1 // Mutex pool used to limit contention -*- C++ -*-
2
3 // Copyright (C) 2016-2017 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
_GLIBCXX_VISIBILITY(hidden)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 }
35