mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
115 lines
3.5 KiB
Groff
115 lines
3.5 KiB
Groff
.\"
|
|
.\" Copyright (c) 1996 Joerg Wunsch
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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.
|
|
.\"
|
|
.\" $Id: sleep.9,v 1.4 1996/04/06 13:33:23 joerg Exp $
|
|
.\" "
|
|
.Dd April 3, 1996
|
|
.Os
|
|
.Dt SLEEP 9
|
|
.Sh NAME
|
|
.Nm sleep ,
|
|
.Nm tsleep ,
|
|
.Nm wakeup
|
|
.Nd wait for events
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/param.h>
|
|
.Fd #include <sys/systm.h>
|
|
.Fd #include <sys/proc.h>
|
|
.Fd #include <sys/errno.h>
|
|
.Ft int
|
|
.Fn tsleep "void *ident" "int priority" "char *wmesg" "int timo"
|
|
.Ft void
|
|
.Fn wakeup "void *ident"
|
|
.Ft int
|
|
.Fn sleep "void *ident" "int priority"
|
|
.Sh DESCRIPTION
|
|
The functions
|
|
.Fn tsleep
|
|
and
|
|
.Fn wakeup
|
|
handle event-based process blocking. If a process must wait for an
|
|
external event, it is put on sleep by
|
|
.Nm tsleep .
|
|
The parameter
|
|
.Ar ident
|
|
is an arbitrary address that uniquely identifies the event on which
|
|
the process is being asleep. All processes sleeping on a single
|
|
.Ar ident
|
|
are woken up later by
|
|
.Nm wakeup ,
|
|
often called from inside an interrupt routine, to indicate that the
|
|
resource the process was blocking on is available now.
|
|
.Pp
|
|
The parameter
|
|
.Ar wmesg
|
|
is a string describing the sleep condition for tools like
|
|
.Xr ps 1 .
|
|
Due to the limited space of those programs to display arbitrary strings,
|
|
this message should not be longer than 6 characters.
|
|
.Pp
|
|
.Nm Tsleep
|
|
is the general sleep call. Suspends the current process until a wakeup is
|
|
performed on the specified identifier. The process will then be made
|
|
runnable with the specified
|
|
.Ar priority .
|
|
Sleeps at most
|
|
.Ar timo
|
|
\&/ hz seconds (0 means no timeout). If
|
|
.Ar pri
|
|
includes the
|
|
.Dv PCATCH
|
|
flag, signals are checked before and after sleeping, else signals are
|
|
not checked. Returns 0 if awakened,
|
|
.Dv EWOULDBLOCK
|
|
if the timeout expires. If
|
|
.Dv PCATCH
|
|
is set and a signal needs to be delivered,
|
|
.Dv ERESTART
|
|
is returned if the current system call should be restarted if
|
|
possible, and
|
|
.Dv EINTR
|
|
is returned if the system call should be interrupted by the signal
|
|
.Pq return Dv EINTR .
|
|
.Pp
|
|
.Nm Sleep
|
|
is the traditional form. It doesn't let you specify a timeout nor a
|
|
.Ar wmesg ,
|
|
hence its use is deprecated.
|
|
.Sh RETURN VALUES
|
|
See above.
|
|
.Sh SEE ALSO
|
|
.Xr ps 1
|
|
.Sh HISTORY
|
|
The sleep/wakeup process synchronization mechanism is very old. It
|
|
appeared in a very early version of Unix.
|
|
.Pp
|
|
.Nm Tsleep
|
|
appeared in
|
|
.Bx 4.4 .
|
|
.Sh AUTHORS
|
|
This man page has been written by
|
|
.ie t J\(:org Wunsch.
|
|
.el Joerg Wunsch.
|