7afa1598a3
compressed_pair is widely used in the library, but most of the uses don't use the tuple parts. To avoid including <tuple> everywhere, use the forward declaration instead in compressed_pair.h Reviewed By: ldionne, #libc Spies: libcxx-commits Differential Revision: https://reviews.llvm.org/D133331
56 lines
1.5 KiB
C++
56 lines
1.5 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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// UNSUPPORTED: c++03, c++11
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// <functional>
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// template<class T> struct is_placeholder;
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// A program may specialize this template for a program-defined type T
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// to have a base characteristic of integral_constant<int, N> with N > 0
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// to indicate that T should be treated as a placeholder type.
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// https://llvm.org/PR51753
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#include <cassert>
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#include <functional>
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#include <type_traits>
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#include <utility>
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struct My2 {};
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template<> struct std::is_placeholder<My2> : std::integral_constant<int, 2> {};
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int main(int, char**)
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{
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{
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auto f = [](auto x) { return 10*x + 9; };
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My2 place;
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auto bound = std::bind(f, place);
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assert(bound(7, 8) == 89);
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}
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{
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auto f = [](auto x) { return 10*x + 9; };
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const My2 place;
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auto bound = std::bind(f, place);
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assert(bound(7, 8) == 89);
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}
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{
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auto f = [](auto x) { return 10*x + 9; };
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My2 place;
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auto bound = std::bind(f, std::move(place));
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assert(bound(7, 8) == 89);
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}
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{
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auto f = [](auto x) { return 10*x + 9; };
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const My2 place;
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auto bound = std::bind(f, std::move(place));
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assert(bound(7, 8) == 89);
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}
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return 0;
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}
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