[Discuss-gnuradio] gr_msg_queue

[Eric Blossom]

On Thu, Jan 17, 2008 at 03:19:21PM -0500, Tim O'Shea wrote:
> Hi Eric,
> 
> I have a gnuradio question, I posted this to the list but I don't think it
> was accepted.

Sorry, you have to post from a subscribed address.  We don't generate
an automatic response since several RBL's black list us when we do...
http://gnuradio.org/trac/wiki/MailingLists

> I have a flow graph which diverges down several pathways, and ends in
> several separate gr_msg_queue's, my initial design was to have one python
> thread running as a handler for each queue,
> so each handler process would sit on delete_head() until a new item arrived.
> 
> However it seems that if any more than a single python thread is using
> delete_head() at one time, random memory access crashes seem to occur.

Do you have a simple test case that reproduces it?
If it's our bug we should fix it.

> Is there a clean way to block on multiple queues currently in svn ?

Not right now.  However you may be able to use a loop that includes

  m0 = msgq0.delete_head_nowait()
  m1 = msgq1.delete_head_nowait()

  time.sleep(0.010)

or something similar

> I saw reference to a message passing interface of some sort upcoming,
> but I assume this is not currently available ?

Not yet ready for prime time.

>    Thanks,
>    -Tim

Eric