Re: Interfaces.C.String.Update

[Adam Beneschan <adam@irvine.com>]

On Nov 28, 7:55 am, awdorrin <awdor...@gmail.com> wrote:
> What is the suggested method to null terminate an Ada string being
> passed back to C via Interfaces.C.Strings.Update() ?
>
> I've been looking at the code for i-cstrin.adb, and it seems that by
> default that the procedure, when passing in an Ada String, uses To_C
> with Append_Null  set to False.

Right, that's actually in the RM.  B.3.1(49-50):

[49] procedure Update (Item   : in chars_ptr;
                       Offset : in size_t;
                       Str    : in String;
                       Check  : in Boolean := True);

[50] Equivalent to Update(Item, Offset, To_C(Str, Append_Nul =>
False), Check).

Since that's the language used in the RM, it seems most appropriate to
me that if you want to do the same kind of Update but *with* a null
character appended, you'd use the same code shown in the RM but with
Append_Nul => True.  It probably doesn't matter except as a matter of
style, but that's what I'd do (unless execution speed is *very*
critical, in which case a function call such as To_C that returns an
unconstrained array could involve too much overhead.  I doubt that's
true in your case).

                  -- Adam