Redirecting stdout/err under win32 platform

[David Douard]

Alan,

I did search Google for this problem (not enough, thou).
In fact, I found some kind of solution (by myself, not that much on Google),
but it is not really satisfactory.

I have used win32 pipes to do so (win32api.CreatePipe). I can redirect
stdout/stderr to it from my python code (even redirecting the stdout/stderr
from my C lib). 
But I still have a problem with this solution (well, 2):
- it is *much* more complicated than any solution available on Unix like
systems (not really a problem, but),
- it not synchronous at all. And I'd like it to be so (or almost so).

David



yaipa wrote:

> David,
> 
> Googling comp.lang.python /w this string "stderr win32" yielded 109
> results.
> So I think if you poke around a bit you will find your answer in the
> archives.
> 
> Sorry for no direct help tonight...
> 
> Cheers,
> 
> --Alan
> David Douard wrote:
>> Hi everybody,
>>
>> let me explain by problem:
>> I am working on an application which consists in a C++ dll (numeric
>> computations) and a Python IHM (Python/Tk), which must run under
> Linux and
>> win32. My problem is the C++ lib does write stuffs on its stdout, and
> I
>> would like to print those messages in a Tk frame. When I run the
>> computation, it has it's own thread.
>>
>> So my question is : how van I redirect the dll's stdout to something
> I can
>> retrieve in Python (pipe, socket,...)?
>>
>> I can do it easily under Linux. I made tests with a socket which just
> works
>> fine. In the threaded function (that will do the heavy computation),
> I
>> write:
>>
>> import os, sys
>> from socket import *
>> s=socket(AF_UNIX, SOCK_STREAM)
>> s.connect(...)
>> os.dup2(sys.__stdout__.fileno(), s.fileno())
>> very_intensive_function(many_parameters)
>> s.close()
>>
>> That's OK under Linux, but does not work under win32 (even if I use
> an INET
>> localhost socket), cause I cannot do the os.dup2 trick (Windows does
> not
>> want to consider a socket as a file! What a shity system!).
>>
>> So my question is : is there a simple solution ? I have tested
> different
>> solutions. I am trying hacks with pipes created with the win32api.
> But I
>> have not yet managed this simple operation.
>>
>> Note that I have no access to the dll source code, so I cannot modify
> it so
>> it uses a named pipe (for example) as message output pipe instead os
>> stdout...
>> 
>> Thanks,
>> David