134 lines
4.4 KiB
Groff
134 lines
4.4 KiB
Groff
.\" $NetBSD: kpause.9,v 1.2 2007/10/28 21:33:23 rjs Exp $
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.\"
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.\" Copyright (c) 2006, 2007 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 Andrew Doran.
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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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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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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.\" ------------------------------------------------------------
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.Dd July 18, 2007
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.Dt KPAUSE 9
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.Os
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.\" ------------------------------------------------------------
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.Sh NAME
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.Nm kpause
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.Nd make the calling LWP sleep
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.\" ------------------------------------------------------------
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.Sh SYNOPSIS
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.In sys/proc.h
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.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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.Ft int
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.Fn kpause \
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"const char *wmesg" "bool intr" "int timeo" "kmutex_t *mtx"
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.\" ------------------------------------------------------------
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.Sh DESCRIPTION
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.Fn kpause
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makes the calling LWP sleep.
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It's similar to
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.Xr cv_timedwait_sig 9
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without the corresponding
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.Xr cv_signal 9 .
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.Pp
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.Fn kpause
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can wake up spontaneously.
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Callers should prepare to handle it.
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.Pp
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.Bl -tag -width wmesg
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.It Fa wmesg
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Specifies a string of no more than 8 characters that describes
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the resource or condition associated with the call of
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.Fn kpause .
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The kernel does not use this argument directly but makes it available for
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utilities such as
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.Xr ps 1
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to display.
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.It Fa intr
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If true, sleep interruptably.
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If the LWP recieves a signal, or is interrupted by another condition such
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as its containing process exiting, the wait is ended early and an error
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code returned.
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.It Fa timeo
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Specify a timeout.
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It is an architecture and system dependent value related to the number of
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clock interrupts per second.
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See
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.Xr hz 9
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for details.
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The
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.Xr mstohz 9
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macro can be used to convert a timeout expressed in milliseconds to
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one suitable for
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.Fn kpause .
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.Pp
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Zero means no timeout.
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.It Fa mtx
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Specifies a kernel mutex to be used as an interlock, and must be held by the
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calling LWP on entry to
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.Fn kpause .
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It will be released once the LWP has prepared to sleep, and will be reacquired
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before
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.Fn kpause
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returns.
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.Fn kpause
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will release it before sleeping and acquire before returning.
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.El
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.\" ------------------------------------------------------------
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.Sh RETURN VALUES
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.Fn kpause
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returns 0 when waking up spontaneously.
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Otherwise,
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It returns an error number.
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.\" ------------------------------------------------------------
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EWOULDBLOCK
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The timeout expired.
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.It Bq Er ERESTART
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.Fn kpause
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returned as a result of a signal with
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.Dv SA_RESTART
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property.
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.It Bq Er EINTR
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.Fn kpause
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returned due to other reasons.
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Typically as a result of a signal without
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.Dv SA_RESTART
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property.
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.El
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.\" ------------------------------------------------------------
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr errno 9 ,
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.Xr condvar 9 ,
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.Xr mstohz 9 ,
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.Xr hz 9
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