warning: left shift count >= width of type (i386)

[Ricardo Jose Maraschini]

* Ricardo Jose Maraschini (ricardo.maraschini at opservices.com.br) 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 << 32) | tv->tv_usec;
+	return ((pqueue_pri_t)tv->tv_sec << 32) | tv->tv_usec;
 }
 
 static int sq_cmp_pri(pqueue_pri_t next, pqueue_pri_t cur)

------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/