[Discuss-gnuradio] How to stop top block?

[Yan Wang]

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.