[GRASS-dev] Re: [GRASS-SVN] r33717 - grass/trunk/lib/gis

[Glynn Clements]

Markus Neteler wrote:

> > Author: glynn
> > Date: 2008-10-07 06:01:59 -0400 (Tue, 07 Oct 2008)
> > New Revision: 33717
> >
> > Modified:
> >   grass/trunk/lib/gis/null_val.c
> > Log:
> > Make G_is_[fd]_null_value() check for any NaN, not just all-ones
> 
> 
> /me backport this?

Maybe.

Unless there are modules which genuinely need to distinguish GRASS
nulls from other NaNs, the only real risk is a broken compiler
"optimising" the "x != x" test away.

At one time, that was quite likely, but compilers tend to be better
nowadays (i.e. gcc has effectively destroyed the market for half-baked
C compilers).

Although it's a very small risk, if it does break, it's rather
significant.

-- 
Glynn Clements <glynn at gclements.plus.com>