cvs commit: src/sys/kern subr_bus.c

[Julian Elischer]

On Wed, 24 Mar 2004, David Schultz wrote:

> On Mon, Mar 22, 2004, David O'Brien wrote:
> > On Mon, Mar 22, 2004 at 06:06:48PM -0800, Nate Lawson wrote:
> > > > +			if (bootverbose && flags & INTR_MPSAFE)
> > .. 
> > > I recommend you parenthesize (flags & INTR_MPSAFE).
> > 
> > man operator  :-)
> 
> For some reason, gcc complains about the lack of excessive
> parentheses for expressions like 'a && b || c' and
> 'foo >> shift1 + shift2', but not for 'a && b & c'.
> It's too bad there's no documentation on which parts of
> operator(7) are supposed to be considered obvious (along
> with a note that =='s priority over & is a mistake---that
> one often bites me.)
> 

I agree. it is often late at night when staring at code looking for a
bug that one fails to notice the subtlties of operator precedence.

One person's "obvious" is not always obvious to others. Especially if
one has noticed differences in precedence between different languages
one has worked with in one's life.

a couple of extra parens on a statement with 'non-normal' form
such as that above can save hours later.

julian