Subject: Re: Unneeded volatile qualifier in fmgr.c

From: Bertrand Drouvot <[email-masked]>
Date: Wed, 12 Feb 2025 08:41:34 +0000

Hi,

On Wed, Feb 12, 2025 at 04:25:38PM +0800, Julien Rouhaud wrote:
> Hi,
> 
> While reading some code in fmgr.c I noticed that the save_nestlevel variable is
> declared as volatile.  I'm assuming that's because a long time ago it was
> modified in the PG_TRY / PG_CATCH block but it doesn't look needed anymore.
> 
> Trivial patch attached.

Yeah, makes sense to me.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

---

From: Nathan Bossart <[email-masked]>
Date: Wed, 12 Feb 2025 09:38:04 -0600

>> modified in the PG_TRY / PG_CATCH block but it doesn't look needed anymore.

It was modified in the PG_CATCH section when it was first added in commit
2abae34, but that part was removed a week later in commit 82a4798.  But I'm
not even sure it needed the volatile marker in the first commit, based on
the comment in elog.h:

 * Note: if a local variable of the function containing PG_TRY is modified
 * in the PG_TRY section and used in the PG_CATCH section, that variable
 * must be declared "volatile" for POSIX compliance.

AFAICT it was never modified in the PG_TRY section.

In any case, I don't see a problem with removing "volatile" now, so I'll
plan on committing this later today if there are no objections.

-- 
nathan