Re: Ada to C++ communication under NT4.0

[Gene Ouye <geneo@rational.please_no_unsolicited_mail.com>]

FYI, Rational Apex Ada NT also uses the MS object file format and can
link with MSVC++ code.  However, as you mention below, DLLs are another
way to make multi-language applications in Windows.  I have found most
people find it simpler to create Ada DLLs (which you can do with Apex)
which can then called by any language you choose.

Gene Ouye <g.e.n.e.o.@.r.a.t.i.o.n.a.l...c.o.m>


Stephen Leake wrote:
 [...]
> There are two issues in combining C++ and Ada into a single executable:
> object file format and elaboration/finalization.
> 
> The current fully supported version of the GNAT compiler (3.11?)
> supports the Microsoft object format, so it can link C++ compiled with
> MS C++ with Ada compiled by GNAT. The current public version of GNAT
> (3.10) can't do this. However, ObjectAda from Aonix uses the MS object
> file format for Ada code; it can link with MS C++. Note that Borland
> uses a different object file format, and can't link with any of these.
> 
> Another way around the object file format problem is to make DLLs. In my
> current application, I use ObjectAda to make a DLL, and call it from
> Borland C++. GNAT can also make DLLs.
> 
> The elaboration/finalization problem is solved by explicitly calling the
> elaboration and finalization code that is normally called by "main". In
> general, you can have either an Ada main that explicitly calls the C++
> stuff, or a C++ main that explicitly calls the Ada stuff. The GNAT
> user's guide has good instructions on how to call the GNAT
> elaboration/finalization code.
> 
> Multi-language programming is the best way to introduce people to Ada!
> 
> -- Stephe