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Re: Implement Check on Input Values
From: |
David Boyce |
Subject: |
Re: Implement Check on Input Values |
Date: |
Mon, 8 Aug 2011 15:50:19 -0400 |
On Mon, Aug 8, 2011 at 3:15 PM, Lane Schwartz <address@hidden> wrote:
> Why is it bad to do mkdir in a recipe? I do things like this all the
> time, and I've never had problems when using -j
>
> foo/bar: | foo
> ...do something...
>
> foo:
> mkdir -p $@
Sorry, you're quite right and I expressed myself badly. A
single-purpose recipe to create a directory, relying on an order-only
prerequisite, is safe and in fact elegant. It's combining mkdirs into
recipes which do other things that's bad. E.g.:
$(objdir)/%.o: %.c
@mkdir $(@D)
$(CC) ...
Which is really just a variant of one of Paul's rules. Paraphrased -
tell make exactly what you plan to create, and don't create anything
you didn't tell it about.
-David Boyce
Re: Implement Check on Input Values, Lane Schwartz, 2011/08/08