EMS Manual

Retrieving Event Messages Programmatically

EMS Manual—426909-005

4-4

Changing the Environment

Your management application can dynamically control its distributor environment—the

source (or sources) of event messages, the log file position, and the filter and its

parameters—by using the distributor’s subsystem programmatic interface (SPI). To

control the distributor environment, use the ADD, ALTER, DELETE, and REPLACE

commands described in Section 17, Distributor Commands and Responses.

Filters and Filter Parameters

This command message example uses the non-object-oriented interface, which uses a

maximum of one filter per distributor. For distributors that require multiple filters, the

alternative object-oriented ADD, DELETE, or REPLACE command messages let you

add or delete filters or replace the current filter or return to the default filter (pass all

event messages). These commands also let you pass parameters to a filter when you

load it or change the parameter values the current filter is using.

To load a filter, pass the distributor the name of the file containing the compiled filter

specification. Use the token ZEMS^TKN^FILTERFILE to specify the file name.

For example, to construct the appropriate command message to load a filter stored in a

file called FCRIT and send it to the distributor using the WRITEREAD procedure (the

distributor will contain only this filter):

! Initialize buffer for distributor CONTROL command message

IF (error := SSINIT(spibuffer,

ZEMS^VAL^BUFLEN,

ZEMS^VAL^SSID,

ZSPI^VAL^CMDHDR,

ZEMS^CMD^CONTROL)) THEN ...

! Get external file name to use as token value

sbuf ':=' ["FCRIT", 0];

CALL FNAMEEXPAND(sbuf, filter^file^name,

my^file^defaults);

! Place token with token value in spibuffer

IF (error := SSPUTTKN(spibuffer,

ZEMS^TKN^FILTERFILE,

filter^file^name)) THEN ...

! Determine how many bytes of spibuffer have been used

spi^error := SSGETTKN(spibuffer,

ZSPI^TKN^USEDLEN,

buffer^length);

! Handle any error from SPI procedure

IF spi^error <> ZSPI^ERR^OK THEN ...

! And send the command message

CALL WRITEREAD(fnum,

spibuffer,

buffer^length,