.\"
.\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
.\"   Fri Apr  2 11:32:09 MET DST 1993
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
.\" USA.
.\"
.\" Tue Jul  6 12:42:46 MDT 1993 <dminer@nyx.cs.du.edu>
.\" Added "Calling Directly" and supporting paragraphs
.\"
.\" Modified Sat Jul 24 15:19:12 1993 by Rik Faith <faith@cs.unc.edu>
.\"
.\" Modified 21 Aug 1994 by Michael Chastain <mec@shell.portal.com>:
.\"   Added explanation of arg stacking when 6 or more args.
.\"
.\" Modified 10 June 1995 by Andries Brouwer <aeb@cwi.nl>
.\"
.\" Japanese Version Copyright (c) 1997 KUNIMOTO Yasuhiro, all rights reserved.
.\" Translated 1997-06-27, KUNIMOTO Yasuhiro (hiro@kthree.co.jp)
.\" Modified 1997-07-05, Yoshiki Sugiura (yox@in.aix.or.jp)
.\" Modified 1997-07-06, Yoshiki Sugiura (yox@in.aix.or.jp)
.\" Modified 1999-03-21, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2000-01-03, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2004-05-23, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2005-02-21, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\"
.\"WORD:	system call	ƥࡦ
.\"
.TH INTRO 2 1996-05-22 "Linux 1.2.13" "Linux Programmer's Manual"
.SH ̾
intro, _syscall \- ƥࡦ
.SH 
ξϤ Linux Υƥࡦ򵭽ҤƤ롣
Linux 2.0 Ǥ 164 ĤΥƥࡦ뤬¸ߤ롣
syscall(2) 򻲾ȤΤȡ
.SS "ľܸƤӽФ"
ۤȤɤξ硢ľܥƥࡦƤӽФɬפϤʤ
ˤäƤɸ C 饤֥ŬڤʴؿƤʤȤ⤢롣
.SS ""
.B #include <linux/unistd.h>

A _syscall macro

desired system call

.SS 
ƥࡦ˴ؤƤΥץȥפΤ뤳Ȥפ
롣θĿη֤ͤηΤʤФʤʤ
ºݤλѤˤäƤϡưפ˥ƥƤӽФ˼ 6 Ĥ
ޥѰդƤ롣ηϰʲ̤Ǥ:
.sp
.RS
.RI _syscall X ( type , name , type1 , arg1 , type2 , arg2 ,...)
.RS
.HP
\fIX\fP  0\(en5 ͤǡƥࡦ뤬ɬפȤοǤ롣
.HP
\fItype\fP ϥƥࡦ֤ͤηǤ롣
.HP
\fIname\fP ϥƥࡦ̾Ǥ롣
.HP
\fItypeN\fP  N ܤΰηǤ롣
.HP
\fIargN\fP  N ܤΰ̾Ǥ롣
.RE
.RE
.sp
Υޥϡꤷ \fIname\fP Ȥ̾δؿ롣
٥եǤ _syscall() ޥƤǤȡ
\fIname\fP ǤΥƥࡦƤ֤ȤǤ롣
.SH 
.nf
.sp
#include <stdio.h>
#include <errno.h>
#include <linux/unistd.h>	/* for _syscallX macros/related stuff */
#include <linux/kernel.h>	/* for struct sysinfo */

_syscall1(int, sysinfo, struct sysinfo *, info);

/* ա nroff Υե뤫ľܥԡȤ 
printf ʸ˴ޤޤƤ;ʬʥХåå
Ȥ˺ʤ褦 */

int main(void)
{
	struct sysinfo s_info;
	int error;

	error = sysinfo(&s_info);
	printf("code error = %d\\n", error);
        printf("Uptime = %lds\\nLoad: 1 min %lu / 5 min %lu / 15 min %lu\\n"
                "RAM: total %lu / free %lu / shared %lu\\n"
                "Memory in buffers = %lu\\nSwap: total %lu / free %lu\\n"
                "Number of processes = %d\\n",
		s_info.uptime, s_info.loads[0],
		s_info.loads[1], s_info.loads[2],
		s_info.totalram, s_info.freeram,
		s_info.sharedram, s_info.bufferram,
		s_info.totalswap, s_info.freeswap,
		s_info.procs);
	return(0);
}
.fi
.SH 
.nf
code error = 0
uptime = 502034s
Load: 1 min 13376 / 5 min 5504 / 15 min 1152
RAM: total 15343616 / free 827392 / shared 8237056
Memory in buffers = 5066752
Swap: total 27881472 / free 24698880
Number of processes = 40
.fi
.SH 
_syscall() ޥϥץȥפʤ桼ϼʬ
ץȥפ񤫤ʤФʤʤ⤷ʤ 
C++ 桼ξä˽פǤ롣
.sp
ƥࡦΥ顼ɤΤߤޤΥ顼ɤΤߤ
֤ȤƤ櫓ǤϤʤ
Υƥࡦ뤬ɤΤ褦ʥ顼ɤ֤ˤĤƳǧ
ˤϤΥɤɤɬפ롣
Ƥξ硢ɸΥ顼ɤ (㤨 \-\fBEPERM\fP Τ褦)
֤
_syscall() ޥϡΥƥࡦ֤ \fIr\fP Ǥʤ硢
ͤ򤽤Τޤ֤ξˤѿ
.I errno
 \-\fIr\fP ꤷ \-1 ֤
ƥ顼ɤ˴ؤƤ
.BR errno (3)
򻲾ȡ
.sp
.RB ( mmap
ʤɤ) ĤΥƥࡦ 5Ĥ¿ΰ׵᤹롣
äƥࡦϥå˰ץå夷
ΰΤޤؤΥݥ󥿤Ϥƽ롣
.sp
ƥࡦ硢ΰηϤ (by-value) 
(¤ΤΤ褦ʽŪʥǡξ) ݥϤ(by-pointer)
ǤʤФʤʤ
.sp
glibc ޤΤʤƥࡦưΤ˹ޤˡ
.BR syscall (2)
ȤȤǤ롣
.SH 
ξϤǤϡʲ˼ά Unix μ̤ɸɽ˻Ѥ롣
.TP
SVr4
System V Release 4 Unix
"Programmer's Reference Manual: Operating System API (Intel processors)"
(Prentice-Hall1992, ISBN 0-13-951294-2) 
ܤƤ롣
.TP
SVID
System V Interface Definition
"The System V Interface Definition, Fourth Edition" 
ܤƤ롣
.TP
POSIX.1
IEEE 1003.1-1990 part 1̾Ǥ ISO/IEC 9945-1:1990s 
"IEEE Portable Operating System Interface for Computing Environments"
Ȥ⤤롣 Donald Lewine  "POSIX Programmer's Guide"
(O'Reilly & Associates,Inc., 1991, ISBN 0-937175-73-0) ˤ⤬롣
.TP
POSIX.1b
ܿǽʥڥ졼ƥ󥰥ƥΤΥꥢ륿ൡˤĤ
ܤƤ IEEE Std 1003.1b-1993 (POSIX.1b standard)
̾ ISO/IEC 9945-1:1996
Bill O. Gallmeister 
"Programming for the real world \- POSIX.4"
(O'Reilly & Associates, Inc. ISBN1-56592-074-0)
ˤ⤬롣
.TP
SUS, SUSv2
Single Unix Specification.
(X/Open  The Open Group ˤäƺ줿
http://www.UNIX-systems.org/version2/ ⻲ȤΤȡ)
.TP
4.3BSD/4.4BSD
Berkeley Unix 4.3  4.4 ǥȥӥ塼
4.4BSD  4.3 Фƾ̸ߴǤ롣
.TP
V7
٥븦ͳ褹븵 UnixǤ Version 7
.SH ե
.I /usr/include/linux/unistd.h
.SH Ϣ
.BR syscall (2),
.BR errno (3)