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Date: Sat, 18 Oct 2014 12:32:07 -0500
From: Tim Chase <python.list@tim.thechases.com>
To: Nobody <nobody@nowhere.invalid>
Subject: Re: Flush stdin
In-Reply-To: <pan.2014.10.18.16.55.19.164000@nowhere.invalid>
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On 2014-10-18 17:55, Nobody wrote:
> On Fri, 17 Oct 2014 12:38:54 +0100, Empty Account wrote:
>=20
> > I am using netcat to listen to a port and python to read stdin
> > and print to the console.
> >=20
> > nc -l 2003 | python print_metrics.py
> >=20
> > sys.stdin.flush() doesn=E2=80=99t seem to flush stdin,
>=20
> You can't "flush" an input stream.

You can't flush it, but you can make it unbuffered.  You can either
force python to use unbuffered stdio:

  python -u myfile.py

or you can get an unbuffered handle to the file

 import os, sys
 buffer_size =3D 1
 new_stdin =3D os.fdopen(sys.stdin.fileno(), 'r', buffer_size)
 for c in new_stdin:
   do_something(c)

though based on my reading, the first method works with both Py2
and Py3k while the second method doesn't reliably work in Py3k.

-tkc