why am I getting IOError: (9, 'Bad file descriptor') error while making print statements?

Question

I am running a python2.5 script on a windows 2003 server as a service. I am getting this error for simple print statments:

IOError: (9, 'Bad file descriptor') 

I deleted all the print statements because they were only used for development purposes, but I am unsure why a print statement would cause me any greif. I ran the same script not as a service without any major problems. Just wondering if anyone else has any insight?

Answer 1

You can't print because sys.stdout is not available when not running as a console session.

Instead of using print statements you can consider using the logging module so you can set the loglevel and write all critical things to the system event log.

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It should be noted that you can still get it to work (or silently ignore the problem) by doing something like this:

To write to a file per output stream:

import sys sys.stdout = open('stdout.txt', 'w') sys.stderr = open('stderr.txt', 'w') 

To write to a single file:

import sys sys.stdout = sys.stderr = open('output.txt', 'w') 

Or to silently ignore all print statements:

import sys class NullWriter(object):     def write(self, value): pass  sys.stdout = sys.stderr = NullWriter()