On 20 July 2010 01:02, Dave Airlie <airl...@gmail.com> wrote: > Its abuse because if you read that your brain would have to go wtf at > least twice, > > I don't mind !!, since your brain can deal with that, but using binary > operators where you really want logical is really bad for the reader. > > Open source code should be optimised for readers not writers. > Sure, I actually agree with following whatever style / conventions a specific project prefers, no argument there. I've sent an updated patch.
OT at this point, I'd like to explain my point of view though: - != isn't equivalent to "logical xor". Logical xor would evaluate to 0 for "a xor b" for any non-zero a and b. != clearly doesn't do that, except for the cases where it's equivalent to ^. - != isn't a logical operator at all, it's a relational operator. - The main, significant, difference between logical operators and their bitwise equivalents is short-circuit behaviour. Otherwise e.g. "a && b" is equivalent to "!!a & !!b". Since short-circuit doesn't make sense for xor, it's perhaps not surprising that C doesn't have a concept of "logical xor", it would be redundant. So since the meaning of that line is "either one or the other", I figured a xor expressed that more clearly than an equality operator. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
