ceph/src/boost/libs/smart_ptr/include/boost/smart_ptr/detail/atomic_count_gcc.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_HPP_INCLUDED
   3
   4 //
   5 //  boost/detail/atomic_count_gcc.hpp
   6 //
   7 //  atomic_count for GNU libstdc++ v3
   8 //
   9 //  http://gcc.gnu.org/onlinedocs/porting/Thread-safety.html
  10 //
  11 //  Copyright (c) 2001, 2002 Peter Dimov and Multi Media Ltd.
  12 //  Copyright (c) 2002 Lars Gullik Bjønnes <larsbj@lyx.org>
  13 //  Copyright 2003-2005 Peter Dimov
  14 //
  15 //  Distributed under the Boost Software License, Version 1.0. (See
  16 //  accompanying file LICENSE_1_0.txt or copy at
  17 //  http://www.boost.org/LICENSE_1_0.txt)
  18 //
  19
  20 #if __GNUC__ * 100 + __GNUC_MINOR__ >= 402
  21 # include <ext/atomicity.h>
  22 #else
  23 # include <bits/atomicity.h>
  24 #endif
  25
  26 namespace boost
  27 {
  28
  29 namespace detail
  30 {
  31
  32 #if defined(__GLIBCXX__) // g++ 3.4+
  33
  34 using __gnu_cxx::__atomic_add;
  35 using __gnu_cxx::__exchange_and_add;
  36
  37 #endif
  38
  39 class atomic_count
  40 {
  41 public:
  42
  43     explicit atomic_count( long v ) : value_( v ) {}
  44
  45     long operator++()
  46     {
  47         return __exchange_and_add( &value_, +1 ) + 1;
  48     }
  49
  50     long operator--()
  51     {
  52         return __exchange_and_add( &value_, -1 ) - 1;
  53     }
  54
  55     operator long() const
  56     {
  57         return __exchange_and_add( &value_, 0 );
  58     }
  59
  60 private:
  61
  62     atomic_count(atomic_count const &);
  63     atomic_count & operator=(atomic_count const &);
  64
  65     mutable _Atomic_word value_;
  66 };
  67
  68 } // namespace detail
  69
  70 } // namespace boost
  71
  72 #endif // #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_HPP_INCLUDED