// { dg-do run { target c++11 } } // 2005-01-15 Douglas Gregor // // Copyright (C) 2005-2017 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 // . // 20.7.15 polymorphic function object wrapper #include #include template const T& as_const(T& t) { return t; } // Check that f's target is a reference_wrapper bound to obj. template bool wraps(Function& f, T& obj) { using ref_wrapper_type = std::reference_wrapper; auto* p = f.template target(); return std::addressof(p->get()) == std::addressof(obj); } struct secret {}; struct noncopyable_function_object_type { noncopyable_function_object_type(secret) {} int operator()() const { return 42; } int operator()() { return 17; } private: noncopyable_function_object_type(); noncopyable_function_object_type(const noncopyable_function_object_type&); void operator=(const noncopyable_function_object_type&); }; // Put reference_wrappers into function<> wrappers void test06() { using std::function; using std::ref; using std::cref; secret password; noncopyable_function_object_type x(password); function f(ref(x)); VERIFY( f ); VERIFY( f() == 17 ); VERIFY( f.target_type() == typeid(std::ref(x)) ); // LWG 2781 VERIFY( wraps(f, x) ); function g = f; VERIFY( g ); VERIFY( g() == 17 ); VERIFY( g.target_type() == f.target_type() ); VERIFY( wraps(g, x) ); function h = cref(x); VERIFY( h ); VERIFY( h() == 42 ); VERIFY( h.target_type() == typeid(std::cref(x)) ); VERIFY( wraps(h, as_const(x)) ); const function& hc = h; VERIFY( hc.target_type() == h.target_type() ); VERIFY( wraps(hc, as_const(x)) ); } int main() { test06(); return 0; }