Block struct change

GNU Radio
1

Hi All,
I want know to why the block has been split into two class:
“block_name.cc”
and “block_name_impl.cc”, why do we need a virtual class, and use a
“_impl” to inherit it?
As we know, the older gnuradio just use a single class. Is there any
advantage of this change?

Thanks
Tiankun

2

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Hash: SHA1

Hi Tiankun,

the advantage lies in the fact that the user of your block just has to
look at the block_name.h (and also SWIG), and you can exchange,
implement, extend and subclass your implementation to your heart’s
delight in the block_name_impl.h. This simplifies SWIG wrapping a lot,
and thus has, at least for me, decreased development complexity
significantly.

Greetings,
Marcus

On 07.08.2014 14:15, Tiankun Hu wrote:

Hi All, I want know to why the block has been split into two class:
“block_name.cc” and “block_name_impl.cc”, why do we need a virtual
class, and use a “_impl” to inherit it? As we know, the older
gnuradio just use a single class. Is there any advantage of this
change?
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3

Yes :slight_smile:

4

Thanks Marcus,
My understand is we can define the member function that Pyton want to
know in block_name.h
and other thing that Python not interesting in block_name_impl.h, and
then swig.i only include block_name.h, so this will simplify SWIG’s
config, right?

在 2014年08月07日 20:18, Marcus Müller 写道:

significantly.

Greetings,
Marcus

On 07.08.2014 14:15, Tiankun Hu wrote:

Hi All, I want know to why the block has been split into two class:
“block_name.cc” and “block_name_impl.cc”, why do we need a virtual
class, and use a “_impl” to inherit it? As we know, the older
gnuradio just use a single class. Is there any advantage of this
change?

–
Thanks
Tiankun

5

Also, ABI stability.

M