1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // UNSUPPORTED: c++03, c++11
10
11 // <functional>
12
13 // template<class T> struct is_placeholder;
14 // A program may specialize this template for a program-defined type T
15 // to have a base characteristic of integral_constant<int, N> with N > 0
16 // to indicate that T should be treated as a placeholder type.
17 // https://llvm.org/PR51753
18
19 #include <functional>
20 #include <cassert>
21 #include <type_traits>
22
23 struct My2 {};
24 template<> struct std::is_placeholder<My2> : std::integral_constant<int, 2> {};
25
main(int,char **)26 int main(int, char**)
27 {
28 {
29 auto f = [](auto x) { return 10*x + 9; };
30 My2 place;
31 auto bound = std::bind(f, place);
32 assert(bound(7, 8) == 89);
33 }
34 {
35 auto f = [](auto x) { return 10*x + 9; };
36 const My2 place;
37 auto bound = std::bind(f, place);
38 assert(bound(7, 8) == 89);
39 }
40 {
41 auto f = [](auto x) { return 10*x + 9; };
42 My2 place;
43 auto bound = std::bind(f, std::move(place));
44 assert(bound(7, 8) == 89);
45 }
46 {
47 auto f = [](auto x) { return 10*x + 9; };
48 const My2 place;
49 auto bound = std::bind(f, std::move(place));
50 assert(bound(7, 8) == 89);
51 }
52
53 return 0;
54 }
55