#!/usr/bin/env python

from gnuradio import gr

from gnuradio import uhd

from time import sleep, time

from grc_gnuradio import blks2 as grc_blks2

class top_block(gr.top_block):

        def __init__(self):

                gr.top_block.__init__(self, "Top Block")

                self.sink_queue = gr.msg_queue(10240)

                self.msg_sink = gr.message_sink(gr.sizeof_float, self.sink_queue, False)

                self.sig = gr.sig_source_f(8000000, gr.GR_SIN_WAVE, 350, .5, 0)

                self.null_sink = gr.null_sink(gr.sizeof_float)

                self.connect(self.sig, self.msg_sink)

                self.connect(self.sig, self.null_sink)

if __name__ == '__main__':

        tb = top_block()

        tb.start()

        sleep(1)

        while(1):

                while(tb.sink_queue.count()>0):

                        tb.sink_queue.flush()

                        tb.lock()

                        tb.unlock()

                        sleep(0.001)

                print 'noflow'

                sleep(0.5)

        tb.stop()