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Is it just me, or..

Michael P. Reilly Michael.P..Reilly at p98.f112.n480.z2.fidonet.org
Sun Jul 4 17:05:37 EDT 1999 
From: "Michael P. Reilly" <arcege at shore.net>

Markus Stenberg <mstenber at cc.Helsinki.FI> wrote:
: Is there a bug in the handling of pipes with the Python? Esp. in
: non-blocking way.

: Example:
:  (r,w)=os.pipe()
:  r = os.fdopen(r, "r", 0)
:  w = os.fdopen(w, "w", 16384)
:  w.write('foobarbaz')
:  select.select([r],[],[]) # returns r, as it should
:  r.read(1) # returns 'f'
:  select.select([r],[],[]) # blocks!

: Now select _blocks_, despite there being obviously some data that at least
: should not have been buffered elsewhere. Also, fdopened stuff's reading
: features are bit annoying, as doing read(bigNumber) results in blocking
: call, as opposed to recv(bigNumber)'s semantics. Thus instead of pipes
: (=fast) I am using TCP/UNIX sockets (=slow) but they seem to work better
: for what I need. Am I missing something really obvious?

: This is on Linux, if it matters.

At first glance, I'd say that it is the buffering in the fdopen(w, "w",
16384) call.  Put the bufsize to 0 or call the flush method.

  -Arcege
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