1.\" Copyright (c) 1999 Kelly Yancey <kbyanc@posi.net> 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.\" 3. Neither the name of the author nor the names of any co-contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.Dd August 11, 1999 31.Dt TIMERADD 3 32.Os 33.Sh NAME 34.Nm timeradd , 35.Nm timersub , 36.Nm timerclear , 37.Nm timerisset , 38.Nm timercmp 39.Nd operations on timevals 40.Sh SYNOPSIS 41.In sys/time.h 42.Ft void 43.Fn timeradd "struct timeval *a" "struct timeval *b" "struct timeval *res" 44.Ft void 45.Fn timersub "struct timeval *a" "struct timeval *b" "struct timeval *res" 46.Ft void 47.Fn timerclear "struct timeval *tvp" 48.Ft int 49.Fn timerisset "struct timeval *tvp" 50.Ft int 51.Fn timercmp "struct timeval *a" "struct timeval *b" CMP 52.Sh DESCRIPTION 53These macros are provided for manipulating 54.Fa timeval 55structures for use with the 56.Xr gettimeofday 2 57and 58.Xr settimeofday 2 59calls. 60The structure is defined in 61.In sys/time.h 62as: 63.Bd -literal 64struct timeval { 65 long tv_sec; /* seconds since Jan. 1, 1970 */ 66 long tv_usec; /* and microseconds */ 67}; 68.Ed 69.Pp 70.Fn timeradd 71adds the time information stored in 72.Fa a 73to 74.Fa b 75and stores the resulting 76.Vt timeval 77in 78.Fa res . 79The results are simplified such that the value of 80.Fa res->tv_usec 81is always less than 1,000,000 (1 second). 82.Pp 83.Fn timersub 84subtracts the time information stored in 85.Fa b 86from 87.Fa a 88and stores the resulting 89.Vt timeval 90in 91.Fa res . 92.Pp 93.Fn timerclear 94initializes 95.Fa tvp 96to midnight (0 hour) January 1st, 1970 (the Epoch). 97.Pp 98.Fn timerisset 99returns true if 100.Fa tvp 101is set to any time value other than the Epoch. 102.Pp 103.Fn timercmp 104compares 105.Fa a 106to 107.Fa b 108using the comparison operator given in 109.Fa CMP , 110and returns the result of that comparison. 111.Sh SEE ALSO 112.Xr gettimeofday 2 113.Sh HISTORY 114The 115.Fn timeradd 116family of macros were imported from 117.Nx 1.1 , 118and appeared in 119.Fx 2.2.6 . 120