stddef.h Header File stddef.h
Header for standard definitions
#include <stddef.h>
stddef.h defines three types and two macros that are used through
the library. They are as follows:
NULL Null pointer
offsetof()Offset of a field within a structure
ptrdiff_tNumeric difference between two pointers
size_t Type returned by sizeof operator
wchar_t Typedef for wide chars
***** See Also *****
header files
COHERENT Lexicon Page 1