[Python-Dev] Why spawnvp not implemented on Windows?

Tim Peters tim.peters at gmail.com
Fri Oct 13 03:04:04 CEST 2006

[Alexey Borzenkov]
>>> Umm... do you mean that spawn*p* on python 2.5 is an absolute no?

[Martin v. Löwis]
>> Yes. No new features can be added to Python 2.5.x; Python 2.5 has
>> already been released.

[Alexey Borzenkov]
> Ugh... that's just not fair. Because of this there will be no spawn*p*
> in python for another two years. x_x

Or the last 15 years.  Yet somehow people still have kids ;-)

> ...
> But the fact that I have to use similar code anywhere I need to use
> spawnlp is not fair.

"Fair" is a very strange word here.  Pain in the ass, sure, but not
fair?  Doesn't make sense.

> ...
> P.S. Although it's a bit stretching, one might also say that
> implementing spawn*p* on windows is not actually a new feature, and
> rather is a bugfix for misfeature.

No.  Introducing any new function is obviously a new feature, which
would become acutely and catastrophically visible as soon as someone
released code using the new function in 2.5.1, and someone tried to
/use/ that new code under 2.5.0.  Micro releases of Python do not
introduce new features -- take that as given.  It's been tried before,
for what appeared to be "very good reasons" at the time, and we lived
to regret it deeply.  It won't happen again.

> Why every other platform can benefit from spawn*p* and only Windows can't?

Just the obvious reason:  because so far nobody cared enough to do the
work of writing code, docs and tests for some of these functions on

> This just makes os.spawn*p* useless: it becomes unreliable and can't be
> used in portable code at all.

It's certainly true that it can't be used in portable code, at least
not before Python 2.6.

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