napms.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1997 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
/*
* University Copyright- Copyright (c) 1982, 1986, 1988
* The Regents of the University of California
* All Rights Reserved
*
* University Acknowledgment- Portions of this document are derived from
* software developed by the University of California, Berkeley, and its
* contributors.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*LINTLIBRARY*/
#include "curses_inc.h"
#include <stdio.h>
#include <poll.h>
/*
* napms. Sleep for ms milliseconds. We don't expect a particularly good
* resolution - 60ths of a second is normal, 10ths might even be good enough,
* but the rest of the program thinks in ms because the unit of resolution
* varies from system to system. (In some countries, it's 50ths, for example.)
* Vaxen running 4.2BSD and 3B's use 100ths.
*
* Here are some reasonable ways to get a good nap.
*
* (1) Use the poll() or select() system calls in SVr3 or Berkeley 4.2BSD.
*
* (2) Use the 1/10th second resolution wait in the System V tty driver.
* It turns out this is hard to do - you need a tty line that is
* always unused that you have read permission on to sleep on.
*
* (3) Install the ft (fast timer) device in your kernel.
* This is a psuedo-device to which an ioctl will wait n ticks
* and then send you an alarm.
*
* (4) Install the nap system call in your kernel.
* This system call does a timeout for the requested number of ticks.
*
* (5) Write a routine that busy waits checking the time with ftime.
* Ftime is not present on SYSV systems, and since this busy waits,
* it will drag down response on your system. But it works.
*/
int
{
perror("poll");
return (OK);
}