On Tuesday 2015-04-07 19:45, Alexander Duyck wrote:
>>>> -#define prefetch(x) 1
>>>> +#define prefetch(x) ((void)0)
>>>>
>>> Why not just use "do {} while (0)"? I know that is what is used in the
>>> kernel for functions that don't do anything.
>> I may be getting the terms wrong, but:
>> do{}while(0) is not an expression, it is a (block) control statement.
>> In particular, do{}while(0) won't evaluate to an rvalue.
>
> Right. That is the point in this case. I am assuming what Arturo is trying to
> accomplish since you shouldn't be able to evaluate ((void)0) as an rvalue
> either.
The difference is that
int i;
i = 1, (void)0;
compiles, while
i = 1, do{}while(0);
will not. Even less so with
int i = 1, (void)0 vs
int i = 1, do{}while(0);
[that looks so obscure that even I need to go figure out why that is
even permitted at this point].
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