1.\" $NetBSD: mstohz.9,v 1.6 2009/10/19 18:41:09 bouyer Exp $ 2.\" 3.\" Copyright (c) 2002 Manuel Bouyer. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" 27.Dd April 4, 2002 28.Dt MSTOHZ 9 29.Os 30.Sh NAME 31.Nm mstohz 32.Nd convert milliseconds to system clock ticks 33.Sh SYNOPSIS 34.In sys/param.h 35.Ft int 36.Fn mstohz "int ms" 37.Sh DESCRIPTION 38.Nm 39can be used to convert time in milliseconds to system clock ticks, as used 40by the 41.Xr callout 9 42facility, in an integer-overflow safe way. 43.Pp 44This function is implemented as a define in the 45.Em \*[Lt]sys/param.h\*[Gt] 46header. 47Individual ports can have a processor-specific, more efficient 48version implemented in their 49.Em \*[Lt]machine/param.h\*[Gt] 50header as a define. 51.Sh RETURN VALUES 52The return value is the number of clock ticks for the specified value. 53.Sh SEE ALSO 54.Xr callout 9 55.Sh BUGS 56The machine-independent 57.Fn mstohz 58function does not make use of expensive 64-bit integer arithmetic, so 59the result will be rounded down to one second if the parameter is larger 60than 131072 milliseconds. 61