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Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- From: "Carlos O'Donell" <carlos at systemhalted dot org>
- To: Andreas Jaeger <aj at suse dot com>
- Cc: libc-alpha <libc-alpha at sourceware dot org>
- Date: Wed, 17 Apr 2013 14:49:18 -0700
- Subject: Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- References: <513FE49D dot 3050406 at redhat dot com> <Pine dot LNX dot 4 dot 64 dot 1303131610540 dot 19781 at digraph dot polyomino dot org dot uk> <51526E77 dot 4040801 at redhat dot com> <Pine dot LNX dot 4 dot 64 dot 1303271431550 dot 23096 at digraph dot polyomino dot org dot uk> <5154668A dot 6000700 at redhat dot com> <5160465E dot 8060400 at redhat dot com> <20130408210918 dot D97632C074 at topped-with-meat dot com> <51634DE2 dot 1060109 at redhat dot com> <20130408231128 dot DA09C2C0A2 at topped-with-meat dot com> <5163516D dot 1060705 at archlinux dot org> <516805F1 dot 2090504 at redhat dot com> <516D9093 dot 1070705 at redhat dot com> <20130416204733 dot E8EA32C07E at topped-with-meat dot com> <516EE131 dot 1090808 at redhat dot com> <516EF42F dot 8010601 at suse dot com> <m2wqs1szso dot fsf at igel dot home> <516EFFB5 dot 3020206 at suse dot com>
On Wed, Apr 17, 2013 at 1:01 PM, Andreas Jaeger <aj@suse.com> wrote:
>>>> What do you prefer?
>>>>
>>>> CFLAGS='-O2 -march=i686' ./configure ...
>>>>
>>>> or
>>>>
>>>> ./configure ... CFLAGS='-O2 -march=i686'
>>>
>>>
>>> Definitely not "./configure", let's not build in the source directory.
Sorry, that was a typo, it should have been /path/to/src/configure.
e.g.
http://sourceware.org/glibc/wiki/Testing/Builds
>>> My preference is the first one,
That's the same as setting an environment variable and what Roland
wanted to avoid.
>>
>> But the latter works better.
The latter is passing options to configure.
> Could you enlighten me why? If it indeed works better, I'll change my preference ;)
Exactly, I also wanted to be enlightened.
Roland said that in the past, when you changed the configure file, and
re-ran make, that the re-configuration which runs via config.status
might not run in the same shell and thus might not run with the same
set of env vars specified, and thus you would change your compilation
settings by accident (correct me if I'm wrong Roland).
In modern autoconf this is not the case. The config.status encodes CC,
CFLAGS, CPPFLAGS, CXX, CXXFLAGS as options to re-configuation.
e.g.
ac_cs_config="'--with-headers=/home/carlos/install-linux/include'
'--prefix=/usr' '--enable-add-ons=nptl,ports' 'CC=gcc' 'CFLAGS=-g -O3'
'CPPFLAGS=-g -O3' 'CXX=g++' 'CXXFLAGS=-g -O3'"
When I use env vars, or configure parameters, the config.status is
identical and thus all future reconfigurations and builds are
consistently using the same options.
Therefore I do not think we need to avoid using env vars during
configure, however, it's probably best practice to pass options on the
command line to configure.
Cheers,
Carlos.
- References:
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.
- Re: [PATCH] Disable building with i386-*, -march=i386 or -mcpu=i386.