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.Dd July 30, 2018 29.Dt TIMERADD 3 30.Os 31.Sh NAME 32.Nm timeradd , 33.Nm timersub , 34.Nm timerclear , 35.Nm timerisset , 36.Nm timercmp , 37.Nm timespecadd , 38.Nm timespecsub , 39.Nm timespecclear , 40.Nm timespecisset , 41.Nm timespeccmp 42.Nd operations on timevals and timespecs 43.Sh SYNOPSIS 44.In sys/time.h 45.Ft void 46.Fn timeradd "struct timeval *a" "struct timeval *b" "struct timeval *res" 47.Ft void 48.Fn timersub "struct timeval *a" "struct timeval *b" "struct timeval *res" 49.Ft void 50.Fn timerclear "struct timeval *tvp" 51.Ft int 52.Fn timerisset "struct timeval *tvp" 53.Ft int 54.Fn timercmp "struct timeval *a" "struct timeval *b" CMP 55.Ft void 56.Fn timespecadd "struct timespec *a" "struct timespec *b" "struct timespec *res" 57.Ft void 58.Fn timespecsub "struct timespec *a" "struct timespec *b" "struct timespec *res" 59.Ft void 60.Fn timespecclear "struct timespec *ts" 61.Ft int 62.Fn timespecisset "struct timespec *ts" 63.Ft int 64.Fn timespeccmp "struct timespec *a" "struct timespec *b" CMP 65.Sh DESCRIPTION 66These macros are provided for manipulating 67.Fa timeval 68and 69.Fa timespec 70structures for use with the 71.Xr clock_gettime 2 , 72.Xr clock_settime 2 , 73.Xr gettimeofday 2 74and 75.Xr settimeofday 2 76calls. 77The 78.Fa timeval 79structure is defined in 80.In sys/time.h 81as: 82.Bd -literal 83struct timeval { 84 long tv_sec; /* seconds since Jan. 1, 1970 */ 85 long tv_usec; /* and microseconds */ 86}; 87.Ed 88And the 89.Fa timespec 90structure is defined in 91.In time.h 92as: 93.Bd -literal 94struct timespec { 95 time_t tv_sec; /* seconds */ 96 long tv_nsec; /* and nanoseconds */ 97}; 98.Ed 99.Pp 100.Fn timeradd 101and 102.Fn timespecadd 103add the time information stored in 104.Fa a 105to 106.Fa b 107and store the result in 108.Fa res . 109The results are simplified such that the value of 110.Fa res->tv_usec 111or 112.Fa res->tv_nsec 113is always less than 1 second. 114.Pp 115.Fn timersub 116and 117.Fn timespecsub 118subtract the time information stored in 119.Fa b 120from 121.Fa a 122and store the result 123in 124.Fa res . 125.Pp 126.Fn timerclear 127and 128.Fn timespecclear 129initialize their argument to midnight (0 hour) January 1st, 1970 (the Epoch). 130.Pp 131.Fn timerisset 132and 133.Fn timespecisset 134return true if their argument is set to any time value other than the Epoch. 135.Pp 136.Fn timercmp 137and 138.Fn timespeccmp 139compare 140.Fa a 141to 142.Fa b 143using the comparison operator given in 144.Fa CMP , 145and return the result of that comparison. 146.Sh SEE ALSO 147.Xr clock_gettime 2 , 148.Xr gettimeofday 2 149.Sh HISTORY 150The 151.Fn timeradd 152family of macros were imported from 153.Nx 1.1 , 154and appeared in 155.Fx 2.2.6 . 156The 157.Fn timespecadd 158family of macros were imported from 159.Nx 1.3 160into 161.Fx 3.0 , 162though they were not exposed to userland until 163.Fx 12.0 . 164