From: Jeff King <peff@peff.net>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: git discussion list <git@vger.kernel.org>
Subject: Re: Compiling git with -Werror
Date: Fri, 27 Apr 2012 06:07:31 -0400 [thread overview]
Message-ID: <20120427100731.GC19918@sigill.intra.peff.net> (raw)
In-Reply-To: <4F9A6AB0.1050504@alum.mit.edu>
On Fri, Apr 27, 2012 at 11:45:20AM +0200, Michael Haggerty wrote:
> I like to develop with errors and warnings turned up as strict as
> possible. For example, I would like to use
>
> CFLAGS="-g -O2 -Wall -Werror -Wdeclaration-after-statement"
That's more or less how I compile git.
> I thought this would be as simple as
>
> git clean -fdx
> make configure
> ./configure CFLAGS="-g -O2 -Wall -Werror -Wdeclaration-after-statement"
I don't use our autoconf at all, though. I put settings like that into
config.mak, which gets sourced by the Makefile (right after
config.mak.autogen, which is what configure produces).
> The cause of the problem is that the CFLAGS variable is used by
> ./configure when it is running its tests, and some of the tests don't
> work correctly (they produce results that are not correct for the
> platform) when run with the strict CFLAGS.
> [...]
> Is there some other mechanism to set strict CFLAGS parameters for the
> build without confusing ./configure?
Try putting "CFLAGS += -Werror" in config.mak.
> Is this a bug in how the git project is using autoconf?
>
> Is it a bug in autoconf itself?
I think autoconf. Our configure input is just using
AC_CHECK_FUNC(strtok_r) to generate the test. Which would mean that
it's a bad interaction of autoconf's code and your CFLAGS. So I would be
surprised if other packages didn't have similar problems.
And indeed, googling for 'autoconf cflags "-Werror"' turns up:
http://lists.gnu.org/archive/html/bug-autoconf/2012-03/msg00070.html
Summary: don't do that. We could add a special option to turn on
warnings, but given how easy the config.mak trick above is, I don't know
that it's necessary.
-Peff
prev parent reply other threads:[~2012-04-27 10:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 9:45 Compiling git with -Werror Michael Haggerty
2012-04-27 9:58 ` Thomas Rast
2012-04-27 10:07 ` Jeff King [this message]
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