Unix Device File Emulation

[blaine]

On Apr 23, 12:27 pm, "Martin Blume" <mbl... at freesurf.ch> wrote:
> "blaine" schrieb
>
>
>
>
>
> > # Fake Nokia Screen Emulator
> > import sys, os
>
> > class nokia_fkscrn:
> >   def __init__(self, file):
> >     if not os.path.exists(file):
> >       os.mkfifo(file)
> >     self.fifodev = open(file, 'r')
> >   def read(self):
> >     while 1:
> >       r = self.fifodev.readline()
> >       print r
>
> > nokia = nokia_fkscrn('dev.file')
> > nokia.read()
>
> > This works at first, but when I write to the 'dev.file'
> > for the first time, the text is displayed as intended,
> > but then the program just keeps spitting out blank lines.
> > I can continue to write to the file
> > (using echo 'test\n' > dev.file)
> > and this shows up in my output, but amist a giant mass
> > of scrolling blank lines.  This also causes my CPU
> > usage to shoot up to 100%.
>
> > Any ideas? This is OS X 10.4
>
> while 1:
>  r = self.fifodev.readline()
>  if r: print r
>
> According to my docs, readline() returns an empty string
> at the end of the file.
> Also, you might want to sleep() between reads a little bit.
>
> IMHO. HTH.
> Martin

Oh ok, that makes sense.  Hmm.  So do I not want to use readline()? Or
is there a way to do something like 'block until the file is not
empty'?