#!/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()