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From: Nicolas Schier <nicolas@fjasle.eu>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v3 3/5] kbuild: add read-file macro
Date: Sat, 10 Dec 2022 22:02:48 +0100	[thread overview]
Message-ID: <Y5Tz+MBfYMVkqAn3@fjasle.eu> (raw)
In-Reply-To: <CAK7LNAQbGaXDRzeByOcJhMX4y-ShA6Qtpcqhr4gNZ5t8vX-PPw@mail.gmail.com>

On Sat, Dec 10, 2022 at 11:10:12PM +0900 Masahiro Yamada wrote:
> On Thu, Dec 8, 2022 at 1:25 AM Alexander Lobakin
> <alexandr.lobakin@intel.com> wrote:
> >
> > From: Alexander Lobakin <alexandr.lobakin@intel.com>
> > Date: Wed, 7 Dec 2022 16:40:44 +0100
> >
> > > From: Masahiro Yamada <masahiroy@kernel.org>
> > > Date: Sun, 27 Nov 2022 07:56:22 +0900
> > >
> > > > Since GNU Make 4.2, $(file ...) supports the read operater '<', which
> > > > is useful to read a file without forking any process. No warning is
> > > > shown even if the input file is missing.
> >
> > [...]
> >
> > > Great stuff. Used it in my upcoming series to simplify things, works
> > > as expected.
> > >
> > > sed-syms = $(subst $(space),\|,$(foreach file,$(sym-files-y),$(call read-file,$(file))))
> > >
> > > The only thing that came to my mind while I was implementing the
> > > oneliner above: maybe add ability to read multiple files? For now,
> > > I used a foreach, could it be somehow incorporated into read-file
> > > already?
> >
> > Oh, nevermind. This one also works:
> >
> > sed-syms = $(subst $(space),\|,$(call read-file,$(sym-files-y)))
> >
> > So I believe read-file works for an arbitrary number of files.
> 
> 
> 
> Really?
> 
> 
> In my understanding, $(call read-file, foo bar) reads a single file "foo bar".
> (a space in the file name).

yes, except for make < 4.2, due to:

read-file = $(shell cat $1 2>/dev/null)


  reply	other threads:[~2022-12-10 21:03 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-26 22:56 [PATCH v3 1/5] kbuild: add test-{le,ge,lt,gt} macros Masahiro Yamada
2022-11-26 22:56 ` [PATCH v3 2/5] kbuild: implement {gcc,clang}-min-version only with built-in functions Masahiro Yamada
2022-11-26 22:56 ` [PATCH v3 3/5] kbuild: add read-file macro Masahiro Yamada
2022-12-07 15:40   ` Alexander Lobakin
2022-12-07 16:22     ` Alexander Lobakin
2022-12-10 14:10       ` Masahiro Yamada
2022-12-10 21:02         ` Nicolas Schier [this message]
2022-12-12 14:37           ` Alexander Lobakin
2022-11-26 22:56 ` [PATCH v3 4/5] kconfig: refactor Makefile to reduce process forks Masahiro Yamada
2022-11-26 22:56 ` [PATCH v3 5/5] kbuild: check Make version Masahiro Yamada

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