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_bind_expression; 14 // A program may specialize this template for a program-defined type T 15 // to have a base characteristic of true_type to indicate that T should 16 // be treated as a subexpression in a bind call. 17 // https://llvm.org/PR51753 18 19 #include <functional> 20 #include <cassert> 21 #include <type_traits> 22 23 struct MyBind { 24 int operator()(int x, int y) const { return 10*x + y; } 25 }; 26 template<> struct std::is_bind_expression<MyBind> : std::true_type {}; 27 28 int main(int, char**) 29 { 30 { 31 auto f = [](auto x) { return 10*x + 9; }; 32 MyBind bindexpr; 33 auto bound = std::bind(f, bindexpr); 34 assert(bound(7, 8) == 789); 35 } 36 { 37 auto f = [](auto x) { return 10*x + 9; }; 38 const MyBind bindexpr; 39 auto bound = std::bind(f, bindexpr); 40 assert(bound(7, 8) == 789); 41 } 42 { 43 auto f = [](auto x) { return 10*x + 9; }; 44 MyBind bindexpr; 45 auto bound = std::bind(f, std::move(bindexpr)); 46 assert(bound(7, 8) == 789); 47 } 48 { 49 auto f = [](auto x) { return 10*x + 9; }; 50 const MyBind bindexpr; 51 auto bound = std::bind(f, std::move(bindexpr)); 52 assert(bound(7, 8) == 789); 53 } 54 55 return 0; 56 } 57