Re: Question about interfacing C and Ada95

[Robert Dewar <robert_dewar@my-deja.com>]

In article <806ud0$lu1$1@trog.dera.gov.uk>,
  "Hovers" <hovers@dera.gov.uk> wrote:
> if I have a c routine that returns more than one value what is
thge best way
> to interface to Ada with it.
>
> e.g. int getX ( void **instance, int *float );
>
> we have recoded the c to this as Ada funcs do not allow more
> than one return

Both Ada and C allow exactly one value to be returned.

Both Ada and C allow pointers to be passed by value, allowing
the called subprogram (function or procedure in Ada) to modify
the calling parameter.

Ada in addition for procedures only, has a feature (out
parameters) that is not allowed in C at all.

But it does not seem there is any significant problem here!

Yes, it would be nice if you could model pointer parameters in
C with out parameters in functions in Ada, but you can't and
you certainly don't need to. Just call the function as you
would in C, passing a pointer if the parameter is of a pointer
type.

If necessary (but please ONLY if necessary) use aliased and
'Access to pass a pointer to a declared variable.





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