Running multiple flow graphs simultaneously

Hi -

Is it possible to run more than one top_block at a time in gnuradio
3.7.x? I have an application where I wish to run an additional flow
graph periodically. I have set up a thread that grabs samples via a
probe from my main flow graph that is running all of the time, and uses
that data to source another flow graph. Everything appears to be
running, however I want to be certain that I’m not doing something
terribly wrong — especially since two relevant sources of information
seem to contradict my current mode of operation:

From the Python application writing tutorial (June 2008)
http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsWritePythonApplications

From a January 2012 gnuradio mailing list post:
http://lists.gnu.org/archive/html/discuss-gnuradio/2012-01/msg00145.html

Best,
Rob

On 04/01/2014 11:29 PM, Rob M. wrote:

Is it possible to run more than one top_block at a time in gnuradio
3.7.x? I have an application where I wish to run an additional flow
graph periodically. I have set up a thread that grabs samples via a
probe from my main flow graph that is running all of the time, and uses
that data to source another flow graph. Everything appears to be

Yes, you can do that.
It might not be what you want – running 2 top_blocks is a bit like
running 2 processes with one tb each.
You can have a disconnected flow graph in one top block by making each
FG a hier block, and then adding that to the top block.

From a January 2012 gnuradio mailing list post:

Re: [Discuss-gnuradio] Multiple flow graphs, proper design

It used to be that you could only have 1 top_block per process. The wiki
page is not up to date.

M