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7c3769df62
to reflect the new license. These used slightly different spellings that defeated my regular expressions. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@351648 91177308-0d34-0410-b5e6-96231b3b80d8
97 lines
3.1 KiB
C++
97 lines
3.1 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <functional>
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// reference_wrapper
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// has weak result type
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#include <functional>
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#include <type_traits>
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template <class Arg, class Result>
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struct my_unary_function
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{ // std::unary_function was removed in C++17
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typedef Arg argument_type;
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typedef Result result_type;
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};
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template <class Arg1, class Arg2, class Result>
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struct my_binary_function
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{ // std::binary_function was removed in C++17
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typedef Arg1 first_argument_type;
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typedef Arg2 second_argument_type;
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typedef Result result_type;
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};
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class functor1
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: public my_unary_function<int, char>
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{
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};
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class functor2
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: public my_binary_function<char, int, double>
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{
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};
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class functor3
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: public my_unary_function<char, int>,
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public my_binary_function<char, int, double>
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{
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public:
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typedef float result_type;
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};
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class functor4
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: public my_unary_function<char, int>,
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public my_binary_function<char, int, double>
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{
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public:
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};
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class C {};
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template <class T>
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struct has_result_type
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{
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private:
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struct two {char _; char __;};
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template <class U> static two test(...);
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template <class U> static char test(typename U::result_type* = 0);
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public:
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static const bool value = sizeof(test<T>(0)) == 1;
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};
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int main()
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{
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static_assert((std::is_same<std::reference_wrapper<functor1>::result_type,
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char>::value), "");
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static_assert((std::is_same<std::reference_wrapper<functor2>::result_type,
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double>::value), "");
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static_assert((std::is_same<std::reference_wrapper<functor3>::result_type,
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float>::value), "");
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static_assert((std::is_same<std::reference_wrapper<void()>::result_type,
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void>::value), "");
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static_assert((std::is_same<std::reference_wrapper<int*(double*)>::result_type,
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int*>::value), "");
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static_assert((std::is_same<std::reference_wrapper<void(*)()>::result_type,
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void>::value), "");
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static_assert((std::is_same<std::reference_wrapper<int*(*)(double*)>::result_type,
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int*>::value), "");
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static_assert((std::is_same<std::reference_wrapper<int*(C::*)(double*)>::result_type,
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int*>::value), "");
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static_assert((std::is_same<std::reference_wrapper<int (C::*)(double*) const volatile>::result_type,
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int>::value), "");
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static_assert((std::is_same<std::reference_wrapper<C()>::result_type,
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C>::value), "");
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static_assert(has_result_type<std::reference_wrapper<functor3> >::value, "");
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static_assert(!has_result_type<std::reference_wrapper<functor4> >::value, "");
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static_assert(!has_result_type<std::reference_wrapper<C> >::value, "");
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}
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