Re: [Discuss-gnuradio] Freeze when writing to linux fifo pipe

[Eric Blossom]

On Wed, Apr 21, 2010 at 11:30:32PM -0400, Marcus D. Leech wrote:
> On 04/21/2010 11:26 PM, Eric Blossom wrote:
> > On Tue, Apr 20, 2010 at 02:57:04PM +0200, Joachim Roop wrote:
> >   
> >> Hi,
> >> I am trying to write to a linux pipe/fifo, but sadly this seems to freeze 
> >> python. I am using Ubuntu 10.04 and gnuradio 3.2.2.dfsg-1ubuntu1.
> >> Please try to execute the code and tell me why this makes the app pause.
> >>     
> >  $ man 3 mkfifo
> >
> > Opening a fifo for reading blocks until there is a writer and vice versa...
> >
> > Eric
> >
> >
> >   
> Actually, an open for read will *always* succeed, lest you create
> unpleasant deadlock situations...

Hmmm.  FWIW, from Linux: man 3 mkfifo

Opening a FIFO for reading normally blocks until some other process
opens the same FIFO for writing, and vice versa.  See fifo(7) for
non-blocking handling of FIFO special files.

Eric