Re: Lack of formal syntax undermines Ada

Gary Scott <garylscott@[EMAIL PROTECTED]
> writes:

> Sorry, non-Ada nube type question:  How is inter-language calling of
> functions that do allow inout and out arguments handled (say calling a C
> API)?

Well, C doesn't have anything like Ada's 'out' or 'in out'.

You can pass a pointer in C, and you can do the same in Ada:

    function F (X: access Integer) return Integer;
    pragma Im****t (C, F);

>...I assume the restriction only applies to intra-language calls.

No, that assumption is wrong.  An Ada function declaration cannot use
'out' or 'in out'.  That's true even if there's a pragma Im****t,
so the body of the function is in some other language.

If that other language sup****ts something like Ada's 'in out',
well, too bad.  The compiler writer will have to invent
some other way to map that language onto what's allowed in Ada.

>...It
> seems like could create some messiness if the compiler always assumed
> only IN arguments in functions.

Yes, it is an annoying restriction (whether or not you're
interfacing to C).

- Bob