PRB: JournalPlayback Hook Can Cause Windows NT to Hang

MORE INFORMATION

Sample Code

   LRESULT CALLBACK JournalPlaybackProc(
       int nCode,
       WPARAM wParam,
       LPARAM lParam)
   {
       static BOOL     fDelay;
       static EVENTMSG event;
       static LRESULT  ticks_delay;
       BOOL            fCallNextHook = FALSE;
       LRESULT         lResult = 0;

       switch( nCode )
       {
           case HC_SKIP:
               fDelay = TRUE;      // <<<< CORRECT PLACE TO RESET fDelay

               // Get the next event from the list. If the routine returns
               // FALSE, then we are done - release the hook.
               if( !GetNextEvent( &event, &ticks_delay ))
                   SetJournalHook( FALSE, NULL );
               break;

           case HC_GETNEXT:
           {
               // Structure information returned from previous GetNextEvent
               // call.
               LPEVENTMSG lpEvent = (LPEVENTMSG) lParam;

               // Set the event
               *lpEvent = event;

               if( fDelay )
               {
                   // Toggle pause variable so that the next call will not
                   // pause. Return the pause length specified by
                   // ticks_delay since this is the first time the event
                   // has been requested.

                   fDelay = FALSE; // <<<< CORRECT PLACE TO CLEAR fDelay
                   return( ticks_delay );
               }
               break;
           }

           case HC_SYSMODALOFF:
                  // System modal dialog is going away. Something was
                  // corrupted.  Windows took care of removing our
                  // JournalPlayback hook, so no need to call
                  // SetJournalHook( FALSE ).

               fCallNextHook = TRUE;
               break;

           case HC_SYSMODALON:
           default:
               // Something is not right here. Let the next hook handle
               // it.

               fCallNextHook = TRUE;
               break;
       }

       // If the event was not processed by our code, call next hook.
          if( fCallNextHook )
              lResult = CallNextHookEx( s_journalHook, nCode, wParam,
                                        lParam    );

       // fDelay = TRUE;           // <<<< WRONG PLACE TO RESET bDelay !!!
       return lResult;
   }