The FindFirstPrinterChangeNotification function creates a change notification object and returns a handle to the object. You can then use this handle in a call to one of the wait functions to monitor changes to the printer or print server.
The FindFirstPrinterChangeNotification call specifies the type of changes to be monitored. You can specify a set of conditions to monitor for changes, a set of printer information fields to monitor, or both.
A wait operation on the change notification handle succeeds when one of the specified changes occurs in the specified printer or print server. You then call the FindNextPrinterChangeNotification function to retrieve information about the change, and to reset the change notification object for use in the next wait operation.
HANDLE FindFirstPrinterChangeNotification( _In_ HANDLE hPrinter, DWORD fdwFilter, DWORD fdwOptions, _In_opt_ LPVOID pPrinterNotifyOptions );
- hPrinter [in]
The conditions that will cause the change notification object to enter a signaled state. A change notification occurs when one or more of the specified conditions are met. The fdwFilter parameter can be zero if pPrinterNotifyOptions is non-NULL.
This parameter can be one or more of the following values.
For descriptions of the more specific flags in the preceding table, see the FindNextPrinterChangeNotification function.
The flag that determines the category of printers for which notifications will work. When this flag is set to PRINTER_NOTIFY_CATEGORY_ALL, then FindFirstPrinterChangeNotification will work for 2D and 3D printers. When this flag is set to zero (0), FindFirstPrinterChangeNotification will only work for 2D printers.
- pPrinterNotifyOptions [in, optional]
A pointer to a PRINTER_NOTIFY_OPTIONS structure. The pTypes member of this structure is an array of one or more PRINTER_NOTIFY_OPTIONS_TYPE structures, each of which specifies a printer information field to monitor. A change notification occurs when one or more of the specified fields changes. When a change occurs, the FindNextPrinterChangeNotification function can retrieve the new printer information. This parameter can be NULL if fdwFilter is nonzero.
For a list of fields that can be monitored, see PRINTER_NOTIFY_OPTIONS_TYPE.
If the function succeeds, the return value is a handle to a change notification object associated with the specified printer or print server.
If the function fails, the return value is INVALID_HANDLE_VALUE.
Note This is a blocking or synchronous function and might not return immediately. How quickly this function returns depends on run-time factors such as network status, print server configuration, and printer driver implementation—factors that are difficult to predict when writing an application. Calling this function from a thread that manages interaction with the user interface could make the application appear to be unresponsive.
To monitor a printer or print server, call the FindFirstPrinterChangeNotification function, then use the returned change notification object handle in a call to one of the wait functions. A wait operation on a change notification object is satisfied when the change notification object enters the signaled state. The system signals the object when one or more of the changes specified by fdwFilter or pPrinterNotifyOptions occurs in the monitored printer or print server.
When you call FindFirstPrinterChangeNotification, either fdwFilter must be nonzero or pPrinterNotifyOptions must be non-NULL. If both are specified, notifications will occur for both.
When a wait operation on a printer change notification object is satisfied, call the FindNextPrinterChangeNotification function to determine the cause of the notification. For a condition specified by fdwFilter, FindNextPrinterChangeNotification reports the condition or conditions that changed. For a printer information field specified by pPrinterNotifyOptions, FindNextPrinterChangeNotification reports the field or fields that changed as well as the new information for these fields. FindNextPrinterChangeNotification also resets the change notification object to the nonsignaled state so you can use it in another wait operation to continue monitoring the printer or print server.
With one exception, do not call the FindNextPrinterChangeNotification function if the change notification object is not in the signaled state. If the wait function returns the value WAIT_TIMEOUT, the change object is not in the signaled state. Call the FindNextPrinterChangeNotification function only if the wait function succeeds without timing out. The exception is when FindNextPrinterChangeNotification is called with the PRINTER_NOTIFY_OPTIONS_REFRESH bit set in the pPrinterNotifyOptions parameter.
When you no longer need the change notification object, close it by calling the FindClosePrinterChangeNotification function.
Callers of FindFirstPrinterChangeNotification must ensure that the printer handle passed into FindFirstPrinterChangeNotification remains valid until FindClosePrinterChangeNotification is called. If the printer handle is closed before the printer change notification handle, further notifications will fail to be delivered.
FindFirstPrinterChangeNotification will not send change notifications for 3D printers to server handles.
Note In Windows XP with Service Pack 2 (SP2) and later, the Internet Connection Firewall (ICF) blocks printer ports by default, but an exception for File and Print Sharing can be enabled. If a user makes a printer connection to another machine, and the exception is not enabled, then the user will not receive printer change notifications from the server. A machine admin will have to enable exception.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|
- Print Spooler API Functions