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Re: [PATCH 06/13] Installed header hygiene (BZ#20366): Macros used in #if without checking whether they are defined.
- From: Carlos O'Donell <carlos at redhat dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Zack Weinberg <zackw at panix dot com>, libc-alpha at sourceware dot org
- Date: Wed, 21 Sep 2016 14:40:58 -0400
- Subject: Re: [PATCH 06/13] Installed header hygiene (BZ#20366): Macros used in #if without checking whether they are defined.
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On 09/21/2016 02:05 PM, Joseph Myers wrote:
> On Wed, 21 Sep 2016, Carlos O'Donell wrote:
>> At a high level I would expect _LIBC to always be defined as either 0 or 1.
> _LIBC is effectively with external code, because it's used (with #if) in
> code shared by gnulib. So we can't change its semantics like that;
> defining to 0 with installed glibc would break building gnulib.
Isn't that just a normal coordination issue with gnulib?
Changes in GCC routinely break building glibc, either intentional or
In this case there would be a dependency between this glibc version
and the usable versions of gnulib which could be built with that glibc?
I agree that such gratuitous breakage for a weak reason like installed
header hygiene would be a bad idea.
However, I don't think we should avoid the change, but rather coordinate
with gnulib if we ever need it.