ViewPoint Manual

Customizing ViewPoint
ViewPoint Manual—426801-001
6-10
Filter Parameters for Dynamic Configuration
Filter Parameters for Dynamic Configuration
You can specify filter parameter values that dynamically change the default alternate-
events filter (FLTRALT). Enter these values on page 2 of the Alternate Event
Configuration screen. (Refer to the description of the Event Configuration screen in
Section 3, Definition of ViewPoint Screens
.) When you use this screen for alternate
events, it displays alterable fields that show the current parameter values and allows you
to enter new values. These parameters allow filtering criteria to be changed dynamically
without requiring filter compilation or reconfiguration of ViewPoint.
A SELECT-DISCARD operand in the filter determines what action is to be taken on
qualifying events. For example, if the operator chose SELECTED and then specified
Subsystem ID as TANDEM.Pathway and Event Number as 3001, only Pathway events
numbered 3001 would pass the filter. Conversely, if you chose DISCARDED and then
specified the same parameter values, all events except Pathway events numbered 3001
would pass the filter.
The parameters allow the operator to select or discard events based on system name,
subsystem ID, event number, CPU, process ID, or the event text. All the parameter
values except event text are compared to the corresponding values of the process
reporting the event. Event text is compared with event text produced by EMSTEXT.
The entire event text (less header text) is used in the comparison. The parameter value
provided for event text might contain an asterisk (*) or a question mark (?). A question
mark (?) matches any one character; an asterisk (*) matches zero or more consecutive
characters.
You can also alter the default alternate-events filter (FLTRALT)—or write a new filter—
to change the logic or supply conditions that test for custom parameters. The operator
specifies the custom parameters on the same screen as the other filter parameters. As
many as four custom parameter values can be specified. Each value is one of the
following types: file, string, or number (a 64-bit signed integer). These types
correspond to the basic types supported by the EMS filter language. Specified values
are passed to the filter in the following tokens: ZVPT^FLTR^CUSTOM^FILE,
ZVPT^FLTR^CUSTOM^STRING, or ZVPT^FLTR^CUSTOM^NUMBER. Multiple
instances of a single value type are represented as multiple-instance parameter tokens;
indexes are used to refer to each instance.
If you create your own filter, it is not necessary for you to use the parameters specified
on the Alternate Event Configuration screen. The default filter (FLTRALT) uses any
noncustom parameters that are supplied, but you can change the configuration to use a
filter that does not recognize these parameters. No warning will be issued at the time
you process the screen.
Be aware that if you specify any of the custom parameter values and you have changed
the configuration to use a filter that does not recognize these parameters, you probably
will receive the error message “Error returned from EMS distributor:” (see error
message 0315 in Appendix B, Error Messages
).
Conversely, all parameter values are optional. If any of the parameter values are not
specified (left blank), then the corresponding parameter token is not passed to the filter.
If you want to use custom parameters, use the default filter shown in Figure 6-2 and
include your custom source code at the location shown on page 4 of this figure.