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
Curt Hagenlocher wrote:
Ah, that was the function I was looking for.
Sure, the file descriptor exists in the C library under Windows. But
the C library is basically doing exactly the same thing as IronPython
is; it's maintaining the file descriptor number as an abstraction on
top of the HANDLE that the operating system knows about. So we're
dealing two similar abstractions with entirely unrelated interfaces:
IronPython fd built on top of .NET stream built on top of Windows
HANDLE, vs
clib fd built directly on top of Windows HANDLE
To get from the IronPython fd to a clib fd, you need to translate down
the first chain and up the second.
On Mon, Dec 15, 2008 at 9:37 AM, Tom Wright
<tom.wri...@resolversystems.com
<mailto:tom.wri...@resolversystems.com>> wrote:
Not so: Though admittedly you have to do quite a bit of work to
get the file descriptor into .NET.
http://msdn.microsoft.com/en-us/library/bdts1c9x(VS.71).aspx
<http://msdn.microsoft.com/en-us/library/bdts1c9x%28VS.71%29.aspx>
To clarify - the C library was written to work with Python (not
IronPython) and is not my code.
Thanks,
Tom
Curt Hagenlocher wrote:
There's no such thing as a file descriptor number in .NET --
or, for that matter, in Windows itself! :) (The latter is
something of a semantic point, of course, as a HANDLE serves
something of the same role in Win32 as a file descriptor
number does in Unix.)
If you have a FileStream, I think you can turn it into a
Windows HANDLE by saying
IntPtr handle = stream.SafeFileHandle.DangerousGetHandle();
The C library should have a way to convert a HANDLE into a
"file descriptor", though I wasn't able to identify the
function name with a quick google.
I don't see a way to get handles for stdin, stdout or stderr,
though, except that these ought to be easy to translate by hand.
On Mon, Dec 15, 2008 at 8:03 AM, Tom Wright
<tom.wri...@resolversystems.com
<mailto:tom.wri...@resolversystems.com>
<mailto:tom.wri...@resolversystems.com
<mailto:tom.wri...@resolversystems.com>>> wrote:
Hi,
At the moment file.fileno() returns an arbitrary identifier
of a
python file rather than a true file descriptor. This is
semi-blocking the Ironclad port of PIL.
Code in PIL gets an integer using fileno() and passes it
directly
to C code where a call to write() is made. To fix this one
would
have to patch PIL, IronPython's file objects or the write
function
provided to C code - none of these feel like a good course
of action.
When ctypes is ported to IronPython this may create similar
problems. Ideally fileno() would return a real file descriptor.
Would this be possible?
Thanks,
Tom
Resolver Systems
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