullptr;
+ test05<nnfp, nfp>();
+}
diff --git a/libstdc++-v3/testsuite/20_util/function_objects/bind_front/1.cc
b/libstdc++-v3/testsuite/20_util/function_objects/bind_front/1.cc
index 57482c52263..b038889fbb4 100644
--- a/libstdc++-v3/testsuite/20_util/function_objects/bind_front/1.cc
+++ b/libstdc++-v3/testsuite/20_util/function_objects/bind_front/1.cc
@@ -149,22 +149,22 @@ test03()
static_assert(is_invocable_r_v<void*, const G4&&>);
}
-int f(int i, int j, int k) { return i + j + k; }
+int f(int i, int j, int k) { return i + 2*j + 3*k; }
void
test04()
{
auto g = bind_front(f);
- VERIFY( g(1, 2, 3) == 6 );
+ VERIFY( g(1, 2, 3) == 14 );
auto g1 = bind_front(f, 1);
- VERIFY( g1(2, 3) == 6 );
- VERIFY( bind_front(g, 1)(2, 3) == 6 );
+ VERIFY( g1(2, 3) == 14 );
+ VERIFY( bind_front(g, 1)(2, 3) == 14 );
auto g2 = bind_front(f, 1, 2);
- VERIFY( g2(3) == 6 );
- VERIFY( bind_front(g1, 2)(3) == 6 );
+ VERIFY( g2(3) == 14 );
+ VERIFY( bind_front(g1, 2)(3) == 14 );
auto g3 = bind_front(f, 1, 2, 3);
- VERIFY( g3() == 6 );
- VERIFY( bind_front(g2, 3)() == 6 );
+ VERIFY( g3() == 14 );
+ VERIFY( bind_front(g2, 3)() == 14 );
}
int
diff --git a/libstdc++-v3/testsuite/20_util/function_objects/bind_front/nttp.cc
b/libstdc++-v3/testsuite/20_util/function_objects/bind_front/nttp.cc
new file mode 100644
index 00000000000..39465ef7cc1
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function_objects/bind_front/nttp.cc
@@ -0,0 +1,185 @@
+// { dg-do run { target c++26 } }
+// { dg-add-options no_pch }
+
+// Test NTTP bind_front<f>(Args...), P2714
+
+#include <functional>
+
+#ifndef __cpp_lib_bind_front
+# error "Feature test macro for bind_front is missing in <functional>"
+#elif __cpp_lib_bind_front < 201902L
+# error "Feature test macro for bind_front has wrong value in <functional>"
+#endif
+
+#include <testsuite_hooks.h>
+
+using std::bind_front;
+using std::is_same_v;
+using std::is_invocable_v;
+using std::is_invocable_r_v;
+
+void
+test01()
+{
+ struct F { void operator()() {} };
+ const F f{};
+
+ // [The following differ from the non-NTTP version of bind_front.]
+ // Arguments should be decayed:
+ // static_assert(std::is_same_v<
+ // decltype(bind_front<f>(std::declval<int>())),
+ // decltype(bind_front<f>(std::declval<int&>()))
+ // >);
+ // static_assert(std::is_same_v<
+ // decltype(bind_front<f>(std::declval<int>())),
+ // decltype(bind_front<f>(std::declval<const int&>()))
+ // >);
+
+ // Reference wrappers should be handled:
+ static_assert(!std::is_same_v<
+ decltype(bind_front<f>(std::declval<int&>())),
+ decltype(bind_front<f>(std::ref(std::declval<int&>())))
+ >);
+ static_assert(!std::is_same_v<
+ decltype(bind_front<f>(std::declval<const int&>())),
+ decltype(bind_front<f>(std::cref(std::declval<int&>())))
+ >);
+ static_assert(!std::is_same_v<
+ decltype(bind_front<f>(std::ref(std::declval<int&>()))),
+ decltype(bind_front<f>(std::cref(std::declval<int&>())))
+ >);
+}
+
+void
+test02()
+{
+ struct quals
+ {
+ bool as_const;
+ bool as_lvalue;
+ };
+
+ struct F
+ {
+ quals operator()() & { return { false, true }; }
+ quals operator()() const & { return { true, true }; }
+ quals operator()() && { return { false, false }; }
+ quals operator()() const && { return { true, false }; }
+ };
+
+ constexpr F f;
+ auto g = bind_front<f>();
+ const auto& cg = g;
+ quals q;
+
+ // Constness and value category forwarded to the target object?
+ // [This behavior differs from the non-NTTP bind_front:
+ // All uses call operator() const&.]
+ q = g();
+ // VERIFY( ! q.as_const && q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+ q = std::move(g)();
+ // VERIFY( ! q.as_const && ! q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+ q = cg();
+ VERIFY( q.as_const && q.as_lvalue );
+ q = std::move(cg)();
+ // VERIFY( q.as_const && ! q.as_lvalue );
+ VERIFY( q.as_const && q.as_lvalue );
+}
+
+void
+test03()
+{
+ struct F
+ {
+ int& operator()(int& i, void*) { return i; }
+ void* operator()(int, void* p) const { return p; }
+ };
+
+ int i = 5;
+ void* vp = &vp; // arbitrary void* value
+
+ F f;
+ auto g1 = bind_front<f>(i); // call wrapper has bound arg of type int
+ using G1 = decltype(g1);
+ // Invoking G1& will pass g1's bound arg as int&, so calls first overload:
+ static_assert(is_invocable_r_v<int&, G1&, void*>);
+ // Invoking const G1& or G&& calls second overload:
+ static_assert(is_invocable_r_v<void*, const G1&, void*>);
+ static_assert(is_invocable_r_v<void*, G1&&, void*>);
+ void* p1 = static_cast<G1&&>(g1)(vp);
+ VERIFY( p1 == vp );
+
+ // And can call first overload on const G6:
+ auto g2 = bind_front<f>(std::ref(i)); // bound arg of type int&
+ using G2 = decltype(g2);
+ // Bound arg always forwarded as int& even from G2&& or const G2&
+ static_assert(is_invocable_r_v<int&, G2&, void*>);
+ static_assert(is_invocable_r_v<int&, G2&&, void*>);
+
+ // [The following differ from the non-NTTP version of bind_front.]
+ // But cannot call first overload on const G2:
+ // static_assert(is_invocable_r_v<void*, const G2&, void*>);
+ // static_assert(is_invocable_r_v<void*, const G2&&, void*>);
+ // int& i2 = g2(vp);
+ // VERIFY( &i2 == &i );
+ // int& i2r = static_cast<G2&&>(g2)(vp);
+ // VERIFY( &i2r == &i );
+ // void* p2 = const_cast<const G2&>(g2)(vp);
+ // VERIFY( p2 == vp );
+
+ auto g3 = bind_front<f>(std::cref(i)); // bound arg of type const int&
+ using G3 = decltype(g3);
+ // Bound arg always forwarded as const int& so can only call second overload:
+ static_assert(is_invocable_r_v<void*, G3&, void*>);
+ static_assert(is_invocable_r_v<void*, G3&&, void*>);
+ static_assert(is_invocable_r_v<void*, const G3&, void*>);
+ static_assert(is_invocable_r_v<void*, const G3&&, void*>);
+
+ // [The following differ from the non-NTTP version of bind_front.]
+ // auto g4 = bind_front<g2>(nullptr);
+ // using G4 = decltype(g4);
+ // static_assert(is_invocable_r_v<int&, G4&>);
+ // static_assert(is_invocable_r_v<int&, G4&&>);
+ // static_assert(is_invocable_r_v<void*, const G4&>);
+ // static_assert(is_invocable_r_v<void*, const G4&&>);
+}
+
+constexpr int f(int i, int j, int k) { return i + 2*j + 3*k; }
+
+void
+test04()
+{
+ constexpr auto g = bind_front<f>();
+ VERIFY( g(1, 2, 3) == 14 );
+ constexpr auto g1 = bind_front<f>(1);
+ VERIFY( g1(2, 3) == 14 );
+ VERIFY( bind_front<g>(1)(2, 3) == 14 );
+ constexpr auto g2 = bind_front<f>(1, 2);
+ VERIFY( g2(3) == 14 );
+ VERIFY( bind_front<g1>(2)(3) == 14 );
+ constexpr auto g3 = bind_front<f>(1, 2, 3);
+ VERIFY( g3() == 14 );
+ VERIFY( bind_front<g2>(3)() == 14 );
+}
+
+template <auto nnfp, auto nfp>
+constexpr void test05() {
+ VERIFY(bind_front<nnfp>(1)(2, 3) == 14);
+#if 0 // Fails to sandbox the static_assert(fp) in bind_front<fp>():
+ VERIFY(!requires { bind_front<nfp>(1); });
+#endif
+}
+
+int
+main()
+{
+ test01();
+ test02();
+ test03();
+ test04();
+ constexpr int (*nnfp)(int, int, int) = f;
+ constexpr int (*nfp)(int, int, int) = nullptr;
+ test05<nnfp, nfp>();
+}
diff --git a/libstdc++-v3/testsuite/20_util/function_objects/not_fn/nttp.cc
b/libstdc++-v3/testsuite/20_util/function_objects/not_fn/nttp.cc
new file mode 100644
index 00000000000..f08e48f4157
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function_objects/not_fn/nttp.cc
@@ -0,0 +1,97 @@
+// Test NTTP version of not_fn, from P2714
+
+// { dg-do run { target c++26 } }
+
+#ifndef __cpp_lib_bind_back
+# error "Feature test macro for bind_back is missing in <functional>"
+#elif __cpp_lib_bind_back < 202306L
+# error "Feature test macro for bind_back has wrong value in <functional>"
+#endif
+
+#include <functional>
+#include <testsuite_hooks.h>
+
+using std::not_fn;
+
+int func(int, char) { return 0; }
+
+struct F
+{
+ bool operator()() { return false; }
+ bool operator()() const { return true; }
+ bool operator()(int) const { return false; }
+};
+
+void
+test01()
+{
+ auto f1 = not_fn<func>();
+ VERIFY( f1(1, '2') == true );
+
+ auto f2 = not_fn<[] { return true; }>();
+ VERIFY( f2() == false );
+
+ auto f3 = not_fn<F{}>();
+ VERIFY( f3() == false ); // Prefer the const member.
+ VERIFY( f3(1) == true );
+ const auto f4 = f3;
+ VERIFY( f4() == false );
+}
+
+void
+test04()
+{
+ struct abstract { virtual void f() = 0; };
+ struct derived : abstract { void f() { } };
+ struct F { bool operator()(abstract&) const { return false; } };
+ constexpr F f;
+ derived d;
+ VERIFY( not_fn<f>()(d) );
+}
+
+void
+test05()
+{
+ auto nf = std::not_fn<[] { return false; }>();
+ auto copy(nf); // PR libstdc++/70564
+}
+
+void
+test06()
+{
+ struct Boolean {
+ Boolean operator!() noexcept(false) { return *this; }
+ };
+ struct F {
+ Boolean operator()() { return {}; }
+ };
+ F f;
+ auto notf = std::not_fn<f>();
+ using NotF = decltype(notf);
+ static_assert( std::is_invocable<NotF>::value, "cannot negate" );
+ static_assert( !noexcept(notf()), "conversion to bool affects noexcept" );
+}
+
+void
+test07()
+{
+ struct NonNegatable { }; // there is no operator!(NonNegatable)
+ struct F {
+ NonNegatable operator()() const { return {}; }
+ };
+ F f;
+ constexpr auto notf = std::not_fn<f>();
+ using NotF = decltype(notf);
+ // [This check fails for NTTP not_fn, even though invoking it fails. ]
+ // static_assert( !std::is_invocable<NotF>::value, "cannot negate" );
+}
+
+int
+main()
+{
+ test01();
+ test04();
+ test05();
+ test06();
+ test07();
+}
diff --git a/libstdc++-v3/testsuite/20_util/headers/functional/synopsis.cc
b/libstdc++-v3/testsuite/20_util/headers/functional/synopsis.cc
index e3e92076f5c..0af3504dc3a 100644
--- a/libstdc++-v3/testsuite/20_util/headers/functional/synopsis.cc
+++ b/libstdc++-v3/testsuite/20_util/headers/functional/synopsis.cc
@@ -57,6 +57,13 @@ namespace std {
template <class Predicate>
_GLIBCXX14_CONSTEXPR
binary_negate<Predicate> not2(const Predicate&);
+#ifdef __cpp_lib_not_fn
+ template <typename F> _GLIBCXX20_CONSTEXPR auto not_fn(F&&)
+ noexcept(std::is_nothrow_constructible<std::decay_t<F>, F&&>::value);
+#if __cpp_lib_not_fn >= 2020306
+ template <auto f> constexpr auto not_fn() noexcept;
+#endif
+#endif
// lib.binders, binders:
template <class Operation> class binder1st;
@@ -65,6 +72,20 @@ namespace std {
template <class Operation> class binder2nd;
template <class Operation, class T>
binder2nd<Operation> bind2nd(const Operation&, const T&);
+#ifdef __cpp_lib_bind_front
+ template <typename F, typename... Args>
+ _GLIBCXX20_CONSTEXPR auto bind_front(F&&, Args&&...);
+#if __cpp_lib_bind_front >= 202306
+ template <auto f, typename... Args> constexpr auto bind_front(Args&&...);
+#endif
+#endif
+#ifdef __cpp_lib_bind_back
+ template <typename F, typename... Args>
+ _GLIBCXX20_CONSTEXPR auto bind_back(F&&, Args&&...);
+#if __cpp_lib_bind_back >= 202306
+ template <auto f, typename... Args> constexpr auto bind_back(Args&&...);
+#endif
+#endif
// lib.function.pointer.adaptors, adaptors:
template <class Arg, class Result> class pointer_to_unary_function;
@@ -102,4 +123,5 @@ namespace std {
const_mem_fun_ref_t<S,T> mem_fun_ref(S (T::*f)() const);
template <class S, class T, class A>
const_mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A) const);
+
}
--
2.50.0
