Re: Using LS/LE (was: [PATCH v4 2/4] man/man5/tunables.conf: Document system-wide tunables config)

[Alejandro Colomar <alx@kernel.org>]

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Hi Larry,

> Date: 2026-08-28 22:50:50-0400
> From: Larry Kollar <larry.kollar@icloud.com>
>
> 
> Alejandro Colomar <alx@kernel.org> wrote:
> 
> > I believe that a set of makefiles that would handle all of the targets
> > of a project like groff wouldn't take much more than that.  It might be
> > a few hundred kB.  If it's well organized, it can be maintainable.
> > 
> > Because the makefile language is so simple, bugs are easy to spot and
> > fix, compared to autotools (possibly automake, but I can't distinguish
> > them enough).
> 
> I don’t know. Can a Makefile check for the presence of certain libraries
> or other apps and fail gracefully (by which I mean exiting with a message
> like “You need app X, plus libraries Y and Z, installed to successfully
> compile this.”)? That’s one of the things that “makes" me appreciate taking
> that extra step of typing `.configure` before make.

Yes, it can.  Here's a trivial test for that:

	alx@devuan:~/tmp/testlib$ cat Makefile 
	HAS_LIBFOO := $(shell find /usr/include/foo.h >/dev/null && echo yes || echo no)

	ifeq ($(HAS_LIBFOO),no)
	  $(error You need library FOO installed to successfully compile this.)
	endif

	all:
		echo Done
	alx@devuan:~/tmp/testlib$ make
	find: ‘/usr/include/foo.h’: No such file or directory
	Makefile:4: *** You need library FOO installed to successfully compile this..  Stop.

You may of course write more complex tests if you need.  Anything that
you can do with a shell script, you can do it with a Makefile.

That said, I personally prefer to fail compilation due to missing header
files.  It's simpler, and there's not much difference.  After all, if
compilation fails for <foo.h>, it's trivial to run

	$ apt-file find /include/foo.h

But if you want the test, you can have it.


Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es>

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