// Some Implementation File
void * refToSelf;
int cCallback(void *userPtr)
{
   DoorManager *self = (id)userPtr;
//   objc_msgSend (self, @selector(cancelAllTasks), nil);   
    [self cancelAllTasks];
   NSLog(@"Phidget Sleep call back\n");
   return 0;
}
implementation DoorManager

#pragma mark Init / Final
-(id) init {      
   if (self=[super init]) {
// Handle sleeping      
      CPhidget_set_OnWillSleep_Handler(cCallback,self);
      refToSelf = self;
   }
   return self;
}
...
-(BOOL) cancelAllTasks {   
   [DBManager logStr:@"Close all doors called via Phidget Library"];
   return [doorOpener cancelAllTasks];
}
@end

// Next File DoorOpener.m

-(BOOL) cancelAllTasks {
   
   BOOL loopStatus=YES;
       status    =YES;
   
   [DBManager logStr:[NSMutableString stringWithFormat:@"Canceling all tasks(%d)",[fifoOfTimers count] ]];         
   NSArray *temp = [NSArray arrayWithArray: fifoOfTimers];   
   for (NSMutableDictionary  *task in temp) {
      loopStatus =  [self cancelTask:task];
      status = (loopStatus == NO) ? loopStatus : status;
      [fifoOfTimers removeObject:task];
//       [NSThread sleepForTimeInterval:3];
   }

    return status;
}

// Cancel closes the door by setting the relay off and then cancels the timer
// Returns to the caller a boolean status of YES if phidget returned EPHIDGET_OK.
-(BOOL ) cancelTask : (NSDictionary *) dict {
   int index;
   RelayCard *rc;
   NSNumber  *taskIdNSNum ;
   
   index      = [ [dict objectForKey:@"theRelayIndex" ] intValue];
   rc         =   [dict objectForKey:@"theRelayCard"  ];
   taskIdNSNum =   [dict objectForKey:@"taskId"      ];
   id < NSObject,DoorOpenerDelegate>  delegateId = [dict objectForKey:@"delegateId"   ];
      
   int resultCode = [rc setRelaysIndex:index state:NO];
   status = YES;
   if( resultCode != EPHIDGET_OK ) {
      [DBManager logStr:[NSMutableString stringWithFormat:@"Task(%@) Cancel Completion Failed with Result:%@",taskIdNSNum,[rc lastErrorMsg]]];            
      status = NO;      
   } else {
      [DBManager logStr:[NSMutableString stringWithFormat:@"Task(%@) Cancel Completion Success with Result:%@",taskIdNSNum,[rc lastErrorMsg]]];            
   }
   [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(timerHasExpired:) object:dict];
   if (delegateId && [delegateId respondsToSelector:@selector(taskCompleted:taskId:)]) {
      [delegateId taskCompleted:status taskId:[taskIdNSNum intValue]];      
   } else {
      if (delegateId && [delegateId respondsToSelector:@selector(taskCompleted:)]) {
         //         [delegate taskCompleted:status];      
      }
   }   
   return status;
}

// File relayCard.m
-(int) setRelaysIndex:(int) index state:(BOOL) state {
   
   if(  hwIsSimulated )
      return EPHIDGET_OK;

   resultCode = CPhidgetInterfaceKit_setOutputState(ifkit, index , state);
   if( resultCode != EPHIDGET_OK ) {      
      CPhidget_getErrorDescription(resultCode,&lastErrorResultStr);
//      NSLog(@"Failed to set card's relay index(%d) with serial number%d, its state is unknown",index,serialNumber); // Caller should log the error
   }
   relayStates[index] = state;
   return resultCode;
}