libstdc++-v3/testsuite/30_threads/call_once/60497.cc

   1 // { dg-do compile { target c++11 } }
   2 // { dg-additional-options "-pthread" { target pthread } }
   3
   4 // Copyright (C) 2014-2022 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 // libstdc++/60497
  22
  23 #include <mutex>
  24 #include <memory>
  25 #include <functional>
  26
  27 struct A;
  28 template<typename T> struct B { T t; };
  29
  30 using UP = std::unique_ptr<B<A>>;
  31
  32 void f(UP&) { }
  33
  34 void g(UP& p)
  35 {
  36   std::once_flag o;
  37   std::call_once(o, f, std::ref(p));
  38 }