libstdc++-v3/testsuite/30_threads/lock_guard/cons/deduction.cc

   1 // Copyright (C) 2017-2019 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++17" }
  19 // { dg-do compile { target c++17 } }
  20
  21 #include <mutex>
  22
  23 template<typename T, typename U> struct require_same;
  24 template<typename T> struct require_same<T, T> { using type = void; };
  25
  26 template<typename T, typename U>
  27   typename require_same<T, U>::type
  28   check_type(U&) { }
  29
  30 void
  31 test01()
  32 {
  33   std::mutex m;
  34   std::lock_guard l(m);
  35   check_type<std::lock_guard<std::mutex>>(l);
  36
  37   struct Mutex {
  38     void lock() { }
  39     void unlock() { }
  40   } m2;
  41
  42   std::lock_guard l2(m2);
  43   check_type<std::lock_guard<Mutex>>(l2);
  44 }