BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / gen / sleep.3

diff --git a/usr/src/lib/libc/gen/sleep.3 b/usr/src/lib/libc/gen/sleep.3
index f45366a..ee9b270 100644 (file)
--- a/usr/src/lib/libc/gen/sleep.3
+++ b/usr/src/lib/libc/gen/sleep.3
@@ -1,32 +1,83 @@
-.\" Copyright (c) 1980 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1986, 1991 Regents of the University of California.
+.\" All rights reserved.

 .\"
 .\"

-.\"    @(#)sleep.3     6.2 (Berkeley) 5/12/86
+.\" 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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 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.

 .\"
 .\"

-.TH SLEEP 3  "May 12, 1986"
-.UC 4
-.SH NAME
-sleep \- suspend execution for interval
-.SH SYNOPSIS
-.nf
-.B sleep(seconds)
-.B unsigned seconds;
-.fi
-.SH DESCRIPTION
-The current process is suspended from execution for the number
-of seconds specified by the argument.
-The actual suspension time may be up to 1 second less than
-that requested, because scheduled wakeups occur at fixed 1-second intervals,
-and an arbitrary amount longer because of other activity
-in the system.
-.PP
-The routine is implemented by setting an interval timer
-and pausing until it occurs.
-The previous state of this timer is saved and restored.
-If the sleep time exceeds the time to the expiration of the
-previous timer,
-the process sleeps only until the signal would have occurred, and the
-signal is sent 1 second later.
-.SH "SEE ALSO"
-setitimer(2), sigpause(2), usleep(3)
+.\" 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.
+.\"
+.\"     @(#)sleep.3    6.3 (Berkeley) 4/19/91
+.\"
+.Dd April 19, 1991
+.Dt SLEEP 3
+.Os
+.Sh NAME
+.Nm sleep
+.Nd suspend process execution for interval of seconds
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft int
+.Fn sleep "u_int seconds"
+.Sh DESCRIPTION
+The
+.Fn sleep
+function
+suspends execution of the calling process
+for
+.Fa seconds
+of time.
+System activity or time spent in processing the
+call may lengthen the sleep by a second.
+.Pp
+If a timer is already running on the process its state is saved.
+If the value
+.Fa seconds
+is more than or equal to the remaining clock time for the saved timer,
+the sleep time is set to
+the remaining clock time.
+The state of the previous timer
+is restored after
+.Fa seconds
+has passed.
+.Pp
+This function is implemented using
+.Xr setitimer 2 ;
+it requires eight system calls each time it is invoked.
+A similar but less compatible function can be obtained with a single
+.Xr select 2 ;
+such a function would not restart after signals, but would not interfere
+with other uses of
+.Xr setitimer .
+.Sh RETURN VALUES
+.Sh SEE ALSO
+.Xr setitimer 2 ,
+.Xr sigpause 2 ,
+.Xr usleep 3
+.Sh HISTORY
+A
+.Fn sleep
+function appeared in
+.At v7 .