1.\" $NetBSD: syscall.2,v 1.11 2002/02/08 01:28:23 ross 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 39.Sh NAME 40.Nm syscall , 41.Nm __syscall 42.Nd indirect system call 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.Fd #include \*[Lt]sys/syscall.h\*[Gt] 47.Fd #include \*[Lt]unistd.h\*[Gt] 48.Ft int 49.Fn syscall "int number" "..." 50.Ft quad_t 51.Fn __syscall "quad_t number" "..." 52.Sh DESCRIPTION 53.Fn syscall 54performs the system call whose assembly language 55interface has the specified 56.Fa number 57with the specified arguments. 58Symbolic constants for system calls can be found in the header file 59.Ao Pa sys/syscall.h Ac . 60The 61.Nm __syscall 62form should be used when one or more of the parameters is a 6364-bit argument to ensure that argument alignment is correct. 64This system call is useful for testing new system calls that 65do not have entries in the C library. 66.Sh RETURN VALUES 67The return values are defined by the system call being invoked. 68In general, a 0 return value indicates success. 69A -1 return value indicates an error, 70and an error code is stored in 71.Va errno . 72.Sh HISTORY 73The 74.Fn syscall 75function call appeared in 76.Bx 4.0 . 77.Sh BUGS 78There is no way to simulate system calls that have multiple return values 79such as 80.Xr pipe 2 . 81.Pp 82Due to ABI implementation differences in passing struct or union 83type arguments to system calls between different processors, all 84system calls pass instead pointers to such structs or unions, even 85when the documentation of the system call mentions otherwise. The 86conversion between passing structs and unions is handled normally 87via userland stubs. The correct arguments for the kernel entry 88points for each system call can be found in the header file 89.Ao Pa sys/syscallargs.h Ac 90