'\" te
.\" Copyright (c) 2001, The IEEE and The Open Group. All Rights Reserved. Portions Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved.
.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
.\" http://www.opengroup.org/bookstore/.
.\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.
.\"  This notice shall appear on any product containing this material.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH STDDEF.H 3HEAD "Sep 10, 2004"
.SH NAME
stddef.h, stddef \- standard type definitions
.SH SYNOPSIS
.LP
.nf
#include <\fBstddef.h\fR>
.fi

.SH DESCRIPTION
.sp
.LP
The <\fBstddef.h\fR> header defines the following macros:
.sp
.ne 2
.na
\fB\fBNULL\fR\fR
.ad
.sp .6
.RS 4n
Null pointer constant.
.RE

.sp
.ne 2
.na
\fB\fBoffsetof(type, member-designator)\fR\fR
.ad
.sp .6
.RS 4n
Integer constant expression of type \fBsize_t\fR, the value of which is the
offset in bytes to the structure member (\fBmember-designator\fR), from the
beginning of its structure (\fBtype\fR).
.RE

.sp
.LP
The <\fBstddef.h\fR> header defines the following types:
.sp
.ne 2
.na
\fB\fBptrdiff_t\fR\fR
.ad
.RS 13n
Signed integer type of the result of subtracting two pointers.
.RE

.sp
.ne 2
.na
\fB\fBwchar_t\fR\fR
.ad
.RS 13n
Integer type whose range of values can represent distinct wide-character codes
for all members of the largest character set specified among the locales
supported by the compilation environment: the null character has the code value
0 and each member of the portable character set has a code value equal to its
value when used as the lone character in an integer character constant.
.RE

.sp
.ne 2
.na
\fB\fBsize_t\fR\fR
.ad
.RS 13n
Unsigned integer type of the result of the \fBsizeof\fR operator.
.RE

.sp
.LP
The implementation supports one or more programming environments in which the
widths of \fBptrdiff_t\fR, \fBsize_t\fR, and \fBwchar_t\fR are no greater than
the width of type \fBlong\fR. The names of these programming environments can
be obtained using the \fBconfstr\fR(3C) function or the \fBgetconf\fR(1)
utility.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
.TE

.SH SEE ALSO
.sp
.LP
\fBgetconf\fR(1), \fBconfstr\fR(3C), \fBtypes.h\fR(3HEAD),
\fBwchar.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)