STDDEF(3) BSD Library Functions Manual STDDEF(3)NAMEstddef — standard type definitions
SYNOPSIS
#include <stddef.h>
DESCRIPTION
The <stddef.h> header defines the following types and macros:
1. ptrdiff_t, a signed integer type of the result of subtracting
two pointers;
2. size_t, an unsigned integer type of the result of the sizeof()
operator;
3. wchar_t, an integer type whose range of values can represent
distinct wide-character codes for all members of the largest
character set specified among the supported locales: the null
character has the code value 0 and each member of the character
set has a code value equal to its value when used as the lone
character in an integer character constant;
4. NULL, which expands to an implementation-defined null pointer
constant; and
5. offsetof(), a macro that expands to an integer constant as
described in offsetof(3).
Some of the described types and macros may appear also in other headers.
SEE ALSOoffsetof(3), stdlib(3), unistd(3)STANDARDS
As described here, the <stddef.h> header conforms to ISO/IEC 9899:1999
(“ISO C99”) and IEEE Std 1003.1-2001 (“POSIX.1”). Some of the types and
macros conform to earlier standards such as ANSI X3.159-1989
(“ANSI C89”).
HISTORY
In the current form the <stddef.h> header was introduced in NetBSD 0.8,
the first official release of NetBSD. Some definitions such as NULL were
first introduced already in the <nsys/param.h> header of Version 4 AT&T
UNIX.
BSD April 10, 2011 BSD
