Re: ada binding

[Szymon Guz <alpha@skynet.org.pl_WITHOUT>]

Martin Krischik napisał(a):
> Szymon Guz wrote:
> 
>> Maciej Sobczak napisa?(a):
>>> Szymon Guz wrote:
>>>
>>>> how to make an Ada binding for a "C++" class using this C layer ?
>>> Basically, if the C++ class is not a template, but just plain "classic"
>>> OO stuff, then you can write a wrapper around it in C, which will still
>>> be OO, but without the syntax sugar of real class. Something along this:
>>>
>>> // an existing C++ class:
>>> class MyClass
>>> {
>>> public:
>>>     void myFun();
>>> };
>>>
>>> // a C wrapper:
>>> extern "C"
>>> void * MyClass_new()
>>> {
>>>     return new MyClass;
>>> }
>>>
>>> extern "C"
>>> void MyClass_delete(void *p)
>>> {
>>>     delete static_cast<MyClass*>(p);
>>> }
>>>
>>> extern "C"
>>> void MyClass_myFun(void *vp)
>>> {
>>>     MyClass *mcp = static_cast<MyClass*>(vp);
>>>     mcp->myFun();
>>> }
>>>
>>> // and so on.
>>>
>>> Depending on the level of isolation that you want to achieve and the
>>> level of type safety that you want to retain, hiding the object behind
>>> void* might or might not be the best choice, but this is to give you the
>>> idea. Above, MyClass_new, MyClass_delete and MyClass_myFun are plain C
>>> functions (you can extract their declarations to separate header file)
>>> and you can interface them from just about any sensible language in
>>> existence and from Ada in particular.
>>>
>>>
>> OK, but what about using the class fields :
>>
>> class MyClass
>> {
>> public:
>>    int X;
>>    int *p_X;
>> }
>>
>> and what about inheriting this from the class in Ada, is it possible ?
> 
> If you are planning to inheriting  then you need to directly bind to the C++
> class. Only one compiler offers that (GNAT). Start reading here:
> 
> http://gcc.gnu.org/onlinedocs/gcc-4.0.2/gnat_rm/Pragma-CPP_005fClass.html
> 
> Martin

I know but I wander if I can do that using other compilers and with the 
middle layer written in C.

regards
Szymon Guz