libstdc++-v3/src/c++11/mutex_pool.h

   1 // Mutex pool used to limit contention -*- C++ -*-
   2
   3 // Copyright (C) 2016 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 namespace __gnu_internal _GLIBCXX_VISIBILITY(hidden)
  26 {
  27   const unsigned char mask = 0xf;
  28   const unsigned char invalid = mask + 1;
  29
  30   /* Returns different instances of __mutex depending on the passed index
  31    * in order to limit contention.
  32    */
  33   __gnu_cxx::__mutex& get_mutex(unsigned char i);
  34 }