sizeof in ADA

sizeof in ADA

[sisi.ard]

I would like to know how to write an equivolent of the C function
"sizeof "
in Win32ADA to use with the GDI function " getobject " like this :

Buffer_Size:=Getobject(Mon_Bitmap,
         Sizeof(Bitmap), -- this line obviously don't works
         Buffer);

Re: sizeof in ADA

[Lutz Donnerhacke]

* sisi.ard@laposte.net wrote:
> I would like to know how to write an equivolent of the C function "sizeof
> " in Win32ADA to use with the GDI function " getobject " like this :

'Size_in_Storage_Elements

Re: sizeof in ADA

[Marc A. Criley]

Lutz Donnerhacke wrote:
> 
> 'Size_in_Storage_Elements

Did you mean 'Max_Size_In_Storage_Elements?

There's no Size_In_Storage_Elements attribute listed in either the RM or 
amongst GNAT's implementation defined attributes.

-- Marc A. Criley
-- www.mckae.com
-- DTraq - XPath In Ada - XML EZ Out

Re: sizeof in ADA

[Lutz Donnerhacke]

* Marc A. Criley wrote:
> Lutz Donnerhacke wrote:
>> 'Size_in_Storage_Elements
>
> Did you mean 'Max_Size_In_Storage_Elements?

Yes.

Re: sizeof in ADA

[Georg Bauhaus]

sisi.ard@laposte.net wrote:
> I would like to know how to write an equivolent of the C function
> "sizeof "
> in Win32ADA to use with the GDI function " getobject " like this :
> 
> Buffer_Size:=Getobject(Mon_Bitmap,
>          Sizeof(Bitmap), -- this line obviously don't works
>          Buffer);


What is the Ada type of Bitmap?

from GetObject:

hObject   ...
nCount    int  Secifies the number of bytes to be copied
                to the buffer
lpObject  ...

What do you want to copy?
The bitmap related structures in the Window API provide
information to compute the size of the bitmap in bytes
IIRC.

Re: sizeof in ADA

[cdm]

Ada 83 says X'SIZE returns the number of bits allocated to hold the
object.

sisi.ard@laposte.net wrote:

> I would like to know how to write an equivolent of the C function
> "sizeof "
> in Win32ADA to use with the GDI function " getobject " like this :
>
> Buffer_Size:=Getobject(Mon_Bitmap,
>          Sizeof(Bitmap), -- this line obviously don't works
>          Buffer);

Re: sizeof in ADA

[Jeffrey Carter]

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

Re: sizeof in ADA

[Martin Krischik]

sisi.ard@laposte.net wrote:

> I would like to know how to write an equivolent of the C function
> "sizeof "
> in Win32ADA to use with the GDI function " getobject " like this :
> 
> Buffer_Size:=Getobject(Mon_Bitmap,
>          Sizeof(Bitmap), -- this line obviously don't works
>          Buffer);

See:

http://en.wikibooks.org/wiki/Programming:Ada:Attributes:'Size


Martin

-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com