Re: Pass by reference

[Simon Wright <simon@pushface.org>]

"Steve" <nospam_steved94@comcast.net> writes:

> I am only aware of one (obscure) case in Ada where passing by
> reference versus passing by value makes a difference.  It has come
> up on this newsgroup before.

I had (in the full view)

  type Socket is record
     Handle : Interfaces.C.int;
  end record;

and, on failure, my Read operation woudl close() the Handle in its "in
out" Socket parameter, set it to -1, and raise an exception.

But the actual Socket didn't get altered, because it wasn't by-reference.

So I had to make it a tagged type (couldn't be limited, for some
reason I forget now).

-- 
Simon Wright                               100% Ada, no bugs.