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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: David Steele <david@pgmasters.net>, pgsql-hackers@lists.postgresql.org
Date: 2018-08-15T22:31:10Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2018-08-15 18:13:59 -0400, Tom Lane wrote:
>> Experimenting here says that even reasonably modern gcc's won't take
>> declarations-inside-for without "--std=c99" or such.

> I think autoconf's magic knows about most of that:
>  — Macro: AC_PROG_CC_C99

Ah, of course.  What about the MSVC build?

> I think we could get a start by adding that test to configure, without
> relying on it for now (i.e. keeping mylodon with -Wc99-extensions
> -Werror=c99-extensions alive). That'd tell us about which machines,
> besides presumably gaur, we'd need to either kick to the curb or change.

Sure, no objection to putting that in just to see how much of the
buildfarm can handle it.  If the answer turns out to be "a lot",
we might have to reconsider, but gathering data seems like the
first thing to do.

			regards, tom lane

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.