Re: put of access type

[Rob Solomon <usenet@drrob1-noreply.com>]

>> >You probably meant the address of the pointed object. Here you go. Let Ptr
>> >be a pointer to some object
>>
>> >(with System.Storage_Elements; �use System.Storage_Elements;)
>>
>> > � Integer_Address'Image (To_Integer (Ptr.all'Address)));
>>
>> >Ptr.all'Address is the address of the object. To_Integer converts the
>> >address to a plain integer type (Integer_Address defined in
>> >System.Storage_Elements). This type can be output as any other.
>>
>> I am trying to understand this. �
>>
>> Back when I learned Modula-2, I learned that pointer types are
>> assignment compatible with System.Address and I understand them as
>> being the same thing. �They �differ in context, not value.
>>
>> I see that access types are being used the same as pointer types, but
>> if I understand correctly, are actually quite different. �But I don't
>> understand how. �ie, how are access types and pointers different?
>
>For simple types (integer; simple records) there's probably no
>difference. For types with constraints/discriminants, bets are off:
>consider
>
>  S : access String := "foo";
>
>S will most likely (this is compiler-dependent) *not* point to the 'f'
>in "foo"; it might point to a structure containing
>
>   4-byte integer, lower bound of string (= 1)
>   4-byte integer, upper bound of string (= 3)
>   1-byte character = f
>   1-byte character = o
>   1-byte character = o
>
>> What is the difference between integer_address and address?
>
>integer_address is some sort of integer, with 'image, "=", "-" etc;
>address is private, with no such operations (it does have comparators;
>see package System).
>
>integer_address'image is going to be up to about 10 (32-bit addresses)
>or 20 (64-bit addresses) characters long, and you are assigning it to
>a string of length 255; that won't work.

This is what I came up with, that works.  But I have another question,
to follow the code:

procedure adr is

   type card32 is mod 4_294_967_296;
   package card32_IO is new Ada.Text_IO.Modular_IO(card32);


   X : aliased Integer := 1;
   c,k : card32 := 0;

   P1,P2,P3 : Access Integer;
   Str,S : String(1..255);
   begin
   P1 := X'Access;
   P2 := P1;
   P3 := new integer;

Ada.Strings.Fixed.Move(Integer_Address'Image(To_Integer(P1.all'Address)),Str);
   Move(System.Address_Image(P1.all'address),s);
   C   :=
card32'value(Integer_Address'Image(To_Integer(P2.all'Address)));
   K   :=
card32'value(Integer_Address'Image(To_Integer(P3.all'Address)));
   put("Str = ");
   put(Str);
   new_line;
   put("s = ");
   put(s);
   put("C = ");
   Card32_io.put(c);
   new_line;
   put("K = ");
   Card32_io.put(k);
   new_line;
   end adr;

My question is that the value of Str and S should be equal, after
converting  hex <-> decimal.  They are not.  I am getting this as the
relevent output
Str = 3215841220
S = BFADD7C4

These numbers are not equal, according to my conversion.

What am I missing?