Horton

Re: PRI?64 vs Visual Studio (2022)

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2025-11-19T02:13:54Z
Lists: pgsql-hackers

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

  1. Test PRI* macros even when we can't test NLS translation.

  2. Avoid requiring Spanish locale to test NLS infrastructure.

  3. Drop support for MSVCRT's float formatting quirk.

  4. Drop support for MSVCRT's %I64 format strings.

  5. Use PRI?64 instead of "ll?" in format strings (continued).

  6. Use <stdint.h> and <inttypes.h> for c.h integers.

  7. Make float exponent output on Windows look the same as elsewhere.

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On Wed, Apr 2, 2025 at 2:04 AM Peter Eisentraut <peter@eisentraut.org> wrote:
> On 31.03.25 08:28, Kyotaro Horiguchi wrote:
> > I hadn’t paid much attention to this before, but I happened to check
> > how this behaves on Windows, and it seems that with VS2022, PRId64
> > expands to "%lld". As a result, I suspect the gettext message catalog
> > won't match these messages correctly.
>
> I think this is working correctly.  Gettext has a built-in mechanism to
> translate the %<PRI...> back to the appropriate  %lld or %ld.  See also
> <https://www.gnu.org/software/gettext/manual/html_node/c_002dformat.html>.

Interesting report though.  Commit 962da900 assumed that our in-tree
printf implementation still needed to understand that %I64 stuff in
case it came to us from system headers, but it looks like it
disappeared with MSVCRT:

1. I checked with CI (VS 2019).  puts(PRId64) prints out "lld".
2. MinGW's inttypes.h[1] only uses "I64" et al if you build against MSVCRT.

So I think we should delete that stuff.  Attached.

I worried that GNU gettext() might still know about %I64 somewhere,
but it just expands the macros to whatever inttypes.h defines[2].
Good.

We don't even test -Dnls on the Windows CI task, so the fact that it
passes there doesn't mean much (if our tests would even pick up
<PRI*64> expansion failure, not sure).  We should probably do
something about that and/or its absence from the build farm.  We're
effectively counting on the EDB packaging team or end users to tell us
if we break localisation on this platform.

I was also curious to know if the nearby floating point formatting
kludge added by commit f1885386 was still needed today.  CI passes
without it, and the standard is pretty clear: "The exponent always
contains at least two digits, and only as many more digits as
necessary to represent the exponent".  I didn't look too closely at
the fine print, but that text was already present in C89 so I guess
MSVCRT just failed to conform on that point.

[1] https://github.com/mingw-w64/mingw-w64/blob/master/mingw-w64-headers/crt/inttypes.h
[2] https://github.com/autotools-mirror/gettext/blob/637b208fbe13f1c306f19d4f31c21fec7e9986d2/gettext-runtime/intl/loadmsgcat.c#L473