Re: [PATCH 6/9] drivers/net/wireless/iwlwifi/iwl-4965.c: Correct use of ! and &

[Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>]

* Bart Van Assche <bart.vanassche-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> If someone writes (!x & !y) instead of (!x && !y) because both x and y 
> have to be evaluated, this means that both x and y have side effects.
> Please keep in mind that the C language does not specify whether x or 
> y has to be evaluated first, so if x and y have to be evaluated in 
> that order, an expression like (!x & !y) can be the cause of very 
> subtle bugs. I prefer readability above brevity.

such expressions _must_ be written as:

  ret1 = x();
  ret2 = y();

  if (ret1 && ret2)
	...

any side-effects are totally un-obvious when they are in expressions and 
someone doing cleanups later on could easily change the '&' to '&&' and 
introduce a bug.

	Ingo
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