Re: sizeof in ADA

[Jeffrey Carter <spam@spam.com>]

sisi.ard@laposte.net wrote:
> I would like to know how to write an equivolent of the C function
> "sizeof "

There is the 'Max_Size_In_Storage_Units attribute, which may be what you 
want.

The 'Size attribute gives the size in bits of a subtype or object. For a 
stand-alone object, 'Size is usually a multiple of System.Storage_Unit, 
which is the number of bits in a storage unit (8 on a byte-oriented 
processor).

Note that 'Size can differ between a subtype and an object. For many 
platforms and compilers:

Boolean'Size = 1
Natural'Size = 31

B : Boolean;
N : Natural;

B'Size = 8;
N'Size = 32

So Object'Size / System.Storage_Unit will give you the correct value for 
an object. It may be better to base your values on the object than on 
the subtype.

Another way is to instantiate Ada.Storage_IO for the subtype. This then 
gives you the constant Buffer_Size, which is what you want. This is 
rather a heavyweight solution, however.

-- 
Jeffrey Carter
"Now go away or I shall taunt you a second time."
Monty Python and the Holy Grail
E-mail: jeffrey_r_carter-nr [commercial-at]
         raytheon [period | full stop] com