Re: CVS commit: src/sys/lib/libkern

[christos%astron.com@localhost (Christos Zoulas)]

In article <20060328061040.GU29748%snowdrop.l8s.co.uk@localhost>,
David Laight  <david%l8s.co.uk@localhost> wrote:
>On Mon, Mar 27, 2006 at 09:18:33PM +0000, David Young wrote:
>> 
>> Module Name: src
>> Committed By:        dyoung
>> Date:                Mon Mar 27 21:18:33 UTC 2006
>> 
>> Modified Files:
>>      src/sys/lib/libkern: libkern.h
>> 
>> Log Message:
>> Per discussion on source-changes@, add __arraycount(array) for
>> counting the number of elements in a static array, using the idiom,
>> sizeof(array)/sizeof(array[0]).
>
>How about casting the result to 'int' ?
>The domain of the result will always fit in an int, whereas sizeof
>will return a 64bit type on LP64 systems.
>Using 'int' (not 'unsigned int') allows:
>       int i;
>       ...
>       for (i = 0; i < __arraycount(xxx); i++)
>               ...
>work (without giving a 'signed v unsigned comparison' warning).
>

This is wrong given that the number is unsigned. Although it fits in
an int, it does not make it signed. You should be converting your
loops to use u_int or size_t instead.

christos