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.\" Copyright (C) 2006 Justin Pryzby <pryzbyj@justinpryzby.com>
.\" and Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" Permission is hereby granted, free of charge, to any person obtaining
.\" a copy of this software and associated documentation files (the
.\" "Software"), to deal in the Software without restriction, including
.\" without limitation the rights to use, copy, modify, merge, publish,
.\" distribute, sublicense, and/or sell copies of the Software, and to
.\" permit persons to whom the Software is furnished to do so, subject to
.\" the following conditions:
.\"
.\" The above copyright notice and this permission notice shall be
.\" included in all copies or substantial portions of the Software.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
.\" EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
.\" IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
.\" CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
.\" TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
.\" SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
.\"
.\" References:
.\" /usr/lib/gcc/i486-linux-gnu/4.1.1/include/stddef.h
.\" glibc-doc
.\"
.\" Japanese Version Copyright (c) 2006 Akihiro MOTOKI
.\" all rights reserved.
.\" Translated 2006-07-25, Akihiro MOTOKI, Catch up to LDP v2.34
.\"
.TH OFFSETOF 3 2006-05-23 "GNU" "Linux Programmer's Manual"
.SH ̾
offsetof \- ¤ΤΥСΥեåȤ֤
.SH
.nf
.B #include <stddef.h>
.sp
.BI "size_t offsetof(" type ", " member );
.fi
.SH
.BR offsetof ()
ޥϡե \fImember\fP
¤ \fItype\fP ƬΥեåȤ֤
ΥޥͭѤʤΤϡ
¤ΤեɤΥϼˤäѲ뤷
ѥˤեɴ֤ѥǥΥХȿ
㤦ǽ뤫Ǥ롣
η̡륨ȤΥեåȤɬ⤽
ȤΥιפȤϤʤʤ
\fImember\fP Хȶ˰֤Ƥʤ
(ʤӥåȥեɤξ) ˤϡ
ѥǥ顼ȯ롣
.SH ֤
.BR offsetof ()
ϡꤵ줿Ȥλꤵ줿Ǥ
եåȤХñ̤֤
.SH
C89, C99, POSIX.1-2001.
.SH
Linux/i386 ƥǡ
.BR gcc (1)
Υǥեȥץ
ѥ뤵줿硢ΥץϰʲΤ褦ʽϤ֤
.nf
$ ./a.out
offsets: i=0; c=4; d=8 a=16
sizeof(struct s)=16
.fi
.nf
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
int
main(void)
{
struct s {
int i;
char c;
double d;
char a[];
};
/* Ϥϥѥ¸Ǥ */
printf("offsets: i=%ld; c=%ld; d=%ld a=%ld\\n",
(long) offsetof(struct s, i),
(long) offsetof(struct s, c),
(long) offsetof(struct s, d),
(long) offsetof(struct s, a));
printf("sizeof(struct s)=%ld\\n", (long) sizeof(struct s));
exit(EXIT_SUCCESS);
}
.fi
.\" .SH SEE ALSO
.\" FIXME . When one day readdir_r(3) is documented, it should have
.\" a SEE ALSO that refers to this page.
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