On 13/12/22, Oleg Nesterov wrote:
> On 12/20, Peter Zijlstra wrote:
> >
> > On Fri, Dec 20, 2013 at 08:01:57PM +0100, Oleg Nesterov wrote:
> > > The only problem is that
> > >
> > > #define ASSIGN_CONST(l, r) (*(typeof(r) *)&(l) = (r))
> > >
> > > obviously can't work in this case ;) We need something more clever.
> >
> > Hmm indeed, C++ has both the const_cast<>() thingy and the template
> > system is powerful enough to actually implement const_cast<>() inside
> > the language.
>
> So, how about
>
> #define CONST_CAST(type, lval) \
> (*({ \
> (void)((type *)0 == &(lval)); \
> (type *)&(lval); \
> })) \
>
> de_thread/copy_process can do
>
> CONST_CAST(pid_t, tsk->pid) = leader->pid;
>
> and if "type" is wrong we have a warning.
Cool. This works very nicely. Thanks for the ideas Oleg!
> Oleg.
- RGB
--
Richard Guy Briggs <rbri...@redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red
Hat
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