Re: More C

[Jeff Carter <jrcarter010@earthlink.net>]

Jan Kroken wrote:
> I have the following C structs
> 
> typedef struct {
>         Uint8 r;
>         Uint8 g;
>         Uint8 b;
>         Uint8 unused;
> } SDL_Color;
> 
> typedef struct {
>         int       ncolors; /* number of colors */
>         SDL_Color *colors; /* array of colors */
> } SDL_Palette;
> 
> and have included them in Ada as
> 
> type SDL_Color is record
>         R, G, B, Unused: C.Unsigned_Char;
> end record;

Note the comment that this is an array. The best way to treat this in
Ada is probably as an array:

type SDL_Palette is record
   Num_Colors : C.Int;
   Address_Of_Color_Array : System.Address;
end record;

Given:

   Palette : SDL_Palette;

containing data from C, use

type Color_Set is array (C.Int range <>) of SDL_Color;

Colors : Color_Set (1 .. Palette.Num_Colors);
for Colors'Address use Palette.Address_Of_Color_Array;

That only answers 1 of your 2 questions, I'm afraid.

-- 
Jeff Carter
"We burst our pimples at you."
Monty Python & the Holy Grail