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

[Daniel P . Berrangé]

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.

Given that we should increase QEMU's own _WIN32_WINNT value to 0x601
too, since its impossible to build with older GLib than 2.56.

Next time we bump GLib min version, we should remember to check
their _WIN32_WINNT value.

With regards,
Daniel
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