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 July 30, 2018 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.Nm timespecadd , 40.Nm timespecsub , 41.Nm timespecclear , 42.Nm timespecisset , 43.Nm timespeccmp 44.Nd operations on timevals and timespecs 45.Sh SYNOPSIS 46.In sys/time.h 47.Ft void 48.Fn timeradd "struct timeval *a" "struct timeval *b" "struct timeval *res" 49.Ft void 50.Fn timersub "struct timeval *a" "struct timeval *b" "struct timeval *res" 51.Ft void 52.Fn timerclear "struct timeval *tvp" 53.Ft int 54.Fn timerisset "struct timeval *tvp" 55.Ft int 56.Fn timercmp "struct timeval *a" "struct timeval *b" CMP 57.Ft void 58.Fn timespecadd "struct timespec *a" "struct timespec *b" "struct timespec *res" 59.Ft void 60.Fn timespecsub "struct timespec *a" "struct timespec *b" "struct timespec *res" 61.Ft void 62.Fn timespecclear "struct timespec *ts" 63.Ft int 64.Fn timespecisset "struct timespec *ts" 65.Ft int 66.Fn timespeccmp "struct timespec *a" "struct timespec *b" CMP 67.Sh DESCRIPTION 68These macros are provided for manipulating 69.Fa timeval 70and 71.Fa timespec 72structures for use with the 73.Xr clock_gettime 2 , 74.Xr clock_settime 2 , 75.Xr gettimeofday 2 76and 77.Xr settimeofday 2 78calls. 79The 80.Fa timeval 81structure is defined in 82.In sys/time.h 83as: 84.Bd -literal 85struct timeval { 86 long tv_sec; /* seconds since Jan. 1, 1970 */ 87 long tv_usec; /* and microseconds */ 88}; 89.Ed 90And the 91.Fa timespec 92structure is defined in 93.In time.h 94as: 95.Bd -literal 96struct timespec { 97 time_t tv_sec; /* seconds */ 98 long tv_nsec; /* and nanoseconds */ 99}; 100.Ed 101.Pp 102.Fn timeradd 103and 104.Fn timespecadd 105add the time information stored in 106.Fa a 107to 108.Fa b 109and store the result in 110.Fa res . 111The results are simplified such that the value of 112.Fa res->tv_usec 113or 114.Fa res->tv_nsec 115is always less than 1 second. 116.Pp 117.Fn timersub 118and 119.Fn timespecsub 120subtract the time information stored in 121.Fa b 122from 123.Fa a 124and store the result 125in 126.Fa res . 127.Pp 128.Fn timerclear 129and 130.Fn timespecclear 131initialize their argument to midnight (0 hour) January 1st, 1970 (the Epoch). 132.Pp 133.Fn timerisset 134and 135.Fn timespecisset 136return true if their argument is set to any time value other than the Epoch. 137.Pp 138.Fn timercmp 139and 140.Fn timespeccmp 141compare 142.Fa a 143to 144.Fa b 145using the comparison operator given in 146.Fa CMP , 147and return the result of that comparison. 148.Sh SEE ALSO 149.Xr gettimeofday 2 , 150.Xr clock_gettime 2 151.Sh HISTORY 152The 153.Fn timeradd 154family of macros were imported from 155.Nx 1.1 , 156and appeared in 157.Fx 2.2.6 . 158The 159.Fn timespecadd 160family of macros were imported from 161.Nx 1.3 162into 163.Fx 3.0 , 164though they were not exposed to userland until 165.Fx 12.0 . 166