Re: [Discuss-gnuradio] Message Passing

[Martin Braun]

On 14.05.2014 08:11, Activecat wrote:
> Dear gurus,
>
> I am learning gnuradio Message Passing feature, but couldn't get
> desirable result.
> The Message seems published successfully, but not subscribed by the
> Message receiver.
> How to correct the error ..?

Just to make sure: You did connect the ports in your flow graph?

That said, I've seen something like this recently. Maybe there's a 
bug... needs investigating.

M
> The message sender block:
>
>      // constructor
>          message_source1_impl::message_source1_impl()
>            : gr::sync_block("message_source1",
>                    gr::io_signature::make(0, 0, 0),
>                    gr::io_signature::make( 1, 1, sizeof(int)) )
>          {
>              message_port_register_out( pmt::mp("print") );
>          }
>
>          // send_message1
>          void
>          message_source1_impl::send_message1()
>          {
>              std::cout << "message_source1_impl::send_message():
> invoked" << std::endl;
>              pmt::pmt_t str0 = pmt::string_to_symbol(
> std::string("Welcome 2014"));
>              message_port_pub( pmt::mp("print"), str0 );
>          }
>
>          // work
>          int
>          message_source1_impl::work(int noutput_items,
>                    gr_vector_const_void_star &input_items,
>                    gr_vector_void_star &output_items)
>          {
>              int *out = (int *) output_items[0];
>              for (int i=0; i < noutput_items; i++)
>                  out[i] = (i+1) * (i+1);
>
>              send_message1();
>              return noutput_items;
>          }
>
>
>
> The message receiver block:
>
>      // constructor
>          message_sink1_impl::message_sink1_impl()
>            : gr::sync_block("message_sink1",
>                    gr::io_signature::make(0, 0, 0),
>                    gr::io_signature::make( 1, 1, sizeof(int)) )
>          {
>              message_port_register_in( pmt::mp("print") );
>              set_msg_handler( pmt::mp("print"), boost::bind(
> &message_sink1_impl::handler1, this, _1 ) );
>          }
>
>          // message handler
>          void
>          message_sink1_impl::handler1( pmt::pmt_t myMessage )
>          {
>              std::cout << "message_sink1_impl::handler1():  invoked" <<
> std::endl;
>              pmt::print( myMessage );
>          }
>
>          // work
>          int
>          message_sink1_impl::work(int noutput_items,
>                    gr_vector_const_void_star &input_items,
>                    gr_vector_void_star &output_items)
>          {
>              int *out = (int *) output_items[0];
>              for (int i=0; i < noutput_items; i++)
>                  out[i] = i+1;
>
>              return noutput_items;
>          }
>
>
>
> Flow graph execution output:
>      Executing: "/home/mmkk/gnuradio/gr-activecat/apps/top_block.py"
>      message_source1_impl::send_message():  invoked
>      message_source1_impl::send_message():  invoked
>      message_source1_impl::send_message():  invoked
>      message_source1_impl::send_message():  invoked
>      message_source1_impl::send_message():  invoked
>
>
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