Illegal seek with os.popen

[Terry Reedy]

pruebauno at latinmail.com wrote:

> Python 3.0.1 (r301:69556, Jun  4 2009, 16:07:22) [C] on aix5
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import os
>>>> os.popen('cat','w')
> <os._wrap_close object at 0x1103e5748>
> 
> So it seems to be something in 3.1 that causes it to fail.
> BTW it is not like I use os.popen a lot. I found this problem while
> trying to use help().
> 
> Python 3.1rc1 (r31rc1:73054, Jun  1 2009, 10:49:24) [C] on aix5
> Type "help", "copyright", "credits" or "license" for more information.
>>>> help(open)

On Windows xp, this works fine.

> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/Python-3.1rc1/Lib/site.py", line 429, in __call__
>     return pydoc.help(*args, **kwds)
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1709, in __call__
>     self.help(request)
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1756, in help
>     else: doc(request, 'Help on %s:')
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1505, in doc
>     pager(render_doc(thing, title, forceload))
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1320, in pager
>     pager(text)
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1340, in <lambda>
>     return lambda text: pipepager(text, 'less')
>   File "/Python-3.1rc1/Lib/pydoc.py", line 1359, in pipepager
>     pipe = os.popen(cmd, 'w')
>   File "/Python-3.1rc1/Lib/os.py", line 641, in popen
>     return _wrap_close(io.TextIOWrapper(proc.stdin), proc)
> IOError: [Errno 29] Illegal seek

Now is the time to file a bug report for this and os.popen problem;)