| // Copyright (C) 2016-2023 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING3. If not see |
| // <http://www.gnu.org/licenses/>. |
| |
| // { dg-do compile { target c++11 } } |
| // { dg-require-effective-target hosted } |
| |
| #include <memory> |
| |
| template<typename T, typename Args, typename = void> |
| struct resettable |
| : std::false_type |
| { }; |
| |
| template<typename... T> struct type_list { }; |
| |
| template<typename T, typename... Args> |
| using reset_result |
| = decltype(std::shared_ptr<T>{}.reset(std::declval<Args>()...)); |
| |
| template<typename T, typename... Args> |
| struct resettable<T, type_list<Args...>, reset_result<T, Args...>> |
| : std::true_type |
| { }; |
| |
| template<typename T, typename... Args> |
| constexpr bool can_reset() |
| { return resettable<T, type_list<Args...>>::value; } |
| |
| template<typename T> |
| struct Deleter { |
| void operator()(T*) const; |
| }; |
| |
| template<typename T> |
| using Alloc = std::allocator<T>; |
| |
| struct Base { }; |
| struct Derived : Base { }; |
| |
| // Positive cases: |
| |
| static_assert( can_reset<const void, void*>(), |
| "void* convertible to const void*"); |
| static_assert( can_reset<const int, int*>(), |
| "int* convertible to const int*"); |
| static_assert( can_reset<Base, Derived*>(), |
| "Derived* convertible to Base*"); |
| static_assert( can_reset<const Base, Derived*>(), |
| "Derived* convertible to const Base*"); |
| |
| // Negative cases: |
| |
| static_assert( !can_reset<int, void*>(), |
| "void* not convertible to int*"); |
| static_assert( !can_reset<int, void*, Deleter<int>>(), |
| "void* not convertible to int*"); |
| static_assert( !can_reset<int, void*, Deleter<int>, Alloc<int>>(), |
| "void* not convertible to int*"); |
| |
| static_assert( !can_reset<int, const int*>(), |
| "const int* not convertible to int*"); |
| static_assert( !can_reset<int, const int*, Deleter<int>>(), |
| "const int* not convertible to int*"); |
| static_assert( !can_reset<int, const int*, Deleter<int>, Alloc<int>>(), |
| "const int* not convertible to int*"); |
| |
| static_assert( !can_reset<int, long*>(), |
| "long* not convertible to int*"); |
| static_assert( !can_reset<int, long*, Deleter<int>>(), |
| "long* not convertible to int*"); |
| static_assert( !can_reset<int, long*, Deleter<int>, Alloc<int>>(), |
| "long* not convertible to int*"); |
| |
| static_assert( !can_reset<Derived, Base*>(), |
| "Base* not convertible to Derived*"); |
| static_assert( !can_reset<Derived, Base*, Deleter<int>>(), |
| "Base* not convertible to Derived*"); |
| static_assert( !can_reset<Derived, Base*, Deleter<int>, Alloc<int>>(), |
| "Base* not convertible to Derived*"); |