libstdc++-v3/testsuite/30_threads/stop_token/stop_callback/deadlock.cc

   1 // Copyright (C) 2020-2021 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-add-options libatomic }
  20 // { dg-do run { target c++2a } }
  21
  22 #include <stop_token>
  23 #include <memory>
  24 #include <testsuite_hooks.h>
  25
  26 void
  27 test01()
  28 {
  29   std::stop_source ssrc;
  30   std::stop_token stok = ssrc.get_token();
  31   using F = void(*)();
  32   std::unique_ptr<std::stop_callback<F>> pcb;
  33   auto dereg = [&pcb] { pcb.reset(); };
  34   std::stop_callback cb1(stok, dereg);
  35   pcb = std::make_unique<std::stop_callback<F>>(stok, []{});
  36   std::stop_callback cb2(stok, dereg);
  37
  38   // PR libstdc++/92895
  39   // Making a stop request runs the callbacks. Whichever of cb1 and cb2
  40   // runs first will destroy *pcb, which will try to unregister it.
  41   // This recursive access to the shared stop state within a callback must
  42   // work without deadlock.
  43   ssrc.request_stop();
  44 }
  45
  46 int main()
  47 {
  48   test01();
  49 }