Re: [Discuss-gnuradio] Using GRC generated python code inside a C++ code

I managed to do it by creating an OOT module. I implemented my client C++ code in the block impl.cc file and also added my other source files. I had some problems in that area, but then I managed to solve it, as I discussed in another thread. I implemented messaging passing, created a message output port in my block and used the control port of the UHD:USRP sink block. It works like a charm. With just a couple of commands from my server, I can now control the USRP which is at the client side, using TCP.

Pranav Padalkar

Fraunhofer-Institut für Eingebettete Systeme und Kommunikationstechnik ESK

From: Discuss-gnuradio <discuss-gnuradio-bounces+address@hidden> on behalf of Pranav Padalkar <address@hidden>
Sent: Monday, August 22, 2016 9:48 AM
To: Marcus Müller; address@hidden
Subject: Re: [Discuss-gnuradio] Using GRC generated python code inside a C++ code

Thanks a lot Marcus,

Thanks for pointing me towards feval and message passing. We have decided to implement an OOT module, which will then control some of the blocks from the flowgraph. Message passing will definitely come handy. I will let you know how it works.

Regards,

Pranav.

From: Discuss-gnuradio <discuss-gnuradio-bounces+address@hidden> on behalf of Marcus Müller <address@hidden>
Sent: Friday, August 19, 2016 3:21 PM
To: address@hidden
Subject: Re: [Discuss-gnuradio] Using GRC generated python code inside a C++ code

have a look at the feval class [1]; it's a way to call python code from C++ land, and vice versa.

Be very careful about multithreading – all the GNU Radio blocks run in their own thread, so does the GNU Radio scheduler, and just executing python while python is executing might have interesting effects!

My approach would probably be to write a Python sync block with 0 in and 0 stream outputs, and connect that to the blocks you want to control with message passing as far as possible (UHD source has a command message interface, so this would work nicely), and call the python top_block's set_variable() methods only when impossible to avoid. In fact, things can be pretty easy: The ZeroMQ message sources can accept zeromq messages, and you could directly connect them to the message control ports of the blocks, so no need to write your own GNU Radio blocks at all; just use #include <pmt/pmt.h>/pmt::pmt_t and ZeroMQ in your C++ code to send messages directly across network/IPC/intra-process queues to your Flow graph.

Best regards,

Marcus

[1] http://gnuradio.org/doc/doxygen/classgr_1_1feval.html

On 19.08.2016 14:07, Pranav Padalkar wrote:

Hi Sebastian,

Thanks for your reply. In the meanwhile I was going through some documents on embedding Python in C++. I liked the idea of having a python code embedded in my client c++ code. But I think access data variables from the gnuradio code (for eg centre freq, bw, gain, etc) will be difficult. Because I want to set them from my client c++ code. I am still searching for other options, but so far python embedding seems good. Will let you know how it works.

If others have any other options, please let me know.

Thanks!

Pranav
From: Koslowski, Sebastian (CEL) <address@hidden>
Sent: Friday, August 19, 2016 1:15 PM
To: Pranav Padalkar; address@hidden
Subject: Re: [Discuss-gnuradio] Using GRC generated python code inside a C++ code
Well, there a number of options. Given your description its hard to say which one is best.
Aside from maintainability and flexibility of the system, it really depends on the required interaction between the components.
You could
    - re-implement the fg in C++.
    - create Python bindings for your C++ client (e.g. with swig) and do the integration/coupling in Python (outside of the fg)
    - embed Python in your C++ client (https://docs.python.org/2/extending/embedding.html)
    - simply run the Python interpreter as a sub-process if the C++ client

If you choose 2, 3 or anything not the list let me know how it worked out =)

Sebastian

On 08/19/2016 10:02 AM, Pranav Padalkar wrote:
Hello,

I have a GRC generated python code. I also wrote a server-client code in C++. I want to implement the client-code along with the GNU python code. The essence is that I want to a run a client C++ code, which will call the python code in a thread and start the USRP to receive/transmit data, and continue performing it's own process in another thread. I am not sure how I could go about this. I also considered implementing the client C++ code as module in GNU radio and use it in the flow graph. But I think that's not how a client background code should run.

Any thoughts on this matter would be helpful. Thanks in advance.

Best Regards,

Pranav Padalkar
Fraunhofer-Institut für Eingebettete Systeme und Kommunikationstechnik ESK

Hansastraße 32 | 80686 München

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From:	Pranav Padalkar
Subject:	Re: [Discuss-gnuradio] Using GRC generated python code inside a C++ code
Date:	Tue, 30 Aug 2016 08:30:41 +0000