Writing Monitors for the Event Monitoring Service (December 1999)

42 Chapter2

The EMS Application Programming Interface (API)

Function Descriptions

Table 2-7 rm_select_type

select_data

Parameter Fields

Field Name Type Description

exceptfds fd_set On input speciﬁes the ﬁle descriptors to be

checked for having error conditions pending, and

on output indicates which ﬁle descriptors have

error conditions pending. The EMS API will

automatically add the ﬁle descriptors of all sockets

it uses to communicate with the Registrar to this

list and remove them before returning the

exceptfds structure.

Note: Messages from the EMS API have a lower

priority than other messages. They will be

processed only when the ﬁle descriptors in

readfds, writefds, and exceptfds do not

contain pending messages.

Resource Monitors that do not need to use this

ﬁeld should set it to all zeros. See select(2) for

more information.

num_fds int Upon return, this value speciﬁes how many ﬁle

descriptors are marked in the ﬁle descriptor ﬁelds.

See select(2) for more information.

readfds fd_set On input speciﬁes the ﬁle descriptors to be

checked for being ready to read, and on output

indicates which ﬁle descriptors are ready to read.

The EMS API will automatically add the ﬁle

descriptors of all sockets it uses to communicate

with the Registrar to this list and remove them

before returning the readfds structure.