Re: Address representation clause is getting 0

["Luke A. Guest" <laguest@n_o_p_o_r_k_a_n_d_h_a_m.abyss2.demon.co.uk>]

On Wed, 31 Dec 2003 15:48:36 -0600, Randy Brukardt wrote:

> "Luke A. Guest" <laguest@n_o_p_o_r_k_a_n_d_h_a_m.abyss2.demon.co.uk> wrote
> in message
> news:pan.2003.12.31.13.53.00.912339@n_o_p_o_r_k_a_n_d_h_a_m.abyss2.demon.co.
> uk...
>> I think that this is an elaboration problem. Now as I don't have a runtime
>> or any tools, I need to rely on my own code (think of this as an OS
>> kernel).
>>
>> Does anyone know what I need to do to get this to work?
> 
> Ada access objects are initialized to null by default. The object to which
> you applied the address clause is thus getting initialized. You have to tell
> the compiler not to do that, and the way you do that is to give a pragma
> Import. Something like
> 
>     pragma Import (SB_Block, Ada);
> 
> will suppress the initialization, allowing you to read the data.

Not only this, but I had to change all To_Address(*) to
System'To_Address(*) so that I had a static address rather than a function
call.

Also, by adding:

pragma Restrictions(No_Elaboration_Code);

to the start of my spec, I didn't have to call any elaboration code ;-)

All this worked and I can now dump a character to the screen, yay!

Thanks,
Luke.