Re: How pass a "null" as a parameter of anonymous access type

["Mark Lundquist" <mark@rational.com>]

Freddy <Alfred.Hilscher.X@t-online.de> wrote in message
news:3ABE6443.4119AB52@t-online.de...
> Thanks. I've tried it, but at runtime I always get a constraint_error
> (GNAT seems to check the passing of "null" values).

Yes -- as any correct Ada compiler must do!

The value "null" just does not exist for the type of the parameter.

Now, you might be able use "pragma Suppress (Access_Check)" to defeat this.

But it seems like any Ada binding to C that uses access parameters for
things that you are supposed to be able to pass a null value is in error,
plain and simple!

Why can't you write your own corrected version of the subprogram
declaration, write your own "pragma Import (C, ..." for it, and use the
corrected version instead of the erroneous one?  Then you're not actually
"changing" it, just not using it... and instead using something else that is
very similar... :-)

Mark Lundquist
Rational Software