Need help for constrained type

[Gerd <GerdM.O@t-online.de>]

Hello,

can someone help me? 

This is my problem:

I have a record containing a constrainted array. I can write it like this:


  type Mem_Array is array (Natural range <>) of Short_Integer;

  type Memory_Block (len : Natural) is
    record
      Start_Address : Mem_Addr;
      Block_Size : Natural;
      Usage_Info : Mem_Array (1..len);
    end record;

  mem : Memory_Block (2**16);  --  for example


But i would like the indices of Usage_Info running from 0..len - 1 (C-style). But when I write

  type Memory_Block (len : Natural) is
    record
      Start_Address : Mem_Addr;
      Block_Size : Natural;
      Usage_Info : Mem_Array (0..len-1);
    end record;

the compiler tells me that this is not allowed.

Is it possible to allocate "len" units, but address them from 0 .. len - 1?

How can I do this?

Thanks.