[IPython-dev] closing sys.stdout

John Hunter jdhunter at ace.bsd.uchicago.edu
Tue Sep 19 10:28:12 EDT 2006

Yes, it is possible to cause ipython to dump core!

johnh at jitter:~> ipython
Python 2.4.2 (#1, Feb 23 2006, 12:48:31)
Type "copyright", "credits" or "license" for more information.

IPython 0.7.2 -- An enhanced Interactive Python.
?       -> Introduction to IPython's features.
%magic  -> Information about IPython's 'magic' % functions.
help    -> Python's own help system.
object? -> Details about 'object'. ?object also works, ?? prints more.

In [1]: sys.stdout.close()
Traceback (most recent call last):
  File "<ipython console>", line 1, in ?
NameError: name 'sys' is not defined

In [2]: import sys

In [3]: sys.stdout.close()
Segmentation Fault (core dumped)

(solaris 10 x86 architecture)

This came up in a script where I had done

  fh = file(fname, 'w')
  print >>fh, 'blah'

later when debugging I did

  #fh = file(fname, 'w')
  fh = sys.stdout
  print >>fh, 'blah'

and forgot I had the close in....

I have seen modules, yes really, that explicitly call

ipython may want to hijack sys.stdout.close to prevent this kind of thing...


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