Re: [Discuss-gnuradio] UDP source block in GRC

[Eric Blossom]

On Fri, Apr 23, 2010 at 09:44:51AM -0400, Don Ward wrote:
> 
> ----- Original Message ----- From: "Eric Blossom" <address@hidden>
> To: "Marcus D. Leech" <address@hidden>
> Cc: "GNURadio Discussion List" <address@hidden>
> Sent: Thursday, April 22, 2010 6:24 PM
> Subject: Re: [Discuss-gnuradio] UDP source block in GRC
> 
> 
> >On Fri, Apr 09, 2010 at 10:23:43PM -0400, Marcus D. Leech wrote:
> >>I'm trying to use a UDP source block from a GRC-produced flowgraph.
> >>
> >>The only thing it does is this:
> >>
> >>gr_block_executor: source <gr_block udp_source (2)> produced no output.
> >>We're marking it DONE.
> >
> >The udp source/sink needs an overhaul.
> >
> >This error is triggered to indicate that the block (a source) is
> >returning zero, and thus is most likely spinning.
> 
> Whatever overhauling is done, it would nice to have the option of
> treating zero-bytes-read from gr_udp_souce as an EOF condition.  A
> client can then decide whether to wait for a server or give up.  (It
> might also be nice to have program access to the timeout value.)
> 
> -- Don W.

Hi Don,

Probably the "right answer" is to add support in the system for
sending messages to blocks when file descriptors "select" true for
read, write or exception conditions.  This would remove the problem
with blocking on something that might never happen, or the current
dodgy work-around of blocking with a timeout.

Eric