Messages in this thread | | | Date | Tue, 5 Oct 2021 20:28:54 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: [RFC][PATCH] rcu: Use typeof(p) instead of typeof(*p) * |
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On Tuesday 2021-10-05 20:06, Mathieu Desnoyers wrote: >> instead of just "typeof(p)", to force the decay to a pointer. > >If the type of @p is an integer, (p) + 0 is still valid, so it will not >prevent users from passing an integer type as argument, which is what >the current implementation prevents. > >Also, AFAIU, the compiler wants to know the sizeof(p) in order to evaluate >(p + 0). Steven's goal is to hide the structure declaration, so that would >not work either.
>>>> typeof(*p) *________p1 = (typeof(*p) *__force)READ_ONCE(p);
#define static_cast(type, expr) ((struct { type x; }){(expr)}.x) typeof(p) p1 = (typeof(p) __force)static_cast(void *, READ_ONCE(p));
Let the name not fool you; it's absolutely _not_ the same as C++'s static_cast, but still: it does emit a warning when you do pass an integer, which is better than no warning at all in that case.
*flies away*
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