The fax server sends a WM_FAX_MESSAGE message to a window to notify a fax client application when asynchronous events occur within the fax server. The application will receive messages only if it calls the FaxInitializeEventQueue function and registers to receive events as notification messages.

The message definition provided here is for explanation only; it is not present in any standard header file.



Specifies the event identifier of the message.

To determine if an event is a fax event, subtract the value of the application's base event from the value of this parameter. If the result is between zero and FEI_NEVENTS, the window can process the event as a fax event. For more information, see the following Remarks section.


Value of wParam. Specifies the device identifier to associate with fax events that are related to devices.


Value of lParam. Specifies the job identifier to associate with fax events that are related to fax jobs.

Return value

An application returns zero if it processes this message.


The fax server sends notification messages to the window specified by the hWnd parameter to the FaxInitializeEventQueue function.

A window can process a message as a fax message if the message falls between the range of the client application's base window message and the base window message + FEI_NEVENTS. An application specifies the base window message using the MessageStart parameter of the FaxInitializeEventQueue function. A WM_FAX_MESSAGE is an event that falls within the range of MessageStart to MessageStart + FEI_NEVENTS.

For a list of the asynchronous events that can occur within the fax server, see FAX_EVENT. For more information, see Enabling an Application to Receive Notifications of Fax Events.


Minimum supported client
Windows 2000 Professional [desktop apps only]
Minimum supported server
Windows 2000 Server [desktop apps only]

See also

Fax Service Client API for Windows 2000