Writing Monitors for the Event Monitoring Service (December 1999)

Chapter 3 95

Creating a Resource Monitor

Processing a Monitor Request Event

A Monitor Request asks the resource monitor whether it is ready to

monitor the resource speciﬁed. If so, the monitor will reply with a

positive Monitor Reply. The Monitor Request Event is speciﬁed by a

return_type of RM_MONITOR_REQUEST_EVENT from

rm_get_next_event().

Replying to Monitor Request Events

To process a monitor request event for your resource monitor, include the

following information.

• Assume success.

• Check that the resource requested is supported.

• Check polling interval.

Asynchronous monitors should:

— only accept a request for polling interval = 0. If a non-zero value is

requested, set RmMonitorReply to RM_POLLING_NOT_SUPPORTED.

— avoid getting update events polled by EMS

— avoid misleading the user that polling is supported (by including

query requests)

Most state monitors should support a minimum polling interval. If

the requested polling interval is less than the minimum, set the

monitor to reply with RM_POLLTIME and set the minimum supported

polling internal in the RmPollingMinimum ﬁeld.

• If appropriate, set RmOVSeverity.

If resource values are an enumeration that represent allor asubset of

the severities deﬁned in the section “Replying to Subclass Events,” set

to RM_OV_ENUMERATION.

• If the monitor needs to track resources for which active monitor

requests exist, check the RmLifeTime options:

— RM_PREVIEW_REGISTER This checks, but does not register

requests.