libstdc++-v3/testsuite/20_util/bind/constexpr.cc

   1 // Copyright (C) 2019-2021 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++2a" }
  19 // { dg-do compile { target c++2a } }
  20
  21 #include <functional>
  22
  23 struct add
  24 {
  25   constexpr int operator()(int i, int j) const { return i + j; }
  26 };
  27
  28 constexpr int
  29 test01(int i, int j)
  30 {
  31   add a;
  32   return std::bind(a, i, std::placeholders::_1)(j);
  33 }
  34
  35 static_assert( test01(1, 2) == 3 );
  36
  37 constexpr int
  38 test02(int i, int j)
  39 {
  40   return std::bind<int>(add{}, i, std::placeholders::_1)(j);
  41 }
  42
  43 static_assert( test02(4, 5) == 9 );