namespace boost {
  class barrier;
}

namespace boost {
  class condition;
}

namespace boost {
  class lock_error;
  class thread_resource_error;
}

namespace boost {
  class mutex;
  class try_mutex;
  class timed_mutex;
}

BOOST_ONCE_INIT

namespace boost {
  typedef implementation-defined once_flag;  // The call_once function and
			once_flag type (statically initialized to 
			BOOST_ONCE_INIT) can be used to run a
			routine exactly once. This can be used to initialize data in a
			thread-safe
			manner.
   call_once(void (*func)(), once_flag&);
}

namespace boost {
  class recursive_mutex;
  class recursive_try_mutex;
  class recursive_timed_mutex;
}

namespace boost {
  class thread;
  class thread_group;
}

namespace boost {
  class thread_specific_ptr;
}

namespace boost {
  enum xtime_clock_types;

  struct xtime;
  int xtime_get(xtime*, int);
}