89 lines
2.4 KiB
Groff
89 lines
2.4 KiB
Groff
.\" $NetBSD: nullop.9,v 1.1 2010/07/25 21:05:13 jruoho Exp $
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.\"
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.\" Copyright (c) 2010 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Jukka Ruohonen.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd July 25, 2010
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.Dt NULLOP 9
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.Os
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.Sh NAME
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.Nm nullop
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.Nd dummy functions
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.Sh SYNOPSIS
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.In sys/systm.h
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.Ft int
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.Fn nullop "void *v"
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.Ft void
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.Fn voidop "void"
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.Ft int
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.Fn enodev "void"
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.Ft int
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.Fn enxio "void"
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.Ft int
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.Fn enoioctl "void"
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.Ft int
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.Fn enosys "void"
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.Ft int
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.Fn eopnotsupp "void"
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.Sh DESCRIPTION
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The
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.Fn nullop
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function provides a generic
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.Dq null operation .
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It always returns the value 0.
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The
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.Fn voidop
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function takes no arguments and does nothing.
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.Pp
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The
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.Fn enodev ,
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.Fn enxio ,
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.Fn enoioctl ,
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.Fn enosys ,
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and
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.Fn eopnotsupp
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functions always fail, returning
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.Er ENODEV ,
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.Er ENXIO ,
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.Er ENOTTY ,
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.Er ENOSYS ,
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and
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.Er EOPNOTSUPP ,
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respectively.
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.Sh EXAMPLES
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The following example demonstrates a case where
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.Fn nullop
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may be useful:
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.Bd -literal -offset indent
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uint64_t xc;
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\&...
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xc = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL);
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xc_wait(xc);
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.Ed
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