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Re: C99 compliance for src/port/snprintf.c

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-08-15T15:56:43Z
Lists: pgsql-hackers 
On 2018-Aug-15, Robert Haas wrote:

> On Tue, Aug 14, 2018 at 7:28 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > I'm almost tempted to think that the reasons above make this a
> > back-patchable bug fix.  Comments?
> 
> No objections to changing the behavior.  Have you checked whether
> there are any noticeable performance consequences?
> 
> Back-patching seems a bit aggressive to me considering that the danger
> is hypothetical.

That was my first thought too, and my preferred path would be to make
this master-only and only consider a backpatch later if we find some
practical reason to do so.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Remove test for VA_ARGS, implied by C99.

  2. Introduce minimal C99 usage to verify compiler support.

  3. Require C99 (and thus MSCV 2013 upwards).

  4. Require a C99-compliant snprintf(), and remove related workarounds.

  5. Try to enable C99 in configure, but do not rely on it (yet).

  6. Make snprintf.c follow the C99 standard for snprintf's result value.

  7. Clean up assorted misuses of snprintf()'s result value.