win32 service crashing in vista

[Subrat Patnaik]

hi, i am having a service running in vista. it captures the information of the USB devices that are being used in the system. i am registering for device notification when starting the service using the RegisterDeviceNotification API, however the service is crashing when i am calling UnregisterDeviceNotification API Pasting the piece of code below....if needed i would also give the values out of debugging. please could i get some help or hints as to why my service is crashing when i am calling UnregisterDeviceNotification ?

DWORD WINAPI service_ctrl(DWORD dwCtrlCode,DWORD dwEventType, LPVOID lpEventData, LPVOID lpContext)
{
PDEV_BROADCAST_HDR head = (PDEV_BROADCAST_HDR )lpEventData;

switch (dwCtrlCode) 
{
case SERVICE\_CONTROL\_DEVICEEVENT: 
	if (dwEventType == DBT\_DEVICEQUERYREMOVE)
	{
		if(head->dbch\_devicetype == DBT\_DEVTYP\_HANDLE)
		{	
			PDEV\_BROADCAST\_HANDLE  db = (PDEV\_BROADCAST\_HANDLE) head;
			DebugLog("Remove Query");


			ht\_pIter = handleThread.find(db->dbch\_handle);
			if ( ht\_pIter == handleThread.end( ) )
				DebugLog("cannot find Thread ID using Handle Value ");
			else
			{

				killThreadFunc(ht\_pIter->second.threadHandle,ht\_pIter->second.threadID);
				DebugLog("after killThreadFunc");
				if(!CloseHandle(db->dbch\_handle))
				{

					DebugLog("Problem in Closing Directory Handle.");
				}

				char error\[50\] = {0};
				if(!UnregisterDeviceNotification(\*ht\_pIter->second.devNotify))
				{
					DebugLog("Problem in Unregistering Device notification.");
					sprintf(error,"Error Code returned is %d",GetLastError());
					DebugLog(error);					

				}

				handleThread.erase(db->dbch\_handle);

				//SetEvent(hLogTrigger);
				DebugLog("Thread Terminate Successful");
			}

		}
		return NO\_ERROR;
	}//end if DEVICEQUERYREMOVE
	break;
}

}

[Aescleal]

Why the dereference of the structure field? *ht_pIter->second.devNotify looks a bit suspect - generally you deal with handles not pointers to handles. Cheers, Ash