TACL Reference Manual

Built-In Functions and Variables
HP NonStop TACL Reference Manual—429513-018
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#FILTER Built-In Function
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Only the most recent #FILTER in a routine has any effect. If a routine that contains
a filter list calls another routine that also contains a filter list, the list in the called
routine becomes active. When control is returned from that routine, the filter list in
the calling routine resumes active status. If a routine contains more than one
#FILTER function call, the latest list supersedes all previous lists.
•
When an exception occurs, if the current routine has no exception handler, TACL
automatically exits that routine and pops you out of routines until it finds a #FILTER
for that exception and reinvokes the routine containing the #FILTER. If TACL finds
no such routine, it performs its normal exception handling: it resets frames and
results and, if the exception is the predefined _ERROR exception, it displays an
error message.
•
To determine why an exception handler was invoked, use the #EXCEPTION built-
in function. To raise an exception, use the #RAISE built-in function.
Example
This example shows a #FILTER call that lists two exceptions:
#FILTER _ERROR userex
For examples showing the use of #FILTER with exception handlers, refer to the TACL
Programming Guide.