Re: help with pointerproblem.

[Mats Weber <Mats.Weber@elca-matrix.ch>]

Roger Carlsson wrote:
 
> I'm writing a program in ada95 with opengl on W95.
> 
> I have the following definitions in GL.ads:
> 
> type GLubyte     is new C.unsigned_char;
> type GLpointer   is access all GLubyte;  -- our substitute for "void *"

The substibute for void * in Ada is called System.Address.

Just write your C subporgrams in Ada with System.Address as parameters, e.g:

   function example (X : System.Address) return Interfaces.C.Int;

   pragma Import (C, example);

   ...

   Z : VertexArray(...);

   Result := example(Z'Address);

I have always done it this way and it works great will all compilers I have used.

Another approach is using access parameters (you get better type checking this
way) but I'll let someone else decribe that (I have never used it myself).