On Thu, Apr 24, 2014 at 12:01 AM, Damon <[email protected]> wrote:
> Hi Tom,
>
> Thanks for you reply.
>
> I am wondering why the data stream ports of byte or integer 8 could be
> disconnected by other ports.
>
> Here is an example. The connecting code is commented out, but we can run
> this program without getting a error.
>
> #!/usr/bin/env python
> ##################################################
> # Gnuradio Python Flow Graph
> # Title: Top Block
> # Generated: Thu Apr 24 11:57:08 2014
> ##################################################
>
> from gnuradio import blocks
> from gnuradio import eng_notation
> from gnuradio import gr
> from gnuradio.eng_option import eng_option
> from gnuradio.filter import firdes
> from optparse import OptionParser
>
> class top_block(gr.top_block):
>
> def __init__(self):
> gr.top_block.__init__(self, "Top Block")
>
> ##################################################
> # Variables
> ##################################################
> self.samp_rate = samp_rate = 32000
>
> ##################################################
> # Blocks
> ##################################################
> self.blocks_null_source_0 = blocks.null_source(gr.sizeof_char*1)
> self.blocks_null_sink_0 = blocks.null_sink(gr.sizeof_char*1)
>
> ##################################################
> # Connections
> ##################################################
> #self.connect((self.blocks_null_source_0, 0),
> (self.blocks_null_sink_0, 0))
>
>
> # QT sink close method reimplementation
>
> def get_samp_rate(self):
> return self.samp_rate
>
> def set_samp_rate(self, samp_rate):
> self.samp_rate = samp_rate
>
> if __name__ == '__main__':
> parser = OptionParser(option_class=eng_option, usage="%prog:
> [options]")
> (options, args) = parser.parse_args()
> tb = top_block()
> tb.start()
> raw_input('Press Enter to quit: ')
> tb.stop()
> tb.wait()
>
>
>
> Best regards,
> Damon
>
I really don't understand the question. Why do you think this behavior is
wrong? There are no blocks in the flowgraph; that's not a condition to say
it won't run. When you hit start, it'll try to start all threads; there are
none, so it will immediately exit. The raw_input is a Python thing, so that
will continue to block.
Tom
> 2014-04-23 21:46 GMT+08:00 Tom Rondeau <[email protected]>:
>
> On Tue, Apr 22, 2014 at 5:09 AM, Damon <[email protected]> wrote:
>>
>>> Hi all,
>>>
>>> Recently I am learning the grextras project. I am confused about the
>>> message port which is designed in grextras.
>>> Why will we not get a error when the message ports do not connect to
>>> other message ports? I thought those port actually is data stream ports,
>>> so they should be connected to other ports.
>>>
>>> Best regards,
>>> Damon
>>>
>>
>> Damon,
>> grextras is an external project from GNU Radio and not related to the
>> core functionality.
>>
>> But GNU Radio's message passing structure does not require connections.
>> It's a publish-subscribe model, and a block will publish a message
>> regardless of whether or not another block is subscribed and listening.
>>
>> Tom
>>
>>
>
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