🚀 go-pugleaf

In article <4ian7m$h54@solutions.solon.com> runner!amileto@uunet.uu.net (Angelo John Mileto) writes:
>In article <4i97jv$8hn@solutions.solon.com> ANH@KUHUB.CC.UKANS.EDU writes:
>>But here is one simple rule,  always use (Type*)0 and not null for null 
>>pointer check.  Show my a thousand standards that say I don't need 
>>to do that, I would still use the construct.
>>
>>Anh
>
>I'll byte, what exactly does (Type*)0 do that NULL doesn't do and why will
>it always work whereas NULL may or may not?
>
Consider a machine where a (char *) and an (int *) are not the same
(Honeywell DPS/6 for example), and a function written with the old K&R
style.  Then you always needed to cast your NULL pointers to get them
into the right size/format for the called function.  I used to keep
arround a macro for just this

#define Nullp(type) ((type *)NULL)

All this changed with ANSI C and prototypes.  By using protypes
instead I can just code NULL, and the explicit cast is no longer
needed.  I find it a better technique.  I no longer routinely liter
code with casts.  This reduces clutter in the code and make the
remaining casts stand out as something special.


Summary.  Prior to ANSI C and prototypes, coding (type *)0 was
a useful practice.  It has been superceded by changes in the language
and is no longer particularly good style.

[Except, of course, in variadic function argument lists. -mod]