[apple/xnu.git] / bsd / man / man2 / syscall.2

.\"	$NetBSD: syscall.2,v 1.4 1995/02/27 12:38:53 cgd Exp $
.\"
.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)syscall.2	8.1 (Berkeley) 6/16/93
.\"
.Dd June 16, 1993
.Dt SYSCALL 2
.Os BSD 4
.Sh NAME
.Nm syscall ,
.Nm __syscall
.Nd indirect system call
.Sh SYNOPSIS
.Fd #include <sys/syscall.h>
.Fd #include <unistd.h>
.Ft int
.Fn syscall "int number" "..."
.Ft int
.Fn __syscall "quad_t number" "..."
.Sh DESCRIPTION
.Fn Syscall
performs the system call whose assembly language
interface has the specified
.Fa number
with the specified arguments.
Symbolic constants for system calls can be found in the header file
.Ao Pa sys/syscall.h Ac .
The
.Nm __syscall
form should be used when one or more of the parameters is a
64-bit argument to ensure that argument alignment is correct.
This system call is useful for testing new system calls that
do not have entries in the C library.
.Sh RETURN VALUES
The return values are defined by the system call being invoked.
In general, a 0 return value indicates success.
A -1 return value indicates an error,
and an error code is stored in
.Va errno .
.Sh BUGS
There is no way to simulate system calls that have multiple return values
such as
.Xr pipe 2 .
.Sh HISTORY
The
.Fn syscall
function call appeared in
.Bx 4.0 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: syscall.2,v 1.4 1995/02/27 12:38:53 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1980, 1991, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)syscall.2 8.1 (Berkeley) 6/16/93
	35	.\"
	36	.Dd June 16, 1993
	37	.Dt SYSCALL 2
	38	.Os BSD 4
	39	.Sh NAME
	40	.Nm syscall ,
	41	.Nm __syscall
	42	.Nd indirect system call
	43	.Sh SYNOPSIS
	44	.Fd #include <sys/syscall.h>
	45	.Fd #include <unistd.h>
	46	.Ft int
	47	.Fn syscall "int number" "..."
	48	.Ft int
	49	.Fn __syscall "quad_t number" "..."
	50	.Sh DESCRIPTION
	51	.Fn Syscall
	52	performs the system call whose assembly language
	53	interface has the specified
	54	.Fa number
	55	with the specified arguments.
	56	Symbolic constants for system calls can be found in the header file
	57	.Ao Pa sys/syscall.h Ac .
	58	The
	59	.Nm __syscall
	60	form should be used when one or more of the parameters is a
	61	64-bit argument to ensure that argument alignment is correct.
	62	This system call is useful for testing new system calls that
	63	do not have entries in the C library.
	64	.Sh RETURN VALUES
65	The return values are defined by the system call being invoked.
66	In general, a 0 return value indicates success.
67	A -1 return value indicates an error,
68	and an error code is stored in
69	.Va errno .
70	.Sh BUGS
71	There is no way to simulate system calls that have multiple return values
72	such as
73	.Xr pipe 2 .
74	.Sh HISTORY
75	The
76	.Fn syscall
77	function call appeared in
78	.Bx 4.0 .