Re: [Discuss-gnuradio] How to stop top block?

[Eric Blossom]

On Fri, Aug 21, 2009 at 12:03:51AM +0000, Yan Wang wrote:
> Hello,
> I am trying to change some options dynamically. Right now I am trying this 
> with benchmark_ofdm_rx.py, I add one new class for dynamically enter the new 
> option value and change it in the program. However I found those options, 
> except center frequency and gain, all cannot be effectively changed just 
> by "disconnec+rebuild a receive_path+connect". I did successfully change the 
> options and make it work through that way, but that's only before I start the 
> my_top_block, once the top block started, nothing can be effectively changed
> (again except center frequency).
> 
> On way I thought about is to stop the top block before changeing the value, 
> but that's also no way to do that, because the top block won't stop indeed 
> even I use tb.stop().(This can be proved that the top block cannot be 
> restarted by tb.start(), errors will come up saying top block is running).
> 
> Is there any effective way to change options dynamically or stop/start the 
> top 
> block?
> 
> Thanks a lot.

No need to stop the graph to alter the connections.

Use lock/unlock.  E.g.,

  top_block.lock()
  disconnect(...)
  ...
  connect(...)
  ...
  top_block.unlock()


There are some exxamples that do this, and there's been discussion on
the mailing list.

Eric