Re: C's sizeof

[Simon Wright <simon@pushface.org>]

Adam Beneschan <adam@irvine.com> writes:

> On Thursday, April 12, 2012 9:27:09 AM UTC-7, Simon Wright wrote:
>> The (draft) ARM Annex B.3[1] says at para 73 - Note 7 -
>> 
>>     "To obtain the effect of C's sizeof(item_type), where Item_Type is
>>     the corresponding Ada type, evaluate the expression:
>>     size_t(Item_Type'Size/CHAR_BIT)."
>> 
>> Should that not be
>> 
>>     size_t((Item_Type'Size + CHAR_BIT - 1)/CHAR_BIT)
>> 
>> ?
>> 
>> [1] http://www.ada-auth.org/standards/12rm/html/RM-B-3.html
>
> Does C even support types whose sizes aren't a multiple of a byte?  If
> it doesn't, then since B.3 is talking about the Ada type
> "corresponding" to a C type, the question is probably moot.

Doesn't B.3 apply to types with Convention => C?

GNAT allows

   type N2 is range 0 .. Integer'Last - 1;
   pragma Convention (C, N2);

and N2'Size is 31 ...