On Fri, May 09, 2008 at 10:35:17AM -0400, Ed Criscuolo wrote: > Are there any special considerations needed to use Linux signals > (in particular sigalarm) or forks from within a custom GnuRadio > C++ block? > > > Background information: > > I'm written a block that consumes an HDLC/MPoFR bitstream and > extracts and forwards any contained IP packets. The block > generates a number of data and error statistics which I would > like to periodically send to another system via a UDP packet, > at a rate which is unrelated to the block's sample rate. > My thought is to use alarm() to generate a sigalarm every > reporting interval, and register a private method as the > signal handler. If the reporting ends up taking too long, > I would use a fork from within the signal handler and do > the reporting in the child process. > > Is this approach workable within the GnuRadio framework? > Or are there interactions with the scheduler and/or the > use of threads that render it unworkable or unreliable? > > Thanks in advance!
Hi Ed, I'd stay away from signals and alarm. I think a "more likely to work now and in the future" approach is to have the time keeping happen in python, possibly in another thread, and have it call a method on your class when it's time to extract the results and send them via UDP. FWIW, theads and signals are a fairly nasty combination. As you've probably noticed, there's only a single signal handler for all threads, though you can mask which signals a given thread sees. With the multi-processor (MP) scheduler I'm currently working on, you'll never know what thread could to executing any given block at any given time. Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
