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Re: PATH_MAX constant expression
From: |
Jim Meyering |
Subject: |
Re: PATH_MAX constant expression |
Date: |
Tue, 21 Jun 2011 06:51:46 +0200 |
Eric Blake wrote:
> On 06/20/2011 04:34 PM, Bruno Haible wrote:
>> I find it reasonable to use "#ifdef PATH_MAX" in front of every use of
>> PATH_MAX, like POSIX requires.
>>
>>> But later on in test-getcwd, we have code
>>> that does #ifndef PATH_MAX, which is no longer reachable because of our
>>> guarantee that PATH_MAX is always defined in pathmax.h.
>>
>> No, we don't want to guarantee a PATH_MAX on GNU/Hurd.
>>
>> Here's a proposed patch:
>>
>>
>> 2011-06-20 Bruno Haible <address@hidden>
>>
>> pathmax: Never define PATH_MAX to a non-constant expression.
>> * lib/pathmax.h (PATH_MAX): Don't define in terms of pathconf.
>> * m4/pathmax.m4 (gl_PATHMAX): Don't test for pathconf.
>
> Looks okay to me, but let's wait to see if anyone else also has an
> opinion. Let's also enhance doc/posix-headers/limits.texi to mention
> the pathmax module and its (new) semantics of not interfering with Hurd.
coreutils has few remaining uses of PATH_MAX, but they do expect
pathmax.h to define it unconditionally, and from what I recall,
it has always worked that way. Thus, changing it *not* to define
PATH_MAX on the Hurd would cause trouble.
In any case, it looks like your patch is ok, since the combination
of these two blocks ensures that PATH_MAX *is* always defined:
# ifndef _POSIX_PATH_MAX
# define _POSIX_PATH_MAX 256
# endif
# ifndef PATH_MAX
# define PATH_MAX _POSIX_PATH_MAX
# endif
- PATH_MAX on HP-UX, Bruno Haible, 2011/06/18
- Re: PATH_MAX on HP-UX, Eric Blake, 2011/06/20
- Re: PATH_MAX constant expression, Bruno Haible, 2011/06/20
- Re: PATH_MAX constant expression, Eric Blake, 2011/06/20
- Re: PATH_MAX constant expression,
Jim Meyering <=
- Re: PATH_MAX constant expression, Eric Blake, 2011/06/21
- Re: PATH_MAX constant expression, Jim Meyering, 2011/06/21
- Re: PATH_MAX constant expression, Bruno Haible, 2011/06/23
- Re: PATH_MAX constant expression, Jim Meyering, 2011/06/24
- Re: PATH_MAX constant expression, James Youngman, 2011/06/21
- Re: PATH_MAX constant expression, Eric Blake, 2011/06/21