Re: type Foo_ptr in new void*;

[tmoran@acm.org]

> Foo *foo_new(some args);
> void foo_delete(Foo*);
> void foo_some_operation(Foo*,some args);
> xyz foo_some_function(Foo*,some args);
>
> How should I typedef Foo* ?

  Presumably you "typedef Foo" in the C code in normal C style.
If you are wondering how to describe these C functions in Ada,
from the implementation advice in ARM B.3(67 .. 70), as given
at www.adapower.com:

4.An Ada in parameter of an access-to-object type with designated type
  T is passed as a t* argument to a C function, where t is the C type
  corresponding to the Ada type T.
5.An Ada access T parameter, or an Ada out or in out parameter of an
  elementary type T, is passed as a t* argument to a C function, where t
  is the C type corresponding to the Ada type T. In the case of an
  elementary out or in out parameter, a pointer to a temporary copy is
  used to preserve by-copy semantics.
6.An Ada parameter of a record type T, of any mode, is passed as a t*
  argument to a C function, where t is the C struct corresponding to the
  Ada type T.
7.An Ada parameter of an array type with component type T, of any
  mode, is passed as a t* argument to a C function, where t is the C
  type corresponding to the Ada type T.

So given
  type Foo is record ...
  type Foo_Pointer is access Foo;

> Foo *foo_new(some args);
    function foo_new(someargs : sometype) return Foo_Pointer;
> void foo_delete(Foo*);
    procedure foo_delete(Param : in out Foo);
> void foo_some_operation(Foo*,some args);
    procedure foo_some_operation(Param : in out Foo; someargs : in sometype);
> xyz foo_some_function(Foo*,some args);
    function foo_some_function(P : Foo_Pointer; someargs : sometype)
      return xyz;

There are other ways, for instance
    procedure foo_delete(Param : access Foo);