Re: gettimeofday.c windows version?

From: Roger Pack <rogerdpack@gmail.com>
To: Bruno Haible <bruno@clisp.org>
Cc: bug-gnulib@gnu.org, Eli Zaretskii <eliz@gnu.org>
Subject: Re: gettimeofday.c windows version?
Date: Fri, 23 Dec 2022 01:38:01 -0700	[thread overview]
Message-ID: <CAPfeOnvpX3i0CCgzSEksSrDvcTG5zLHfW55AAWZU4xvtbZoXTw@mail.gmail.com> (raw)
In-Reply-To: <2153083.vXnMlVU4IS@nimes>

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On Sun, Dec 11, 2022 at 7:22 AM Bruno Haible <bruno@clisp.org> wrote:

> Roger Pack wrote:
> > I received some complaints saying in mingw it was"requiring windows 8"
> for
> > a certain library.
> >
> > "Entry point not found, GetSystemTimePreciseAsFileTime could not be
> located
> > in the dynamic link library KERNEL32.dll".
>
> Indeed, according to <
> https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime
> >
> the function GetSystemTimePreciseAsFileTime is not present in Windows 7 and
> older.
>
> Looking at the table at
> <https://en.wikipedia.org/wiki/Microsoft_Windows#Timeline_of_releases> I
> see
> that Windows 7 is out of "extended support" already for more than 2 years.
> That means, users with such machines (connected to the internet) live very
> dangerously.
>
> Eli: What are the current support statements of Emacs regarding Windows
> XP/Vista/7 ?
> And should Gnulib declare that the minimum supported version of Windows
> is Windows 8?
>
> > Perhaps the following patch?  Thanks! :)
> >
> > diff --git a/lib/gettimeofday.c b/lib/gettimeofday.c
> > index 36c7920af..428cc4f30 100644
> > --- a/lib/gettimeofday.c
> > +++ b/lib/gettimeofday.c
> > @@ -35,7 +35,7 @@
> >  # undef LoadLibrary
> >  # define LoadLibrary LoadLibraryA
> >
> > -# if !(_WIN32_WINNT >= _WIN32_WINNT_WIN8)
> > +# if (_WIN32_WINNT >= _WIN32_WINNT_WIN8)
> >
> >  /* Avoid warnings from gcc -Wcast-function-type.  */
> >  #  define GetProcAddress \
> >
>
> Nope, this patch is not right.
>
> > "Entry point not found, GetSystemTimePreciseAsFileTime could not be
> located
> > in the dynamic link library KERNEL32.dll".
>
> It looks like some code links directly to GetSystemTimePreciseAsFileTime,
> and
> your user is running it under Windows 7 or older.
>
> Which object file is it that links to GetSystemTimePreciseAsFileTime?
>  - If it's not gettimeofday.c, it's not in Gnulib's responsibility.
>  - If it is gettimeofday.c, this file must have been compiled with a
>    _WIN32_WINNT value >= _WIN32_WINNT_WIN8. You need to look in your
>    build files where this value come from. Maybe it is even the default
>    with your compiler version; if that version is new enough, that would
>    make sense.
>

OK it appears newer mingw have a default target of windows 10 for some
reason.  gnutls embedded in this case:
$ x86_64-w64-mingw32-gcc -DHAVE_CONFIG_H -I. -I../..   -U_FORTIFY_SOURCE
-D_FORTIFY_SOURCE=0  -mtune=generic -O3 -MT gettimeofday.o -MD -MP -MF
$depbase.Tpo -c -o - -dM -E gettimeofday.c | grep WIN32_WINNT
#define _WIN32_WINNT 0xa00
https://www.mail-archive.com/mingw-w64-public@lists.sourceforge.net/msg18212.html

Maybe instead it could always call initialize and "prefer"
GetSystemTimePreciseAsFileTime, then be compatible with < windows 8 without
having to manually set _WIN32_WINNT.
Basically everything using Gnulib gettimeofday + mingw today might
"accidentally" lose windows 7 compat without realizing it.  Though I guess
you could call that Mingw's fault, it was a bit confusing.
Thanks, Merry Christmas!

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