NULL -- Manifest Constant

The manifest  constant NULL is defined  in the header file  stddef.h. It is
the  null  pointer (char  *)0,  which  is a  pointer  initialized to  zero.
Numerous routines return this value to  indicate failure; it is useful as a
return value  because it points nowhere, and so  removes the possibility of
accidentally destroying a section of memory after failure.

See Also

manifest constant,
NUL,
pointer,
stdio.h
ANSI Standard, §7.1.6

© 2012 by Stephen A. Ness