Writing Monitors for the Event Monitoring Service (December 1999)

44 Chapter2

The EMS Application Programming Interface (API)

Function Descriptions

In order to minimize potential timeouts when communicating with a

monitor, call rm_monitor_start and rm_get_next_event (in that order)

as soon as possible in your monitor code.

The following events will cause rm_get_next_event() to return:

• A message arrives from the Registrar. This message will be a

Subclass Request or Monitor Request.

• A timer pops, indicating that the EMS API needs an update from the

resource monitor about a resource value.

• A timer pops, indicating that there has been no activity associated

with this resource monitor for a lengthy period (60 minutes), and that

the resource monitor may terminate.

• A message has arrived from some source other than the EMS API.

This select event applies only to resource monitors that use the

select(2) parameters.

• A timer pops, indicating that the time interval speciﬁed by the

resource monitor has expired without any messages arriving. This

timeout event applies only to resource monitors that use the

select(2) parameters.

• A monitor request is unregistered. The resource monitor is informed

when a monitor request is unregistered, although in general no action

is necessary.