embedding: how do I redirect print output?
t at jollybox.de
Tue Jul 5 16:18:20 CEST 2011
On 07/05/2011 02:50 PM, Ulrich Eckhardt wrote:
> I'm trying to add some scripting capabilities to an application. Since it is
> a GUI application, I need some way to display output from Python. For 3.x,
> where "print" is a function, I'd just exchange this function with one that
> redirects the output to a log window, right.
> However, I'm using 2.6 here, where that can't work. So, what I was thinking
> was to redirect "sys.stdout" and "sys.stderr" to a log window and possibly
> replace "sys.stdin" with something that causes meaningful errors if some
> code tries to use it, but that last point is just icing on the cake.
> What seems cumbersome is that I'll need to write something that supports the
> file interface using C, which is still a bit awkward. I'm wondering, isn't
> there an easier way to achieve this? How would you do it?
You can mess with low-level file descriptors. Example:
# create new stdout:
fout = file('out.txt', 'w')
# close stdout (fd 1)
# use fout as new stdout
# test. This will end up in out.txt
# do the same for stdin (0) and stderr (2)
# - EOF -
However, I suggest you consider isolating your scripts from you main
program and run them in a separate interpreter. You can provide dummy
modules that communicate with your application via sockets to the
scripts. Setting the standard files in the child process is easy: the
Popen constructor takes stdin/stdout/stderr arguments.
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