64 bit Cygwin target and _WIN64

Christopher Faylor cgf-use-the-mailinglist-please@cygwin.com
Wed Jul 18 13:44:00 GMT 2012

On Wed, Jul 18, 2012 at 02:55:41PM +0200, Corinna Vinschen wrote:
>On Jul 18 08:36, Earnie Boyd wrote:
>> On Wed, Jul 18, 2012 at 7:03 AM, Corinna Vinschen wrote:
>> > Now comes the time for _WIN64.  _WIN64 is used a *LOT* inside of the
>> > Mingw64 headers to distinguish type definitions which differ from the
>> > 32 bit version, or to declare functions which only exist on 64 bit
>> > machines, stuff like that.
>> Is it needed always or just during compilation of Cygwin? (but read on
>> before answering)
>The _WIN64 define is needed for building Cygwin as well as for building
>Cygwin applications accessing the Windows API.

Why would we worry about hypothetical nonexistent people who are trying
to build a 64-bit Cygwin app with 64-bit Windows headers?  Couldn't we
just tell them "Define _WIN64_ somewhere if you want to do this" ?  And
then we could use -D_WIN64_ on the Cygwin command line.

I think making this somewhat hard might actually help clarify that, when
building an app, Cygwin should not be conflated with Windows.


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