Nagios Support Forum

On 09/04/2012 09:15 AM, Andreas Ericsson wrote:
> On 09/03/2012 10:23 PM, Ricardo Jose Maraschini wrote:
>> * Ricardo Jose Maraschini ([email protected]) wrote:
>>> OK, I'm not pretty sure about following, but here we go.
>>> I tried to compile current nagios on a i386 arch and received the
>>> following warning:
>>>
>>> squeue.c:34: warning: left shift count >= width of type
>>>
>>> If i'm right, long is four bytes long on i386 arch, and as tv_sec is
>>> a long(accordingly to gettimeofday(2)) the result of line 34 on squeue.c
>>> is unpredictable.
>>>
>>> Am I right or I'm missing something?
>>>
>>> Compiling on a sparc64 and in a x86_64 environment i haven't received
>>> the same warning. On these architectures, sizeof(long) shows me 8 bytes.
>>>
>>> What are the performance implications of my patch below?
>>>
>>> -rm
>>
>> The patch below seems to be much more appropriate than the previous one.
>>
>> ===================================================================
>> --- lib/squeue.c (revision 2138)
>> +++ lib/squeue.c (working copy)
>> @@ -31,7 +31,7 @@
>>
>> static pqueue_pri_t evt_compute_pri(struct timeval *tv)
>> {
>> - return (tv->tv_sec tv_usec;
>> + return ((pqueue_pri_t)tv->tv_sec tv_usec;
>> }
>>
>
> That's odd. Casting to pqueue_pri_t shouldn't be necessary when the
> function return pqueue_pri_t. I worry a bit that this might break
> on systems with less-than-totally-sane compiler, where the value
> will first be calculated as a normal word and then the result cast
> explicitly to a longword. I've done a different change:
>
> pqueue_pri_t ret;
> ret = tv->tv_sec;
> ret ret |= tv->tv_usec;
> return ret;
>
> which should keep even the most retarded compiler from doing anything
> wrong.
>
> Many thanks for the bugreport and the patch though
>

And now it's pushed, so feel free to check out the latest and greatest
version from svn or git and give it a whirl.

--
Andreas Ericsson [email protected]
OP5 AB www.op5.se
Tel: +46 8-230225 Fax: +46 8-230231

Considering the successes of the wars on alcohol, poverty, drugs and
terror, I think we should give some serious thought to declaring war
on peace.





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