Re: [PATCH] docs/about: Update the support statement for Windows

[Daniel P . Berrangé]

On Thu, May 05, 2022 at 04:12:11PM +0200, Thomas Huth wrote:
> On 05/05/2022 13.55, Daniel P. Berrangé wrote:
> > On Thu, May 05, 2022 at 09:14:57AM +0100, Daniel P. Berrangé wrote:
> > > On Thu, May 05, 2022 at 09:48:41AM +0200, Thomas Huth wrote:
> > > > Our support statement for Windows currently talks about "Vista / Server
> > > > 2008" - which is related to the API of Windows, and this is not easy
> > > > to understand for the non-technical users. It might also not be quite
> > > > true anymore, since we only compile-test QEMU with recent toolchains.
> > > 
> > > We documented Vista / Server 2008 because that is what our code is
> > > declaring it wants in terms of Windows public APIs:
> > > 
> > > In osdep.h we have:
> > > 
> > >    #ifdef _WIN32
> > >    /* as defined in sdkddkver.h */
> > >    #ifndef _WIN32_WINNT
> > >    #define _WIN32_WINNT 0x0600 /* Vista */
> > >    #endif
> > > 
> > > which tells Mingw / MSys not to expose windows header file declarations
> > > that post-date Vista.
> > 
> > Of course we rely on 3rd party libraries and in particular GLib2 is
> > mandatory, and it also set _WIN32_WINNT. So our constraint is the
> > newer of the _WIN32_WINNT constraint set by QEMU and whatever version
> > of GLib2 being compiled against.
> > 
> > QEMU sets a min GLib of 2.56, and that version of GLib sets 0x0601
> > which means Windows >= 7.  So even though QEMU only asks for Vista,
> > in practice our minimum is 7.
> 
> Windows 7 does not receive any security updates since 2020 anymore, so I'd
> rather would bump it to the level of Windows 8.1 directly instead. Or
> directly go for Windows 10 to mimic the behavior that we have with most of
> the Linux distros (max. two major releases at a time).

I like the simplicity of having the same rule everywhere.

I'm a little wary of people being stuck on old versions, when I see
current articles like this showing 20% of people still on Win7, way
more than Win8 surprisingly.

https://www.statista.com/statistics/993868/worldwide-windows-operating-system-market-share/


The thing with bumping the _WIN32_WINNT version higher though is that
we're not really doing it for any compelling technical reasons. Usually
when we bump min glib, it lets us cut out compatibility hacks and/or
get access to new APIs.

Bumping _WIN32_WINNT can do that, but the interesting place where that's
useful is mostly in GLib. I'm not sure what we'd make use of in the QEMU
side from setting a newer _WIN32_WINNT. Hence my suggestion that we just
let min GLib drive our min _WIN32_WINNT setting. If someone can point
to stuff we can improve in QEMU though, thanks to new _WIN32_WINNT that
could top the balance.

With regards,
Daniel
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