1.\" Copyright (c) 2000 Kelly Yancey 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/share/man/man9/tvtohz.9,v 1.1.4.2 2001/12/17 11:30:19 ru Exp $ 26.\" $DragonFly: src/share/man/man9/tvtohz.9,v 1.3 2007/06/30 21:47:54 swildner Exp $ 27.\" 28.Dd June 30, 2007 29.Dt TVTOHZ 9 30.Os 31.Sh NAME 32.Nm tvtohz_high , 33.Nm tvtohz_low 34.Nd convert time interval to tick count 35.Sh SYNOPSIS 36.In sys/time.h 37.Ft int 38.Fn tvtohz_high "struct timeval *tv" 39.Ft int 40.Fn tvtohz_low "struct timeval *tv" 41.Sh DESCRIPTION 42The 43.Fn tvtohz_high 44and 45.Fn tvtohz_low 46functions accept a single argument 47.Fa tv 48which specifies the time interval over which to calculate the number 49of system ticks that would elapse. 50.Sh RETURN VALUES 51The 52.Fn tvtohz_high 53function returns the integral number of system ticks expected to elapse 54in the given interval. 55The return value is intended to be used in a clock interrupt timed operation 56and guaranteed to meet or exceed the requested time. 57The minimum return value is 1 tick and the function will average the 58calculation up. 59If any value greater than 0 microseconds is supplied, a value of at least 2 60will be returned to ensure that a near-term clock interrupt does not cause 61the timeout to occur (degenerately) early. 62.Pp 63The 64.Fn tvtohz_low 65function returns the uncompensated number of system ticks for the specified 66amount of time. 67A return value of 0 is possible if 68.Fa tv 69converts to less than 1 tick. 70.Pp 71If the reprensentation overflows, both functions return 72.Dv INT_MAX . 73.Sh FILES 74.Pa sys/kern/kern_clock.c 75.Sh SEE ALSO 76.Xr microtime 9 , 77.Xr microuptime 9 , 78.Xr timeout 9 79.Sh HISTORY 80The 81.Nm tvtohz 82function first appeared in 83.Fx 3.0 . 84It was split into 85.Nm 86and 87.Nm tvtohz_low 88by 89.An Matt Dillon 90in 91.Dx 1.0 . 92.Sh AUTHORS 93.An -nosplit 94This manual page was originally written by 95.An Kelly Yancey Aq kbyanc@posi.net 96and later updated by 97.An Sascha Wildner . 98