[Python] popen3 on windows and interactive subprocesses

It depends on the application. It could be that it is writing
directly to the console, but it could also just be that it is
buffering its output since it is no longer talking directly to a
console. Interactive applications often show this quickly because
they print a prompt, but no newline, and then wait for input. The
lack of newline prevents line buffering from flushing that line.

You'll see this issue even with Python itself unless you manually
specify non-buffered with '-u' on the command line.

I don't know of a good way under Windows to defeat this unless the
application has such an option. Under Unix, you can use something
like a pty to make the application think it's actually talking to a
terminal although doing so portably across systems can be a black art
mastered by few (such as 'expect').

--
-- David
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\ David Bolen \ E-mail: db3l at fitlinxx.com /
/ 860 Canal Street, Stamford, CT 06902 \ Fax: (203) 316-5150 \
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Thanks for your help.

Just as test I tried running python -u in this environment and
got some output but it looked like garbage, I can look into that
so at least I can support running python with -u. I'm wondering
if there are any Windows APIs I could use that would get me
the data?
Under Unix I am using pty, and it works *much* better. I also looked
at some of the python expect modules and they seem to be tailored
for unix. The one that seemed to be general purpose ( at ftp.obsidian... )
didn't allow anonymous logins. :(

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I don't think so - regardless of how you execute and connect to the
process (the popen() calls under Windows eventually just call
CreateProcess anyway), it's the executed application itself that is
making the buffering choices based on the file handle representing
stdin. So unless the application itself provides some control over
this, there's very little you can do from the outside, Windows API or
not.

--
-- David
--
/-----------------------------------------------------------------------\
\ David Bolen \ E-mail: db3l at fitlinxx.com /
/ 860 Canal Street, Stamford, CT 06902 \ Fax: (203) 316-5150 \
\-----------------------------------------------------------------------/