Re: required memchr behavior

[Jim Meyering]

Bruno Haible wrote:
> Eric Blake wrote:
>> > I don't think it is a bug. memchr could also be implemented by doing
>> > a backwards search and still be conforming to ISO C99 and POSIX:
>>
>> The Austin Group disagrees with you.  Here is the results from the meeting
>> yesterday
>> (https://www.opengroup.org/sophocles/show_mail.tpl?CALLER=index.tpl&source=L&listname=austin-group-l&id=12144):
>
> Thanks for bringing up the issue. I'm glad that we can now expect as much
> from memchr() as from strlen(). It's easier to fix the one or two buggy
> implementations of memchr() out there [1][2][3] than to review all uses, in
> strstr, vasnprintf, and many more.
>
>> But as there are systems in the wild with the broken implementation, we
>> should probably start worrying about replacing the buggy memchr
>> implementations.
>
> As a first step, let me add a test to test-memchr. Let's see whether we
> get some reports about it. - Probably we also should undeprecate 'memchr',
> so that its unit test gets included into m4, gettext, coreutils, etc.?

Thanks, yes.

Along those lines, I've done the following in coreutils,
though this causes no change in generated code.

>From 25a6d1b88acec2d18eb23e4ab8abed3b84ca6455 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sun, 31 May 2009 15:18:16 +0200
Subject: [PATCH] build: no longer list gnulib's "memchr" module as obsolete

* bootstrap.conf (obsolete_gnulib_modules): Remove memchr from
the list, now that it fixes a problem in some modern C libraries.
(gnulib_modules): Add it here.
---
 bootstrap.conf |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/bootstrap.conf b/bootstrap.conf
index d34e908..6671027 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -27,7 +27,6 @@ avoided_gnulib_modules='
 # but leave them in for now to minimize changes.
 obsolete_gnulib_modules='
   atexit
-  memchr
   memcmp
   memcpy
   memmove
@@ -141,6 +140,7 @@ gnulib_modules="
   mbsalign
   mbswidth
   memcasecmp
+  memchr
   memcmp2
   mempcpy
   memrchr
--
1.6.3.1.279.gd4bf4