64 bit Cygwin target and _WIN64

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Jul 19 11:00:00 GMT 2012

On Jul 19 11:40, Pedro Alves wrote:
> On 07/19/2012 09:40 AM, Corinna Vinschen wrote:
> > I had a more or less sleepless night thinking about this stuff, but the
> > more I think about it, the more I think that just #defining _WIN64 in
> > the Windows headers if called from a x86_64-targeting Cygwin compiler is
> > the right thing to do.  On one hand a 64 bit Cygwin application will
> > get the correct Windows definitions, on the other hand the impact on the
> > Mingw64 headers is minimal.
> You might even get zero impact on the Mingw64 headers, if you find a central
> Windows header that all other headers include first (ISTR there used to be one,
> windef.h, mingw.h or something like that on the w32api side), and put a Cygwin-specific
> one with the same name earlier on the Cygwin system include search paths
> that just does:
> #define _WIN64
> #include_next <foo_central_header_whatever_its_called_maybe_windef.h>
> This header would be controlled and shipped by Cygwin.

Right, but since we already have our own header in Mingw64 which is
included practically always, that's not much of a problem.  I can
pretty much define what I want in that file.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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