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io.UnsupportedOperation: fileno

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  io.UnsupportedOperation: fileno satishmlmlml@gmail.com - 2014-11-13 15:23 -0800
    Re: io.UnsupportedOperation: fileno sohcahtoa82@gmail.com - 2014-11-13 15:30 -0800
      Re: io.UnsupportedOperation: fileno satishmlmlml@gmail.com - 2014-11-13 15:34 -0800
        Re: io.UnsupportedOperation: fileno Chris Angelico <rosuav@gmail.com> - 2014-11-14 10:40 +1100
        Re: io.UnsupportedOperation: fileno Ben Finney <ben+python@benfinney.id.au> - 2014-11-14 10:42 +1100
        Re: io.UnsupportedOperation: fileno Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-11-14 05:10 +0000
      Re: io.UnsupportedOperation: fileno satishmlmlml@gmail.com - 2014-11-13 15:42 -0800
        Re: io.UnsupportedOperation: fileno Ben Finney <ben+python@benfinney.id.au> - 2014-11-14 10:52 +1100
        Re: io.UnsupportedOperation: fileno Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2014-11-14 12:29 +0100

#80717 — io.UnsupportedOperation: fileno

import sys
for stream in (sys.stdin, sys.stdout, sys.stderr):
           print(stream.fileno())


io.UnsupportedOperation: fileno

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#80718

On Thursday, November 13, 2014 3:23:24 PM UTC-8, satish...@gmail.com wrote:
> import sys
> for stream in (sys.stdin, sys.stdout, sys.stderr):
>            print(stream.fileno())
> 
> 
> io.UnsupportedOperation: fileno

Yup.  That's what I'd expect to see.

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#80719

What is the problem and how to overcome this problem?

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#80724

On Fri, Nov 14, 2014 at 10:34 AM,  <satishmlmlml@gmail.com> wrote:
> What is the problem and how to overcome this problem?

The problem is that you're posting, with no context, a query relating
to a former post which gave scanty information and no indication of
what you expected. To overcome this, read this:

http://www.catb.org/esr/faqs/smart-questions.html

ChrisA

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#80727

satishmlmlml@gmail.com writes:

> What is the problem and how to overcome this problem?

First, please provide context (just as the previous respondent did), so
your message may be understood in the absence of those prior.
<URL:https://en.wikipedia.org/wiki/Posting_style#Interleaved_style>

As to your question: Please describe what you expected, and how the
behaviour was different. Unless we know what you think is wrong, we
don't know what “the problem” is.

-- 
 \     “Sittin' on the fence, that's a dangerous course / You can even |
  `\       catch a bullet from the peace-keeping force” —Dire Straits, |
_o__)                                   _Once Upon A Time In The West_ |
Ben Finney

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#80739

On 13/11/2014 23:34, satishmlmlml@gmail.com wrote:
> What is the problem and how to overcome this problem?
>

RTFM.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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#80725

fileno() in not supported. Is it only in 3.1? What is the workaround?

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#80729

satishmlmlml@gmail.com writes:

> fileno() in not supported.

It is supported, but it is behaving as the documentation describes
<URL:https://docs.python.org/3/library/io.html#io.IOBase.fileno>.

> Is it only in 3.1? What is the workaround?

Expect an exception when you ask for the file descriptor on a stream
that does not use a file descriptor.

-- 
 \       “Pinky, are you pondering what I'm pondering?” “Well, I think |
  `\       so, Brain, but ‘apply North Pole’ to what?” —_Pinky and The |
_o__)                                                           Brain_ |
Ben Finney

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#80756

Am 14.11.2014 00:42 schrieb satishmlmlml@gmail.com:
> fileno() in not supported. Is it only in 3.1? What is the workaround?

You have been asked many times about the details of your environment.

Especially, you have been told that it is important to know if you 
directly use the Python CLI or some GUI like IDLE.

I just tested the latter thing and found out that it indeed makes a 
difference, as it introduces a replacement for the std* stuff you are 
missing:

 >>> sys.stdin
<idlelib.PyShell.PseudoInputFile object at 0x0000000002EAD588>
 >>> sys.stdout
<idlelib.PyShell.PseudoOutputFile object at 0x0000000002EAD5C0>
 >>> sys.stderr
<idlelib.PyShell.PseudoOutputFile object at 0x0000000002EAD5F8>

Calling .fileno() on such a Pseudo*File just raises an 
UnsupportedOperation exception.

This is in contrast to using the CLI directly.

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