Re: Understanding Pattern Rules

[Paul Smith]

On Tue, 2015-05-05 at 07:49 -0700, address@hidden wrote:
> file.out: %.cached
>         cat $^ > file.out

This is not a pattern rule.  A pattern rule must have a pattern match
(the "%") in the TARGET, because it matches any of a set of targets.
Having a pattern in the prerequisite is optional, but there must be one
in the target, or else it's an explicit rule... and thus it depends on
the explicit prerequisite named, literally, '%.cached'.

To make this a pattern rule you'd need to write:

  %.out : %.cached
          cat $^ > $@

or similar.