[Discuss-gnuradio] Getting the Count of FFTs

Hi all,

I have a GNU Radio flowgraph which uses a USRP to receive a signal, converts it to log power FFT and then writes the result to a file, using File Sink. I want to have a counter which increments with each FFT written to the file.

Is there a way of maintaining and increasing count of the FFTs written to the file, while the flowgraph is still running?