Subject: Re: top
To: Colin Wood <cwood@ichips.intel.com>
From: D'Arcy J.M. Cain <darcy@druid.net>
List: current-users
Date: 07/16/1998 12:24:45
Thus spake Colin Wood
> > This brings up another question for me.  I have been asking about kernel
> > panics and I may have found the problem.  It appears that defining those
> > constants to anything is enough to trigger the code but perhaps it is
> > not consistent.  I had UVM in the kernel that was causing all the panics
> > so I removed it and changed the "yes" to a "no" in the mk.conf file.  It
> > looks like that caused the UVM code to be triggered just as if I had said
> > "yse."  Perhaps your problem is that sometime it needs "yes" and sometimes
> > it needs anything so your "1" is ambiguous.
> > 
> > I'm just guessing here.  Anyone more familiar with it know for sure?
> 
> The problem is most likely that some code simply does:
> 
> #ifdef UVM
> 
> whilst other code may do:
> 
> #if UVM

Not likely.  It works if UVM is set yo "yes" so I imagine it to be
more like the difference between

#ifdef UVM
  and
#if UVM == yes

Hmm.  I just double checked the syntax with K&R2 and although the latter
is correct according to them, a small test program seems to make that
statement true no matter what the value of UVM or even if it is defined
or not.  I must be missing something.

-- 
D'Arcy J.M. Cain <darcy@{druid|vex}.net>   |  Democracy is three wolves
http://www.druid.net/darcy/                |  and a sheep voting on
+1 416 424 2871     (DoD#0082)    (eNTP)   |  what's for dinner.