Re: [PATCH] pid: change task_struct::pid to read-only

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.

Oleg.