// $Id$

#ifndef ACE_TEST_AND_SET_H
#define ACE_TEST_AND_SET_H

#include "ace/pre.h"
#include "ace/Event_Handler.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

template <class ACE_LOCK, class TYPE>
class ACE_Export ACE_Test_and_Set : public ACE_Event_Handler
{
public:
  // = TITLE
  //     Implements the classic ``test and set'' operation.
  //
  // = DESCRIPTION
  //     This class keeps track of the status of <is_set_>, which can
  //     be set based on various events (such as receipt of a
  //     signal).  This class is derived from <ACE_Event_Handler> so
  //     that it can be "signaled" by a Reactor when a signal occurs.
  //     We assume that <TYPE> is a data type that can be assigned the
  //     value 0 or 1.
  ACE_Test_and_Set (TYPE initial_value = 0);

  TYPE is_set (void) const;
  // Returns true if we are set, else false.

  TYPE set (TYPE);
  // Sets the <is_set_> status, returning the original value of
  // <is_set_>.

  virtual int handle_signal (int signum,
                             siginfo_t * = 0,
                             ucontext_t * = 0);
  // Called when object is signaled by OS (either via UNIX signals or
  // when a Win32 object becomes signaled).

private:
  TYPE is_set_;
  // Keeps track of our state.

  ACE_LOCK lock_;
  // Protect the state from race conditions.
};

#if defined (__ACE_INLINE__)
#include "ace/Test_and_Set.i"
#endif /* __ACE_INLINE__ */

#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Test_and_Set.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */

#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Test_and_Set.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */

#include "ace/post.h"
#endif /* ACE_TEST_AND_SET_H */