Weirdness with python and stdin redirection under Win32

[Piet van Oostrum]

>>>>> bokr at oz.net (Bengt Richter) (BR) writes:

BR> On 04 Dec 2002 13:53:59 +0100, Piet van Oostrum <piet at cs.uu.nl> wrote:
>>>>>>> bokr at oz.net (Bengt Richter) (BR) writes:
>> 
BR> On Tue, 3 Dec 2002 20:56:31 -0600, "Jonathan M. Gilligan" <jonathan.gilligan at vanderbilt.edu> wrote:
>>>> I am getting an error reading stdin only when I invoke a python script by
>>>> typing "bar | foo.py" or "foo.py < bar", but not when typing "bar | python
>>>> foo.py" or "python foo.py < bar". The error arises ecause when input is
>>>> redirected, stdin has fileno = -1 if the script is invoked as "foo.py", but
>>>> correctly has fileno = 0 if it is invoked as "python foo.py"
>>>> 
BR> [...]
>> 
BR> You have bumped into a well-known bug present in many but not all versions
BR> of windows.
>> 
BR> A number of versions of windows do not correctly set up for redirected i/o
BR> when a script is run based on running an interpreter selected by automatic
BR> association via the script's file extension. This will affect e.g., perl also.
>> 
BR> The workaround is to invoke the interpreter explicitly, as in python foo.py
BR> (as you did) or to put that in a .cmd or .bat file and then use that file
BR> as the executable, and redirect i/o wrt to that.
>> 
>> There are also Windows versions where batch files have that same bug!!
BR> Ick. I didn't know that ;-/
BR> Can you mention a specific example?

E.g. on Windows 98, make a file test1.bat, containing just:
DIR

and then run from a command prompt:
test1 > out

The output just goes to your screen, and the file out will be empty.
-- 
Piet van Oostrum <piet at cs.uu.nl>
URL: http://www.cs.uu.nl/~piet [PGP]
Private email: P.van.Oostrum at hccnet.nl