clipka wrote:
> Darren New schrieb:
>>
>> What I'm doing right now is declaring
>> struct _IDirectFB; struct _IDirectFBFont; ...
>> class dfbScreen {
>>   struct _IDirectFB* dfb;
>>   struct _IDirectFBFont* font;
>>   ...
>> }
>>
>> But that seems wrong, given that I have to grope around in someone 
>> else's headers to pull out private declarations to make it possible to 
>> compile a header that doesn't depend on those declarations.
> 
> Yes, that's why you normally /do/ include the headers... after all, 
> that's what they are for.

It seems wrong that I should have to expose the DirectFB declarations to 
classes that don't care about the directfb declarations, simply because the 
private parts of one of the classes they use has a pointer to something in 
the directfb libs. That's what's the "seems wrong" part.


> I'm not sure, but you might also be able to directly use
>     struct IDirectFB;

IDirectFB isn't a struct or a class. It's a typedef. Therein lies the problem.

> Unfortunately, C++ doesn't natively make a good job at separating 
> interface from implementation (the bane of allowing direct access to 
> data members, and "inlining" of classes as data members).

Yeah. Plus having to declare everything *and* define it.

> Speaking of interfaces, you might make dfbScreen abstract (serving as 
> what would usually be declared as an interface in Java), so that you can 
> keep the actual implementation of it in the background - private data 
> members included.

What I did for the "real" library interface was to have a Player and a 
Player_p object, and the Player.h forward-declared Player_p and the 
Player.cpp included the actual definition. It's just an extra level of 
indirection and another header file and such, which seemed unnecessary for a 
unit-test helper function. (Only the fact that I expect to have to do unit 
tests for multiple GUI bits drove me to make it separate from the unit tests 
to start with, and then I got sidetracked down to figuring out how to do it 
better. :-)

-- 
   Darren New, San Diego CA, USA (PST)
   I ordered stamps from Zazzle that read "Place Stamp Here".

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