Обсуждение: more POSIX 2008 cleanup: strnlen(), rindex()

It has previously been established that POSIX 2008 is the baseline for 
PostgreSQL code (modulo Windows).  Looking through the POSIX 2008 
changes, I found a few more things we can clean up with respect to that.

The first patch removes the configure checks for strnlen(), since that 
is now required, and I see that all buildfarm members support.  There 
was some discussion in the commit messages that added these checks 
(e.g., commit 8a241792f96) that suggests it was once required, but I did 
not find any information about which platforms were affected then.  But 
that's 8 years ago now, so I think it might be obsolete.

The second patch replaces the single remaining use of rindex() with the 
equivalent strrchr().  rindex() has been removed from POSIX.

On Sat, 3 Jan 2026 at 10:52, Peter Eisentraut <peter@eisentraut.org> wrote:
> It has previously been established that POSIX 2008 is the baseline for
> PostgreSQL code (modulo Windows).  Looking through the POSIX 2008
> changes, I found a few more things we can clean up with respect to that.

Both changes look sensible to me

Jelte Fennema-Nio <postgres@jeltef.nl> writes:
> On Sat, 3 Jan 2026 at 10:52, Peter Eisentraut <peter@eisentraut.org> wrote:
>> It has previously been established that POSIX 2008 is the baseline for
>> PostgreSQL code (modulo Windows).  Looking through the POSIX 2008
>> changes, I found a few more things we can clean up with respect to that.

> Both changes look sensible to me

+1.  I also checked the buildfarm and confirm that no animals report
not having strnlen().

I'm a little disturbed by the rindex bit, because that's not hoary old
code: it came in with JIT in v11, only about 8 years ago.  How can we
prevent similar mistakes in future?

            regards, tom lane

On 03.01.26 18:42, Tom Lane wrote:
> Jelte Fennema-Nio <postgres@jeltef.nl> writes:
>> On Sat, 3 Jan 2026 at 10:52, Peter Eisentraut <peter@eisentraut.org> wrote:
>>> It has previously been established that POSIX 2008 is the baseline for
>>> PostgreSQL code (modulo Windows).  Looking through the POSIX 2008
>>> changes, I found a few more things we can clean up with respect to that.
> 
>> Both changes look sensible to me
> 
> +1.  I also checked the buildfarm and confirm that no animals report
> not having strnlen().

committed

> I'm a little disturbed by the rindex bit, because that's not hoary old
> code: it came in with JIT in v11, only about 8 years ago.  How can we
> prevent similar mistakes in future?

AFAICT, rindex() doesn't exist on Windows, so we only got away with it 
because the JIT code is not compiled under Windows.  So in general this 
should regulate itself.