+++ /dev/null
-.\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
-.\" Fri Apr 2 11:32:09 MET DST 1993
-.\"
-.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
-.\" 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, see
-.\" <http://www.gnu.org/licenses/>.
-.\" %%%LICENSE_END
-.\"
-.\" 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>
-.\"
-.\" 2007-10-23 mtk: created as a new page, by taking the content
-.\" specific to the _syscall() macros from intro(2).
-.\"
-.TH _SYSCALL 2 2007-12-19 "Linux" "Linux Programmer's Manual"
-.SH NAME
-_syscall \- invoking a system call without library support (OBSOLETE)
-.SH SYNOPSIS
-.B #include <linux/unistd.h>
-
-A _syscall macro
-
-desired system call
-.SH DESCRIPTION
-The important thing to know about a system call is its prototype.
-You need to know how many arguments, their types,
-and the function return type.
-There are seven macros that make the actual call into the system easier.
-They have the form:
-.sp
-.RS
-.RI _syscall X ( type , name , type1 , arg1 , type2 , arg2 ,...)
-.RE
-.PP
-where
-.IP
-.I X
-is 0\(en6, which are the number of arguments taken by the
-system call
-.IP
-.I type
-is the return type of the system call
-.IP
-.I name
-is the name of the system call
-.IP
-.I typeN
-is the Nth argument's type
-.IP
-.I argN
-is the name of the Nth argument
-.PP
-These macros create a function called
-.I name
-with the arguments you
-specify.
-Once you include the _syscall() in your source file,
-you call the system call by
-.IR name .
-.SH FILES
-.I /usr/include/linux/unistd.h
-.SH CONFORMING TO
-The use of these macros is Linux-specific, and deprecated.
-.SH NOTES
-Starting around kernel 2.6.18, the _syscall macros were removed
-from header files supplied to user space.
-Use
-.BR syscall (2)
-instead.
-(Some architectures, notably ia64, never provided the _syscall macros;
-on those architectures,
-.BR syscall (2)
-was always required.)
-
-The _syscall() macros
-.I "do not"
-produce a prototype.
-You may have to
-create one, especially for C++ users.
-
-System calls are not required to return only positive or negative error
-codes.
-You need to read the source to be sure how it will return errors.
-Usually, it is the negative of a standard error code,
-for example,
-.RI \- EPERM .
-The _syscall() macros will return the result
-.I r
-of the system call
-when
-.I r
-is nonnegative, but will return \-1 and set the variable
-.I errno
-to
-.RI \- r
-when
-.I r
-is negative.
-For the error codes, see
-.BR errno (3).
-
-When defining a system call, the argument types
-.I must
-be
-passed by-value or by-pointer (for aggregates like structs).
-.\" The preferred way to invoke system calls that glibc does not know
-.\" about yet is via
-.\" .BR syscall (2).
-.\" However, this mechanism can be used only if using a libc
-.\" (such as glibc) that supports
-.\" .BR syscall (2),
-.\" and if the
-.\" .I <sys/syscall.h>
-.\" header file contains the required SYS_foo definition.
-.\" Otherwise, the use of a _syscall macro is required.
-.\"
-.SH EXAMPLE
-.nf
-#include <stdio.h>
-#include <stdlib.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);
-
-/* Note: if you copy directly from the nroff source, remember to
-REMOVE the extra backslashes in the printf statement. */
-
-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);
- exit(EXIT_SUCCESS);
-}
-.fi
-.SS Sample output
-.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 SEE ALSO
-.BR intro (2),
-.BR syscall (2),
-.BR errno (3)
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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