Re: [Discuss-gnuradio] using virtual member functions

[Martin Braun]

When you 'make' a block, it actually returns you a _impl version of the 
class, even though only the abstract class is declared publically. All 
the methods are actually defined in the _impl, where also the members 
reside.

If you're having trouble understanding the polymorphism concepts, I 
suggest having another look at some C++ literature. If it's the actual 
GNU Radio block design, have another look at examples of blocks (e.g. in 
gr-blocks) to see how the abstract methods interact with their definitions.

Cheers,
M

On 13.03.2015 06:15, Mostafa Alizadeh wrote:
> Hello all,
>
> I'm about to use member functions of the abstract base class of qtgui
> classes to adjust visualization parameters such as "set_title",
> "set_line_label" etc.
>
> There is an explanation of virtual based classes in [1]. So it's
> possible to use pure virtual functions by the derived classes.
>
> When we're in GNURadio, there is an abstract class and an implementation
> class which is derived from the abstract class. So I expect to be able
> of using the pure virtual functions declared in abstract class by having
> a pointer of the implementation class. However the members aren't
> accessible. What can I do to use them?
>
> Best,
> Mostafa
>
> [1] http://www.cplusplus.com/doc/tutorial/polymorphism/
>
>
>
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