Re: How to convert record?

["Smark" <not.provided@all.com>]

"Ted Dennison" <dennison@telepath.com> wrote in message
news:%oWB7.96$xS6.155@www.newsranger.com...
> In article <mailman.1004014779.9400.comp.lang.ada@ada.eu.org>, sk says...
> >
> >-- ... Use 'Size on a _variable_ of that type, not the type itself,
> >-- and divide by System.Storage_Unit (i.e., 8). ...
> >
> >Why variable and NOT type ?
>
> Because the type will return the number of bits it could theoreticly fit
into,
> not the number it takes up. Thus you could get a result that isn't evenly
> divisible by your storage unit (usually 8).
>
> Personally, I prefer to just adjust for that, rather than worry about it.
>
> (Typename'size + System.Storage_Unit - 1) / System.Storage_Unit
>

Well, would you worry about it with a type like this:

type Bubba_Type is record
    C : Character; -- one byte
    I   : Integer; -- 4 bytes
end record;

Bubba : Bubba_Type;

Suppose that Integers must align on 4-byte boundaries.  Then you might get:

Bubba_Type'Size = 40 (= 5 bytes)

(Typename'size + System.Storage_Unit - 1) / System.Storage_Unit
= ( 40 + 8 - 1)/8 = 47/8 = 6 (bytes)

But actually:

Bubba'Size = 64 (= 8 bytes)

GNAT provides a nice attribute 'Object_Size that can be used on the type to
give you what the size of an object of that type would be.

Markku Kotiaho