Converting a C/C++ statement to Ada

Converting a C/C++ statement to Ada

[ldries46]

Can anyone tell me the Ada equivalent for the following C/C++ statement

typedef void (*Apple) (Pair *two_side, pointer_type user_data,  Error_type 
*error);

I am just trying to convert a routine that I can use.

L. Dries 

Re: Converting a C/C++ statement to Ada

[Simon Wright]

"ldries46" <bertus.dries@planet.nl> writes:

> Can anyone tell me the Ada equivalent for the following C/C++
> statement
>
> typedef void (*Apple) (Pair *two_side, pointer_type user_data,
> Error_type *error);

I think it's something like

   type Apple is access procedure (two_side : access Pair;
                                   user_data : ?;
                                   error : access Error_type);

but of course the parameters may well not need to be accesses.

Re: Converting a C/C++ statement to Ada

[Adam Beneschan]

On Monday, February 11, 2013 9:14:25 AM UTC-8, Simon Wright wrote:
> "ldries46" writes:
> 
> > Can anyone tell me the Ada equivalent for the following C/C++
> > statement
> 
> > typedef void (*Apple) (Pair *two_side, pointer_type user_data,
> > Error_type *error);
> 
> I think it's something like
> 
>    type Apple is access procedure (two_side : access Pair; 
>                                    user_data : ?; 
>                                    error : access Error_type);
> 
> but of course the parameters may well not need to be accesses.

Right.  Unless the C/C++ code actually does something with the pointer values themselves (such as copying two_side or error into some global pointer variable that gets used later), then they probably should not be accesses, but rather just "in Pair", "out Pair", or "in out Pair" (and similarly for Error_type) depending on whether the Pair or its components are read, written, or both.

                             -- Adam

Re: Converting a C/C++ statement to Ada

[ldries46]

I am happy with this answer, thanks

L. Dries

"Adam Beneschan"  schreef in bericht 
news:eff6a8c1-f589-46b1-9a4e-d4d9a17d9e16@googlegroups.com...

On Monday, February 11, 2013 9:14:25 AM UTC-8, Simon Wright wrote:
> "ldries46" writes:
>
> > Can anyone tell me the Ada equivalent for the following C/C++
> > statement
>
> > typedef void (*Apple) (Pair *two_side, pointer_type user_data,
> > Error_type *error);
>
> I think it's something like
>
>    type Apple is access procedure (two_side : access Pair;
>                                    user_data : ?;
>                                    error : access Error_type);
>
> but of course the parameters may well not need to be accesses.

Right.  Unless the C/C++ code actually does something with the pointer 
values themselves (such as copying two_side or error into some global 
pointer variable that gets used later), then they probably should not be 
accesses, but rather just "in Pair", "out Pair", or "in out Pair" (and 
similarly for Error_type) depending on whether the Pair or its components 
are read, written, or both.

                             -- Adam 

Re: Converting a C/C++ statement to Ada

[Quentin Ochem]

> 
> I am just trying to convert a routine that I can use.
> 

Are you trying to translate code from Ada to C++, or just to interface it?

In the latter case, the gcc switch -fdump-ada-specs does the job for you (http://docs.adacore.com/gnat-unw-docs/html/gnat_ugn_29.html#SEC298)