This statement applies the specified main window filter to the currently active files and saves the result of the filter to a specified track variable. The track variable will be set to 1 if the associated file was matched by the filter, otherwise 0. This is an extremely efficient means of testing a number of conditions.
Note that only the criteria logic in the filter is used. The function to be applied (select, hide, close) is ignored. In order to be used by this statement, a filter must have been saved. ie. it has to be named.
The filter field may contain any of the escape sequences described in Escape Sequences. If a specified filter does not exist at runtime it is a fatal error.
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