On 11/03/2014 09:03 PM, Gilles Chanteperdrix wrote: > On Mon, Nov 03, 2014 at 09:01:32PM +0100, Philippe Gerum wrote: >> On 11/03/2014 07:37 PM, Steve M. Robbins wrote: >>> On Mon, Nov 03, 2014 at 05:29:53PM +0100, Philippe Gerum wrote: >>> >>>> Just to make sure we are on the same page, as Dietmar mentioned in an >>>> earlier mail, read() as implemented by the rt-pipe driver only returns >>>> _one_ message at a time, although > 1 could be pending. One has to >>>> iterate over a read() loop using a non-blocking fd on the /dev/rtp >>>> device to get them all. >>> >>> Aha! Thanks (and to Dietmar). I completely missed this fact. I'll >>> go re-write the read as a loop and see if it works better. I should read >>> until the read() returns 0 (bytes read)? >>> >> >> Until you get -1 with errno == EWOULDBLOCK. Zero would rather mean that >> the other end of pipe has been disconnected, just like with a regular FIFO. >> > > Just a stupid question: should not calling select then read make as > long as there are some messages to read? >
That would be the normal option, but Steve observes issues with this pattern, we are trying to find out whether a loss of event notification might be at work in the poll() handler basically. I still can't see it reading the code though, but we cannot rule out any option at this stage. -- Philippe. _______________________________________________ Xenomai mailing list [email protected] http://www.xenomai.org/mailman/listinfo/xenomai
