# [Python-Dev] Re: [Patches] PC\config.[hc] changes for Win64

Guido van Rossum guido@python.org
Mon, 08 May 2000 22:14:07 -0400

```> [Trent]
> > What if someone needs to do something in Python code for either Win32 or
> > Win64 but not both? Or should this never be necessary (not
> > likely). I would
> > like Mark H's opinion on this stuff.

[Mark]
> OK :-)
>
> I have always thought that it _would_ move to "win64", and the official way
> of checking for "Windows" will be sys.platform[:3]=="win".
>
> In fact, Ive noticed Guido use this idiom (both stand-alone, and as :if
> sys.platform[:3] in ["win", "mac"])
>
> It will no doubt cause a bit of pain, but IMO it is cleaner...

Hmm...  I'm not sure I agree.  I read in the comments that the _WIN32
symbol is defined even on Win64 systems -- to test for Win64, you must
test the _WIN64 symbol.  The two variants are more similar than they
are different.

While testing sys.platform isn't quite the same thing, I think that
the same reasoning goes: a win64 system is everything that a win32
system is, and then some.

So I'd vote for leaving sys.platform alone (i.e. "win32" in both
cases), and providing another way to test for win64-ness.

I wish we had had the foresight to set sys.platform to 'windows', but
since we hadn't, I think we'll have to live with the consequences.

The changes that Trent had to make in the standard library are only
the tip of the iceberg...