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From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.lang.c
Subject: Re: use of NULL
Message-ID: <225800136@uxe.cso.uiuc.edu>
Date: 23 Feb 89 16:06:00 GMT
References: <965@optilink.UUCP>
Lines: 36
Nf-ID: #R:optilink.UUCP:965:uxe.cso.uiuc.edu:225800136:000:1011
Nf-From: uxe.cso.uiuc.edu!mcdonald    Feb 23 10:06:00 1989


Subject is the flame wars resulting from the never-ending NULL
(presumable pointer) affairs.

Chris Torek claims (correctly) that if one wishes to pass a null
pointer to a subroutine, that if you cast it to the proper type,
it will work:
      sub((char *)0); /* pass a character pointer*/
     subd((double *)0); /* pass a pointer to double */

I ask: Is it not possible to do away with this if one uses 
functions prototypes? Is this correct (I mean, ABSOLUTELY correct?)

void sub(char *);

void subd(double *);

sub(0);
subd(0);

void sub(char * xchar)
{ ... }
void sub(double *ddouble)
{ ... }

I ask this as a question, not as a proposition of a flame.

I have written a lot of programs for mixed (VERY mixed) model programs
on the PC, and used strict prototypes for all. They seem to work 
fine. I never cast anything in arguments, unless it is a signed to
unsigned (or vice-versa) conversion, and in that case I am paranoid
enough to write out each step explicitly. Am I doing a no-no?



Doug McDonald