ServiceNotification Event 94

Applies To: Root

Description

This event is generated in an APL service whenever the Windows Service Control Manager (SCM) requests a change of state. See APL Application as a Service.

The event message reported as the result of ⎕DQ, or supplied as the right argument to your callback function, is a 4-element vector as follows :

[1]	Object	ref or character vector
[2]	Event	'ServiceNotification' or 94
[3]	Action	Integer.
[4]	State	7-element integer vector

For further details, see the on-line documentation for SERVICE_STATE and the function HashDefine in the sample workspace aplservice.

The state of a Windows service is determined by the user and the Windows Service Control Manager (SCM).

When the SCM requests a change of state, the APL interpreter responds by setting its state to the corresponding pending level (SERVICE_STOPPED_PENDING, SERVICE_RUNNING_PENDING or SERVICE_PAUSED_PENDING) and then generates a ServiceNotification event.

It is the responsibility of the APL service to process this event, perform the appropriate application tasks, and then respond (to the SCM) by calling the SetServiceState method to confirm that the service has reached the desired state.