[PD] C++ for reusable dsp lib - or better use C?

[Hans-Christoph Steiner]

On Mar 2, 2012, at 4:32 AM, katja wrote:

> On Wed, Feb 29, 2012 at 9:17 PM, Thomas Grill <gr at grrrr.org> wrote:
>> 
>> Hi Katja,
>> maybe i'm chiming in too late, but i would definitely use C++ programming for
>> whatever i do in the C-world.
>> It's no problem to make the public API (exported functions) C-style then to avoid
>> various hassles.
>> If your library is just a wrapper it might not be worth to live in both worlds, but if it's
>> a substantial amount of code, i would go for C++ with a C interface.
>> gr~~~
>> 
> 
> 
> Thanks for your recommendation, Thomas. Mathieu and IOhannes did
> similar suggestions.
> 
> Can anyone point me to an example of a C++ lib with C API, in the
> field of dsp? Not sure if I can think of the best way how to do it.
> 
> As I see it now, a C++ class could be instantiated and accessed from C like so:
> 
> - define an extern "C" wrapper which calls a class constructor and
> returns the pointer to the instantiated object.
> 
> - define extern "C" accessor wrappers which take the object pointer as
> their first argument, like how you would access data in C structs.
> 
> - via the object pointer, the extern "C" accessor wrappers can call
> class member functions to access the class private data in C++ style.
> 
> 
> How about function call overhead? For constructor and destructor no
> problem of course, but accessor wrappers will be called often, in fact
> it doubles the number of function calls for external access.
> 

The C++ ABI compatibility problems are not the only thing that make C++ hard to deploy.  On limited platforms like Android, they include limited C++ support, like no exceptions and other stuff.  Its still possible to write portable C++, if you track all of these various issues across the platforms you want to support.

.hc

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