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Re: make -jN runs some rules more than once
From: |
Edward Welbourne |
Subject: |
Re: make -jN runs some rules more than once |
Date: |
Sat, 12 Sep 2015 10:54:54 +0000 |
>> a.gz b.gz:
>> touch a
>> gzip a
>> touch b
>> gzip b
Paule explained (in detail)
> multiple explicit targets are just a shorthand way of writing multiple rules,
... and if you actually want to do two things at the same time, you can
do it, via a phony intermediate:
a.gz b.gz .PHONY: zippem
zippem:
touch a
gzip a
touch b
gzip b
so that both targets get built by zippem the one time it gets run. In
principle, the empty rules to make a.gz from zippem and b.gz from zippem
both get run; but they're both no-ops. This is a somewhat bogus thing
to do, of course, but I'm guessing your original rule was willfully
over-simplified from something where it won't be as bogus ...
Eddy.