EMS Manual

Compiled Filters
EMS Manual—426909-005
5-27
Declarations
FILTER Declaration
The syntax for declaring a filter:
filter-name
is an identifier.
param
is the qualified name of a parameter token optionally followed by the keyword
REQUIRED or by the keyword OPTIONAL. For the meaning of these keywords,
see Filter Parameters on page 5-29.
SSID ( subsystem-id )
if present, gives the subsystem ID that changes the EMF default subsystem ID
within the filter. If you omit this parameter, the NULL subsystem ID becomes the
EMF default subsystem ID.
variable-decls
if present, is the keyword BOOLEAN, followed by a comma-separated list of
identifiers.
statement
is any filter-language statement.
Considerations

Each Boolean variable is set to FALSE before each event message is filtered.
Therefore, results that must be saved across event messages must be saved in an
application, not in a filter.

You must declare each Boolean variable used.

You must initialize every symbolic subsystem ID that you use in the filter. For
information on initializing subsystem IDs, see The Filter Compiler
on page 5-44
and Example 3
on page 5-28.

You can declare a maximum of 50 Boolean variables.
FILTER filter-name [ ( param [ , param ] ... ) ];
BEGIN [ SSID ( subsystem-id ) ]
[ variable-decls ]
statement [ ; statement ] ...
END