ACE/ace/Log_Msg_Callback.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Log_Msg_Callback.h
   6  *
   7  *  @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef ACE_LOG_MSG_CALLBACK_H
  12 #define ACE_LOG_MSG_CALLBACK_H
  13 #include /**/ "ace/pre.h"
  14
  15 #include /**/ "ace/ACE_export.h"
  16
  17 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  18 # pragma once
  19 #endif /* ACE_LACKS_PRAGMA_ONCE */
  20
  21 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  22
  23 class ACE_Log_Record;
  24
  25 /**
  26  * @class ACE_Log_Msg_Callback
  27  *
  28  * @brief An interface class used to get logging callbacks.
  29  *
  30  * Users who are interested in getting the logging messages
  31  * directly, can subclass this interface and override the log()
  32  * method. They must then register their subclass with the
  33  * Log_Msg class and make sure that they turn on the
  34  * ACE_Log_Msg::MSG_CALLBACK flag.
  35  *
  36  * Your log() routine is called with an instance of
  37  * ACE_Log_Record.  From this class, you can get the log
  38  * message, the verbose log message, message type, message
  39  * priority, and so on.
  40  *
  41  * Remember that there is one Log_Msg object per thread.
  42  * Therefore, you may need to register your callback object with
  43  * many ACE_Log_Msg objects (and have the correct
  44  * synchronization in the log() method) or have a separate
  45  * callback object per Log_Msg object.  Moreover,
  46  * ACE_Log_Msg_Callbacks are not inherited when a new thread
  47  * is spawned because it might have been allocated off of the
  48  * stack of the original thread, in which case all hell would
  49  * break loose...  Therefore, you'll need to reset these in each
  50  * new thread.
  51  */
  52 class ACE_Export ACE_Log_Msg_Callback
  53 {
  54 public:
  55   /// Default constructor
  56   ACE_Log_Msg_Callback () = default;
  57
  58   /// No-op virtual destructor.
  59   virtual ~ACE_Log_Msg_Callback () = default;
  60
  61   /// Callback routine.  This is called when we want to log a message.
  62   /// Since this routine is pure virtual, it must be overwritten by the
  63   /// subclass.
  64   virtual void log (ACE_Log_Record &log_record) = 0;
  65 };
  66
  67 ACE_END_VERSIONED_NAMESPACE_DECL
  68
  69 #include /**/ "ace/post.h"
  70 #endif /* ACE_LOG_MSG_CALLBACK_H */