ACE/ace/Test_and_Set.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file   Test_and_Set.h
   6  */
   7 //=============================================================================
   8
   9
  10 #ifndef ACE_TEST_AND_SET_H
  11 #define ACE_TEST_AND_SET_H
  12
  13 #include /**/ "ace/pre.h"
  14 #include "ace/Event_Handler.h"
  15
  16 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  17 # pragma once
  18 #endif /* ACE_LACKS_PRAGMA_ONCE */
  19
  20 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  21
  22 /**
  23  * @class ACE_Test_and_Set
  24  *
  25  * @brief Implements the classic ``test and set'' operation.
  26  *
  27  *     This class keeps track of the status of <is_set_>, which can be
  28  *     set based on various events (such as receipt of a signal).
  29  *     This class is derived from ACE_Event_Handler so that it can be
  30  *     "signaled" by a Reactor when a signal occurs.  We assume that
  31  *     <TYPE> is a data type that can be assigned the value 0 or 1.
  32  */
  33 template <class ACE_LOCK, class TYPE>
  34 class ACE_Test_and_Set : public ACE_Event_Handler
  35 {
  36 public:
  37   ACE_Test_and_Set (TYPE initial_value = 0);
  38
  39   /// Returns true if we are set, else false.
  40   TYPE is_set (void) const;
  41
  42   /// Sets the <is_set_> status, returning the original value of
  43   /// <is_set_>.
  44   TYPE set (TYPE);
  45
  46   /// Called when object is signaled by OS (either via UNIX signals or
  47   /// when a Win32 object becomes signaled).
  48   virtual int handle_signal (int signum,
  49                              siginfo_t * = 0,
  50                              ucontext_t * = 0);
  51
  52 private:
  53   /// Keeps track of our state.
  54   TYPE is_set_;
  55
  56   /// Protect the state from race conditions.
  57   ACE_LOCK lock_;
  58 };
  59
  60 ACE_END_VERSIONED_NAMESPACE_DECL
  61
  62 #if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
  63 #include "ace/Test_and_Set.cpp"
  64 #endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
  65
  66 #if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
  67 #pragma implementation ("Test_and_Set.cpp")
  68 #endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
  69
  70 #include /**/ "ace/post.h"
  71 #endif /* ACE_TEST_AND_SET_H */