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.TH stddef.h 3HEAD "10 Sep 2004" "SunOS 5.11" "Headers"
.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
.mk
.na
\fB\fBNULL\fR\fR
.ad
.sp .6
.RS 4n
Null pointer constant.
.RE

.sp
.ne 2
.mk
.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
.mk
.na
\fB\fBptrdiff_t\fR\fR
.ad
.RS 13n
.rt  
Signed integer type of the result of subtracting two pointers.
.RE

.sp
.ne 2
.mk
.na
\fB\fBwchar_t\fR\fR
.ad
.RS 13n
.rt  
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
.mk
.na
\fB\fBsize_t\fR\fR
.ad
.RS 13n
.rt  
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
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityStandard
.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)