Right way to io.open(...) an existing file object in Python 2.7?

[eryk sun]

On Tue, Jan 16, 2018 at 4:00 PM, Skip Montanaro
<skip.montanaro at gmail.com> wrote:
> I'd like to take advantage of the seekable() method of io.IOBase with
> existing open file objects, especially the standard in/out/err file
> objects.

io.open can open a file descriptor. If you don't use a duplicated FD
(os.dup), then you probably also want the option `closefd=False`. For
example:

$ cat test.py
    import sys
    import io

    stdin = io.open(sys.stdin.fileno(), closefd=False)
    print 'stdin seekable: %s' % stdin.seekable()

$ python test.py
    stdin seekable: False

$ echo spam | python test.py
    stdin seekable: False

$ python test.py < test.py
    stdin seekable: True