Re: Ada array vs C pointer (call by reference)

[Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de>]

Maciej Sobczak wrote:
> On 27 Cze, 16:43, Georg Bauhaus <rm.tsoh.plus-
> bug.bauh...@maps.futureapps.de> wrote:
> 
>>> Is there any implementation where Interfaces.C.int has different
>>> properties than Integer?
...
>> procedure Cint is
>>    use Interfaces;
>>    use type C.int;
>>
>>    X: C.int;
>> begin
>>    X := C.int'last;
>>    X := X + 1;
>> end;
> 
> CONSTRAINT_ERROR - overflow check failed.
> I get the same with Integer.
> 
> What is the difference then?

I should have made the example adress the difference
between the Ada types Integer and C.int as a representative
of C's int behavior.
In code that uses C integers I'll see C.int used, and
hence meaningfully different types. This points me to
different behavior on the C side even when inside Ada
it makes no difference:

int inc(int x) { return x + 1; }

with Interfaces.C, Ada.Text_IO;

procedure Cint is
   use Interfaces;
   use type C.int;

   function C_inc(X: C.int) return C.int;
   pragma import(C, C_inc, "inc");

   X: C.int;
begin
   X := C.int'last;
   X := C_inc(X);
   Ada.Text_IO.Put_Line(C.int'image(X));
end;

prompt>cint
-2147483648