1.\" $NetBSD: timer_settime.2,v 1.4 2003/09/14 09:02:50 wiz Exp $ 2.\" 3.\" Copyright (c) 2003 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Christos Zoulas. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd September 13, 2003 38.Dt TIMER_SETTIME 2 39.Os 40.Sh NAME 41.Nm timer_settime , 42.Nm timer_gettime , 43.Nm timer_getoverrun 44.Nd process timer manipulation 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In time.h 49.Ft int 50.Fn timer_settime "timer_t timerid" "int flags" "const struct itimerspec * restrict tim" "struct itimerspec * restrict otim" 51.Ft int 52.Fn timer_gettime "timer_t timerid" "struct itimerspec *tim" 53.Ft int 54.Fn timer_getoverrun "timer_t timerid" 55.Sh DESCRIPTION 56The 57.Fn timer_settime 58sets the next expiration time of the timer with id 59.Ar timerid 60to the 61.Fa it_value 62specified in the 63.Ar tim 64argument. 65If the value is 0, the timer is disarmed. 66If the argument 67.Ar otim 68is not 69.Dv NULL 70the old timer settingas are returned. 71If the 72.Ar flags 73argument is set to 74.Dv TIMER_RELTIME 75then the expiration time is set to the value in nanoseconds specified 76in the 77.Ar tim 78argument from the time the call to 79.Fn timer_settime 80was made. 81If the 82.Ar flags 83argument is set to 84.Dv TIMER_ABSTIME 85then the expiration time is set to be equal to the difference between the 86clock associated with this timer, and the value specified in the 87.Ar tim 88argument. 89If that time has already passed, then the call succeeds, and the 90expiration notification occurs. 91.Pp 92If the 93.Fa it_interval 94of the 95.Ar tim 96argument is non-zero, then the timer reloads upon expiration. 97.Pp 98The 99.Fn timer_gettime 100function returns the current settings of the timer 101specified by the 102.Ar timerid 103argument in the 104.Ar tim 105argument. 106.Pp 107Only one notification event (signal) can be pending for a given timer 108and process. 109If a timer expires while the signal is still queued for delivery, then 110the overrun counter for that timer is increased. 111The counter can store values up to 112.Dv DELAYTIMER_MAX . 113When the signal is finally delivered to the process, then the 114.Fn timer_getoverrun 115function can be used to retrieve the overrun counter for the timer 116specified in the 117.Ar timerid 118argument. 119.Sh NOTES 120Expiration time values are always rounded up to the resolution of the timer, 121so a notification will never be sent before the requested time. 122Values returned in the 123.Ar otim 124argument of 125.Fn timer_settime 126or in the 127.Ar tim 128argment of 129.Fn timer_gettime 130are subject to the above rounding effect and might not exactly match the 131requested values by the user. 132.Sh RETURN VALUES 133If successful, the 134.Fn timer_gettime 135and 136.Fn timer_settime 137functions return 0, and the 138.Fn timer_getoverrun 139function returns the expiration overrun count for the specified timer. 140Otherwise, the functions return \-1, and set 141.Dv errno 142to indicate the error. 143.Sh ERRORS 144The 145.Fn timer_gettime , 146.Fn timer_getoverrun , 147and 148.Fn timer_settime 149functions will fail if: 150.Bl -tag -width Er 151.It Bq Er EINVAL 152The argument 153.Ar timerid 154does not correspond to a valid timer id as returned by 155.Fn timer_create 156or that timer id has been deleted by 157.Fn timer_delete . 158.El 159.Pp 160The 161.Fn timer_settime 162function will fail if: 163.Bl -tag -width Er 164.It Bq Er EINVAL 165A nanosecond field in the 166.Ar tim 167structure specified a value less than zero or greater than or equal to 10e9. 168.El 169.Sh SEE ALSO 170.Xr clock_gettime 2 , 171.Xr timer_create 2 , 172.Xr timer_delete 2 173.Sh STANDARDS 174.St -p1003.1b-93 , 175.St -p1003.1i-95 176