[Discuss-gnuradio] Re: gr_top_block adding new block while running

[Engin Karabulut]

Engin Karabulut wrote:

> hi all,
> 
> I want to record for example a fir filter output
> to file when I want. I have develop basic application,
> given some parts below
> 
> .....
> .....
> def start_record_samples (self):
>         self.stop()
>         self.utfil = gr.file_sink(gr.sizeof_float,"capture.cfile")
>         self.connect(self.chan_filt,self.utfil)
>         self.start()
>               
> def stop_record_samples (self):
>         self.stop()
>         self.disconnect(self.chan_filt,self.utfil)
>         self.start()
> 
> .....
> .....
> 
> these functions are controlled with two buttons. "start" button calls
> start_record_samples and "stop" button calls stop_record_samples.
> 
> but they don't work properly.
> 
> start_record_samples gives error given below,
> 
> Traceback (most recent call last):
>   File "/usr/local/lib/python2.5/site-packages/gnuradio/wxgui/form.py",
>   line
> 33, in <lambda>
>     wx.EVT_BUTTON(parent, new_id, lambda evt: callback())
>   File "usrp_snby_rcv.py", line 219, in record_samples
>     self.start_record_samples()
>   File "usrp_snby_rcv.py", line 227, in start_record_samples
>     self.start()
>   File "/usr/local/lib/python2.5/site-packages/gnuradio/gr/top_block.py",
> line 72, in start
>     self._tb.start()
>   File "/usr/local/lib/python2.5/site-
> packages/gnuradio/gr/gnuradio_swig_py_runtime.py", line 1411, in start
>     return _gnuradio_swig_py_runtime.gr_top_block_sptr_start(*args,
> **kwargs)
> RuntimeError: top_block::start: top block already running or wait() not
> called after previous stop()
> 
> how can  I add new block temporarily to a running gr_top_block scheduler?
> because after stop it can't start anymore.
> 
> regards.

I have found the solution from gr wiki. I just add self.wait() before 
self.start and everything is fine now.