Re: [PATCH] typeof: Remove type qualifiers for atomic types

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Wed, 25 Jun 2014, Sebastian Huber wrote:

> On 06/25/2014 05:56 PM, Joseph S. Myers wrote:
> > On Wed, 25 Jun 2014, Sebastian Huber wrote:
> > 
> > > 2014-06-25  Sebastian Huber  <sebastian.huber@embedded-brains.de>
> > > 
> > > 	* c-parser.c (c_parser_declaration_or_fndef): Discard all type
> > > 	qualifiers in __auto_type for atomic types.
> > > 	(c_parser_typeof_specifier): Discard all type qualifiers in
> > > 	__typeof__ for atomic types.
> > This patch should include a testcase that typeof is discarding volatile
> > (you can e.g. declare an extern variable twice, once as int and once as
> > typeof (*p) where p is volatile _Atomic int *, so the type compatibility
> > check fails unless volatile is discarded).
> > 
> 
> Would be something like this all right for the check?
> 
> #define CHECK_CORRESPONDING(TYPE1, TYPE2) \
> do { TYPE1 a; TYPE2 *b = &a; TYPE2 c; TYPE1 *d = &c; } while (0)
> 
> void f(void)
> {
> const int *ci;
> volatile int *vi;
> CHECK_CORRESPONDING(int *, __typeof__(ci));
> CHECK_CORRESPONDING(int *, __typeof__(vi));
> }

Yes.

> I think its not possible to write a test for the restrict, since it cannot be
> part of a type?

You should be able to use types such as int *_Atomic restrict * (and then 
test that typeof (*p) is int *, if p has that type).

-- 
Joseph S. Myers
joseph@codesourcery.com