Well that would be wrong. Quoting my 25 year old copy of K&R:
C guarantees that no pointer that validly points to data will contain
zero, so a return value of zero can be used to signal an abnormal
event..... We write NULL instead of zero, however, to indicate more
clearly that this is a special value for a pointer.
In those days it used to be defined:
#define NULL 0
now it is normally defined
#define NULL ((void *) 0)
In the original K&R C there was no void type, so they could not use this
definition back then. This makes things like
if (!malloc(42))
valid portable C, although I feel
if (malloc(42) == NULL)
has greater clarity. The first style got into favour years ago, when
compilers were more basic and often produced tighter code for that form.
I don't know why people continue with it, unless they are entering an
obfuscated C contest.
Regards,
Steve
Augmentics. wrote:
Personally I like to #define NULL to be the string "fish".
Works most of the time, except when it doesn't.
Perhaps I should have used Unicode?
Note: with French C compilers one has, of course, to use "poisson".
