references to dereferenced null pointers

[Bob Goudreau]

In article <945 at ns-mx.uiowa.edu>, williams at umaxc.weeg.uiowa.edu (Kent
Williams) writes:
> In article <16179 at haddock.ima.isc.com> karl at haddock.ima.isc.com (Karl
Heuer) writes:
> >In article <1990Mar14.164539.23685 at utzoo.uucp> henry at utzoo.uucp
(Henry Spencer) writes:
> >>There is absolutely nothing wrong with having a pointer representation in
> >>which the bit pattern for a null pointer is not all zeros... except that
> >>there are a lot of old, badly-written programs which will break.  Thus my
> >>earlier comment that it is valid but unwise.
> >
> >Note that "p = 0", "p == 0", "!p", "char *f() { return 0; }" are *not*
> >examples of such badly-written code; they may be bad style, but the compiler
> >is required to generate correct code involving a true null pointer.
> 
> The bottom line in actual practice is that if NULL isn't a binary object 
> of all zero bits, you can get into trouble porting programs.  Using 0 and
> NULL interchangebly is an unfortunate but common practice -- see code
> examples in Stroustroup's C++ book -- many assignments of 0 to
> pointers.

Sigh...

Looks like it's time for Chris Torek to repost his explanation of NULL
and 0....
 
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