Re: Question about writing message handling blocks

[Ellie White]

Hi Jeff,

Thank you so much for the helpful reply. So I hope you don't mind, but
I'm wondering if you could elaborate a little on how you would
implement using state variables to keep things in order, and how you
would go about registering the message handler late, as you said? I am
new to some of the terminology, so just want to make sure I implement
things correctly. Thanks tremendously for your time and help!

Cheers,
Ellie

On Thu, Jul 9, 2020 at 12:37 PM Jeff Long <willcode4@gmail.com> wrote:
>
> This is true, message handling is independent of stream handling. You may be 
> able to add state variables to keep things from happening out of order, and 
> _maybe_ you can register the message handler late?
>
> On Thu, Jul 9, 2020 at 12:01 PM Ellie White <elliewhite1420@gmail.com> wrote:
>>
>> Hey all,
>>
>> I've got a question about message handling in GNU Radio. I'm working on 
>> developing an out of tree module for controlling the Allen Array, and I'm 
>> currently working on a set of two blocks which are supposed to interact via 
>> messages, control.py and trackscan.py; note that "control" receives the 
>> messages and "trackscan" receives them. The code can be found here (please 
>> forgive the messiness, I've not had a chance to tidy it up yet): 
>> https://github.com/SETIatHCRO/gr-ata/tree/master/python
>>
>> I'm struggling because I can't seem to figure out why it is that when I put 
>> both of these blocks in a flowgraph, connect them, and run it -- the start 
>> function for the "control" blockseemingly gets called *before* the message 
>> handler function, and thus it acts like the obs_info dictionary is empty. 
>> (https://github.com/SETIatHCRO/gr-ata/blob/master/python/control.py#L54)  
>> Does anyone have any advice on this? This is my first time writing 
>> message-passing blocks so I am unfamiliar with the process. If I need to 
>> clarify any of the above please let me know and I'd be glad to. Thanks so 
>> much for your time and help -- I appreciate it!
>>
>> Cheers,
>> Ellie
>>
>> --
>> Ellie White
>> Co-Director, Open Source Radio Telescopes
>> Student at Marshall University
>> 304-654-9381
>> www.catseyeenterprises.net



-- 
Ellie White
Co-Director, Open Source Radio Telescopes
Student at Marshall University
304-654-9381
www.catseyeenterprises.net