Re: Help with gnat storage error

[Stephen Leake <Stephen.Leake@gsfc.nasa.gov>]

Myriam Witt wrote:
> I'm using gnat's binary distribution
> gnat-3.09-sparc-sun-solaris2.4-bin.tar.gz
> on a SUN Ultra 2, Solaris 2.5.1 (anyone knows about a 2.5.1 binary?).
> 
> During compile-/linktime I get some messages
> 'warning: creation of object of this type may raise Storage_Error'
> from code like
> ---
>    type T_Polygon_XYZ (Max_Punkte: Natural := 1) is
>       record
>         Punkte : Natural   := Max_Punkte;  -- Anzahl der Polygonpunkte
>         X : T_Vector_Float(1..Max_Punkte) := (others => 0.0);
>         Y : T_Vector_Float(1..Max_Punkte) := (others => 0.0);
>         Z : T_Vector_Float(1..Max_Punkte) := (others => 0.0);
>       end record;
> 
> where
> 
>    type  T_Vector_Float   is array(integer range <>) of Float;

This is because you might declare:

A : T_Polygon_XYZ (Natural'last);

which would use all of memory (or at least a lot of it!). You should use
a smaller range for Max_Punkte:

type Max_Punkte_Type is range 1 .. 1000;
type T_Polygon_XYZ (Max_Punkte: Max_Punkte_Type := 1) is

You have to pick a reasonable max value, but that is usually not hard.
If you really can not pick a max value, you should be using dynamic
allocation, and a linked list or other structure instead of an array.

-- 
- Stephe