1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 1997 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * University Copyright- Copyright (c) 1982, 1986, 1988
32 * The Regents of the University of California
33 * All Rights Reserved
34 *
35 * University Acknowledgment- Portions of this document are derived from
36 * software developed by the University of California, Berkeley, and its
37 * contributors.
38 */
39
40 /*LINTLIBRARY*/
41
42 #include "curses_inc.h"
43 #include <stdio.h>
44 #include <sys/types.h>
45 #include <poll.h>
46
47 /*
48 * napms. Sleep for ms milliseconds. We don't expect a particularly good
49 * resolution - 60ths of a second is normal, 10ths might even be good enough,
50 * but the rest of the program thinks in ms because the unit of resolution
51 * varies from system to system. (In some countries, it's 50ths, for example.)
52 * Vaxen running 4.2BSD and 3B's use 100ths.
53 *
54 * Here are some reasonable ways to get a good nap.
55 *
56 * (1) Use the poll() or select() system calls in SVr3 or Berkeley 4.2BSD.
57 *
58 * (2) Use the 1/10th second resolution wait in the System V tty driver.
59 * It turns out this is hard to do - you need a tty line that is
60 * always unused that you have read permission on to sleep on.
61 *
62 * (3) Install the ft (fast timer) device in your kernel.
63 * This is a psuedo-device to which an ioctl will wait n ticks
64 * and then send you an alarm.
65 *
66 * (4) Install the nap system call in your kernel.
67 * This system call does a timeout for the requested number of ticks.
68 *
69 * (5) Write a routine that busy waits checking the time with ftime.
70 * Ftime is not present on SYSV systems, and since this busy waits,
71 * it will drag down response on your system. But it works.
72 */
73
74 int
napms(int ms)75 napms(int ms)
76 {
77 struct pollfd pollfd;
78
79 if (poll(&pollfd, 0L, ms) == -1)
80 perror("poll");
81 return (OK);
82 }
83