Interfacing to C and types visible to Ada

Maciej Sobczak wrote:
Imagine a C API that uses the int type to express something that does
not have any dedicated domain. In other words, it is not "number of
apples", not "height in meters", not "hotel room number", etc., it is
just plain "integer", which meaning can depend on how the given
library is actually used.

How about making the Ada binding generic, e.g.:

generic
type Integer_Type is range <>;
package Ada_Binding is
function Foo return Integer_Type;
end Ada_Binding;

with Interfaces.C;
package body Ada_Binding is
function Foo return Integer_Type is
function Internal return Interfaces.C.int;
pragma Import (C, Internal, "foo");
begin
return Integer_Type (Internal);
end Foo;
end Ada_Binding;

This way, the user of the library specifies the particular meaning of
the "integers" in each case. This design makes it possible to create
several instances of Ada_Binding with different meanings and then
benefit from Ada's strong typing.

--
Ludovic Brenta.