Re: pragma Pack does not work on GNAT 5.01a for Redhat Linux.

[Adam Beneschan <adam@irvine.com>]

On Jun 19, 6:16 am, petter_frykl...@hotmail.com wrote:
> The Size of the following record is 112 on Linux, but 104 on Solaris.
>
> type Something is record
>    A : Packed_16;
>    B : Packed_8;
>    C : Packed_8;
>    D : Packed_8;
>    E : Packed_32;
>    F : Packed_32;
> end record;
> pragma Pack (Something);
>
> Where
>
> type Packed_Byte is mod 2 **8;
> for Packed_Byte'Size use 8;
>
> type Packed_Bytes is array (Natural range <>) of Packed_Byte;
> for Packed_Bytes'Alignment use 1;
> for Packed_Bytes'Component_Size use Packed_Byte'Size;
>
> type Packed_8 is new Packed_Bytes (0 .. 0);
> for Packed_8'Size use 8;
>
> and similar. Why is pragma Pack ignored?

Strange... I get 104 when I try it on Linux.  I could be using a
different version of GNAT, though.

                          -- Adam

package Test109pak is

    type Packed_Byte is mod 2 **8;
    for Packed_Byte'Size use 8;

    type Packed_Bytes is array (Natural range <>) of Packed_Byte;
    for Packed_Bytes'Alignment use 1;
    for Packed_Bytes'Component_Size use Packed_Byte'Size;

    type Packed_8 is new Packed_Bytes (0 .. 0);
    for Packed_8'Size use 8;

    type Packed_16 is new Packed_Bytes (0 .. 1);
    for Packed_16'Size use 16;

    type Packed_32 is new Packed_Bytes (0 .. 3);
    for Packed_32'Size use 32;

    type Something is record
       A : Packed_16;
       B : Packed_8;
       C : Packed_8;
       D : Packed_8;
       E : Packed_32;
       F : Packed_32;
    end record;
    pragma Pack (Something);

end Test109pak;

with Test109pak;
with Text_IO;
procedure Test109 is
begin
    Text_IO.Put_Line ("Size is " & Integer'Image
(Test109pak.Something'Size));
end Test109;