Re: Interfaces.C and void *

[Tucker Taft <stt@averstar.com>]

Florian Weimer wrote:
> 
> Recently, I wrote a binding for a C library which provides an abstract
> data type and completely hides the underlying representation of the type
> (i.e., all the public routines work on pointers to void).
> 
> Is there really no portable equivalent of a C void * in Interfaces.C?
> I used Interfaces.C.Strings.chars_ptr, which should be quite portable in
> practice, but AFAIK, ISO C doesn't require the representation of void *
> and char * to be identical.

Adding a void_ptr to Interfaces.C would seem like a reasonable addendum
to the standard.  In the interim, I would define a type in your own
code, such as:
    type Void_Ptr is private;
   ...
    type Void_Ptr is new System.Address;

This way, you will only need to change the definition in one place
if that becomes necessary (which I doubt, in practice).

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA