Re: Calling C++ from Ada

[Jeffrey Creem <jeff@thecreems.com>]

Yves Bailly wrote:
> Hello all,
> 
> I'm trying to use C++ classes from an Ada program. Searching around, I
> found some examples, but none implying a non-default constructor.
> I tried some advices found in
> http://www.pegasoft.ca/resources/boblap/19.html#19.5, which work well,
> but it seems one can only use default constructors. Using various versions
> of GNAT (including the one coming with the latest GCC 4.2.0), when trying
> to use the pragma CPP_Constructor with a function taking more than zero
> parameters, I get this message :
> imported.ads:36:27: non-default constructors not implemented
> 
> Does anyone have any clue about this ?
> 
> Thanks and best regards,
> 
>     Yves Bailly
> 

Direct interface to C++ from Ada is outside the scope of the Ada (at 
least 95) LRM. GNAT has some vendor specific pragmas that can be used 
but I have never heard of any widespread use of these pragmas in any 
publically avaialble code.

There is a paper on the topic being presented at the GCC summit this summer

http://www.gccsummit.org/2006/view_abstract.php?content_key=26

In any case, outside of something heavy like an ORB or vendor specific 
such as GNATCOM I have not seen anything that looks to promising in this 
area yet.

You probably need to interface to it the same way a C programmer would - 
with non classed based externs.