Re: Interfaces.C

[nebbe@lglsun.epfl.ch (Robb Nebbe)]

In article <395o3q$2j1@wynkyn.ecs.soton.ac.uk>, kst@ecs.soton.ac.uk (Ken Thomas) writes:
|> I am attempting to write an Ada9X interface for a C function
|> with specification
|> 
|> void foo(int *a, int l)
|> 
|> the aim being to pass an integer array to the C-function. What is the
|> correct usage of the package Interfaces.C and its children?
|> 

If you just want to pass parameters to the C function you would write:

  type Int_Array is array( Natural range <> ) of C.int
  -- the range could be anything but C will treat it as starting at 0

  procedure foo( a : in Int_Array; l : in C.int );
  pragma Import( C, foo );


The array a will be passed by reference and l by value automatically.
The rules for how parameters are passed to a C program are defined
in Ada9x making it easy to abstract away from C's low-level calling
interface.

- Robb Nebbe