Tejun Heo wrote:
>> +#define hash_min(val, bits) \
>> +({ \
>> + sizeof(val) <= 4 ? \
>> + hash_32(val, bits) : \
>> + hash_long(val, bits); \
>> +})
> Also, you probably want () around at least @val. In general,
> it's a good idea to add () around any macro argument to avoid nasty
> surprises.
Er... not in this case, you don't. If a macro argument is passed verbatim
as an argument to a function, it doesn't need additional parens.
That's because the one guarantee you have about a macro argument is
that it can't contain any (unquoted) commas, and there's nothing lower
precedence than the comma. So it's safe to delimit a macro argument
with *either* parens *or* a comma.
So you can go ahead and write:
#define hash_min(val, bits) \
(sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
... which is easier to read, anyway.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
