From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Allowing printf("%m") only where it actually works
Date: Mon, 21 May 2018 12:03:20 -0400
Message-ID: <31054.1526918600@sss.pgh.pa.us> (raw)
In-Reply-To: <CAEepm=2-7qBw6U-vy2OgL=Z=J6VeOzPS5jsK2PwmG0PWTDv1cg@mail.gmail.com>
References: <2975.1526862605@sss.pgh.pa.us>
<CAEepm=29o4wi5WEBFfwhBUuiYSymbTcORw_cvdaaxPPoAkrsvA@mail.gmail.com>
<14176.1526874887@sss.pgh.pa.us>
<24986.1526877413@sss.pgh.pa.us>
<CAEepm=2-7qBw6U-vy2OgL=Z=J6VeOzPS5jsK2PwmG0PWTDv1cg@mail.gmail.com>
Thomas Munro <thomas.munro@enterprisedb.com> writes:
> On Mon, May 21, 2018 at 4:36 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I am wondering whether the elog/ereport macros can locally define some
>> version of "errno" that would cause a compile failure if it's referenced
>> within the macro args. But I'm too tired to work it out in detail.
> Here's an experimental way to do that, if you don't mind depending on
> gory details of libc implementations (ie knowledge of what it expands
> too). Not sure how to avoid that since it's a macro on all modern
> systems, and we don't have a way to temporarily redefine a macro. If
> you enable it for just ereport(), it compiles cleanly after 81256cd
> (but fails on earlier commits). If you enable it for elog() too then
> it finds problems with exec.c.
Hmm ... that's pretty duff code in exec.c, isn't it. Aside from the
question of errno unsafety, it's using elog where it really ought to be
using ereport, it's not taking any thought for the reported SQLSTATE,
etc. I'm hesitant to mess with it mere hours before the beta wrap,
but we really oughta improve that.
I noticed another can of worms here, too: on Windows, doesn't use of
GetLastError() in elog/ereport have exactly the same hazard as errno?
Or is there some reason to think it can't change value during errstart()?
regards, tom lane
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, thomas.munro@enterprisedb.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Allowing printf("%m") only where it actually works
In-Reply-To: <31054.1526918600@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox