I have a simple gnuradio flowgraph inside a Python script that takes data from a usrp source and does some simple processing
with the fft block. The results are written in a file sink. I start the graph using the start() method, let it run for 100 ms,
then stop it using the stop() and wait() methods. In the Python script that contains the flowgraph, there is a piece of code
that reads data from the file sink and does some processing. I then change the usrp tune frequency and couple of other parameters
and repeat the process.
The problem is that the file keeps growing and I want to discard all previous data once I set the new parameters. It doesn't
matter if I set 'append' to false. The file keeps growing as long as the flowgraph exists. I can terminate the flowgraph every
time I want to change the parameters but that's not a convenient option because everything has to be reinitialized inside the usrp
including the fpga bitfile.
Is there a better way to transfer data between the flowgraph and the top level Python script? I was going to use something
like a simple buffer that could be cleared but I couldn't find anything like that in the gnuradio library.
Ivan