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STDDEF(3)                  Library Functions Manual                  STDDEF(3)

NAME
     stddef - 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 ALSO
     offsetof(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.

NetBSD 10.99                    April 10, 2011                    NetBSD 10.99