[Python-Dev] Status of C compilers for Python on Windows

[Mark Lawrence]

On 26/10/2014 00:24, R. David Murray wrote:
> On Sun, 26 Oct 2014 00:19:44 +0200, Antoine Pitrou <solipsis at pitrou.net> wrote:
>> On Sun, 26 Oct 2014 09:06:36 +1100
>> Chris Angelico <rosuav at gmail.com> wrote:
>>> On Sun, Oct 26, 2014 at 8:59 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
>>>> How do you know this isn't a problem, since you haven't *tested* with
>>>> MSVC?
>>>> Why on Earth would you want to test your PEP work with an unsupported
>>>> Windows compiler and runtime, rather than with the officially supported
>>>> compiler and runtime?
>>>
>>> This discussion revolved around supporting MinGW in addition to MSVC.
>>> If it had been supported when I was doing that, I could have spun
>>> myself up a Windows build and tested it.
>>
>> My point is that your "Windows build" would not have the same behaviour
>> as a MSVC-produced Windows build, and so testing it with it would not
>> certify that your code would actually be compatible with genuine
>> MSVC builds of CPython, which we will not stop supporting.
>
> While true, I don't think that matters for Chris' point.  Given only the
> ability to build with the MSVC toolchain, his code (which might even be
> pure python for the purposes of this discussion) would not get tested on
> Windows until committed and run by the buildbots.  If he could build
> CPython using MinGW, he would, and would test his code on Windows.  Even
> if there are C components and MSVC/MinGW compatibility issues are
> revealed when the buildbots eventually run the code, still the number of
> bugs present would probably be lower if he had tested it on Windows
> than if he hadn't.
>
> I know I for one do not generally test patches on Windows because I
> haven't taken the time to learn how to build CPython on it.  Sure, I
> could test pure python changes by applying patches to an installed
> Python, but that's an ongoing pain and I'd rather learn to build CPython
> on Windows and get to use the normal hg tools.
>
> If I could use a more linux-like toolchain to build CPython on windows,
> I would doubtless do much more testing on windows for stuff where I
> think windows might behave differently (and I might look at more Windows
> bugs...though frankly there are plenty of bugs for me to look at without
> looking at Windows bugs).
>
> This is not necessarily a compelling argument for MinGW support.
> However, it *is* a valid argument, IMO.
>
> Note: it can be made even less compelling by making it a lot easier to
> build CPython on Windows without having an MSVC license (which I think
> means not using the GUI, for which I say *yay* :).  I think Zach Ware
> has been working on improving the Windows build process, and I keep
> meaning to give it a try...
>
> --David
>

MSVC Express Edition 2010 works perfectly for building 3.5 so no license 
needed.  Links to older versions have been pointed out on other threads, 
either here or python-ideas, maybe both?  Or use the command line as 
Antoine pointed out elsewhere.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence