libstdc++-v3/testsuite/20_util/function/invoke/forwarding.cc

   1 // Copyright (C) 2014-2022 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-do run { target c++11 } }
  19 // { dg-require-effective-target hosted }
  20
  21 #include <functional>
  22 #include <testsuite_hooks.h>
  23
  24 struct Counted
  25 {
  26   Counted() : count(0) { }
  27   Counted(const Counted& c) : count(c.count + 1) { }
  28   int count;
  29 };
  30
  31 int func(Counted c) { return c.count; }
  32
  33 std::function<int(Counted)> f = func;
  34
  35 void
  36 test01()
  37 {
  38   Counted c;
  39   int n = f(c);
  40   // 1 copy invoking function::operator() and 1 copy invoking func
  41   VERIFY( n == 2 );
  42 }
  43
  44 void
  45 test02()
  46 {
  47   int n = f(Counted{});
  48   // copy elided when invoking function::operator(), 1 copy invoking func
  49   VERIFY( n == 1 );
  50 }
  51
  52 int
  53 main()
  54 {
  55   test01();
  56   test02();
  57 }