[IronPython] IronPython and file descriptors

Dino Viehland dinov at microsoft.com
Mon Dec 15 19:49:46 CET 2008

Presumably CPython is linking against msvcrt and is using the C abstraction rather than calling the Win32 APIs which return handles directly.

As Curt said the biggest problem for us is that .NET does not expose C file descriptors.  Therefore we could fix this by P/Invoking out to msvcrt.  For users on other platforms we'd need to either add support for their platform or hope that their handles == C runtime file descriptors.  For something like fileno maybe this is ok because it's an interop point only - or are there any non-interop uses of fileno in the world?

What do people think of this?  This would be the 1st place where we would add a P/Invoke so I'd want to tread lightly and make sure this is really the right thing to do.

-----Original Message-----
From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Slide
Sent: Monday, December 15, 2008 10:21 AM
To: Discussion of IronPython
Subject: Re: [IronPython] IronPython and file descriptors

On Mon, Dec 15, 2008 at 11:18 AM, Tom Wright
<tom.wright at resolversystems.com> wrote:
> Agreed. It is certainly possible with some work to get a file descriptor and
> pass it to C code.
> This is not the problem, however. Ironclad's aim (eventually) is to allow
> *arbitrary* C extensions  to work with Ironpython without changing the
> extensions. Ctypes aim is to allow arbitrary C code to be run by python
> (possibly in other python libraries which you really don't want to modify).
> In CPython .fileno() is a file descriptor and some modules use this fact
> (specifically PIL) by passing file descriptors as integers into C code. I do
> not know how one can make this code work in IronPython unless .fileno()
> returns a file descriptor.
> The game here is not making a particular C library work with IronPython by
> modifying this library but making as many libraries as possible work without
> modification. Of course whether this is worthwhile depends on how many
> libraries rely on this fact.
> Sorry - I hope this is a little clearer.
> Tom

How does CPython get the file descriptor for fileno()? Does it just
return the HANDLE on Windows?

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