I'm converting some os.popen calls to use subprocess.Popen. I had previously been ignoring stdout and stderr when using os.popen. The primary motivation to switch to subprocess.Popen now is that I now want to check stderr, so would have to make code changes to use os.popen[34] anyway. Might as well go whole hog and switch to the new API.
The library documentation doesn't talk a lot about long-lived subprocesses other than the possibility of deadlock when using Popen.wait(). Ideally, I would write to the subprocess's stdin, check for output on stdout and stderr, then lather, rinse, repeat. Is it safe to assume that if the stdout and/or stderr pipes have nothing for me the reads on those file objects (I'm using PIPE for all three std* files) will return immediately with an empty string for output? They won't block, will they? Will a broken pipe IOError get raised as for os.popen() or do I have to call Popen.poll() even in error situations? Thanks, -- Skip Montanaro - s...@pobox.com - http://www.smontanaro.net/ -- http://mail.python.org/mailman/listinfo/python-list
