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+.\" 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.
+.\" 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
+.\" $FreeBSD$
+.\"
+.Dd June 16, 1993
+.Dt SYSCALL 2
+.Os
+.Sh NAME
+.Nm syscall ,
+.Nm __syscall
+.Nd indirect system call
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In sys/syscall.h
+.In unistd.h
+.Ft int
+.Fn syscall "int number" ...
+.Ft off_t
+.Fn __syscall "quad_t number" ...
+.Sh DESCRIPTION
+The
+.Fn syscall
+function
+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
+.In sys/syscall.h .
+The
+.Fn __syscall
+form should be used when one or more of the arguments 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 HISTORY
+The
+.Fn syscall
+function appeared in
+.Bx 4.0 .
+.Sh BUGS
+There is no way to simulate system calls that have multiple return values
+such as
+.Xr pipe 2 .