ceph/src/boost/libs/thread/include/boost/thread/detail/singleton.hpp

   1 // Copyright (C) 2001-2003
   2 // Mac Murrett
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See
   5 // accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // See http://www.boost.org for most recent version including documentation.
   9
  10 #ifndef BOOST_SINGLETON_MJM012402_HPP
  11 #define BOOST_SINGLETON_MJM012402_HPP
  12
  13 #include <boost/thread/detail/config.hpp>
  14
  15 namespace boost {
  16 namespace detail {
  17 namespace thread {
  18
  19 // class singleton has the same goal as all singletons: create one instance of
  20 // a class on demand, then dish it out as requested.
  21
  22 template <class T>
  23 class singleton : private T
  24 {
  25 private:
  26     singleton();
  27     ~singleton();
  28
  29 public:
  30     static T &instance();
  31 };
  32
  33
  34 template <class T>
  35 inline singleton<T>::singleton()
  36 {
  37     /* no-op */
  38 }
  39
  40 template <class T>
  41 inline singleton<T>::~singleton()
  42 {
  43     /* no-op */
  44 }
  45
  46 template <class T>
  47 /*static*/ T &singleton<T>::instance()
  48 {
  49     // function-local static to force this to work correctly at static
  50     // initialization time.
  51     static singleton<T> s_oT;
  52     return(s_oT);
  53 }
  54
  55 } // namespace thread
  56 } // namespace detail
  57 } // namespace boost
  58
  59 #endif // BOOST_SINGLETON_MJM012402_HPP