1.\" $MirOS: src/lib/libc/gen/time.3,v 1.3 2005/09/22 20:40:01 tg Exp $ 2.\" $OpenBSD: time.3,v 1.11 2005/07/22 03:16:58 jaredy Exp $ 3.\" 4.\" Copyright (c) 1989, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the American National Standards Committee X3, on Information 9.\" Processing Systems. 10.\" 11.\" Redistribution and use in source and binary forms, with or without 12.\" modification, are permitted provided that the following conditions 13.\" are met: 14.\" 1. Redistributions of source code must retain the above copyright 15.\" notice, this list of conditions and the following disclaimer. 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in the 18.\" documentation and/or other materials provided with the distribution. 19.\" 3. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.Dd June 4, 1993 36.Dt TIME 3 37.Os 38.Sh NAME 39.Nm time 40.Nd get time of day 41.Sh SYNOPSIS 42.Fd #include <time.h> 43.Ft time_t 44.Fn time "time_t *tloc" 45.Sh DESCRIPTION 46The 47.Fn time 48function returns the value of time in seconds since 0 hours, 0 minutes, 490 seconds, January 1, 1970 ("the Epoch"), Temps Atomique International 50(TAI), counting leap seconds. 51.Pp 52A copy of the time value may be saved to the area indicated by the 53pointer 54.Fa tloc . 55If 56.Fa tloc 57is a null pointer, no value is stored. 58.Pp 59Upon successful completion, 60.Fn time 61returns the value of time. 62Otherwise a value of 63.Po Fa time_t Pc Ns -1 64is returned and the global variable 65.Va errno 66is set to indicate the error. 67.Sh ERRORS 68The following error codes may be set in 69.Va errno : 70.Bl -tag -width Er 71.It Bq Er EFAULT 72An argument address referenced invalid memory. 73.El 74.Sh SEE ALSO 75.Xr gettimeofday 2 , 76.Xr ctime 3 77.Sh HISTORY 78A 79.Fn time 80function appeared in 81.At v2 82and used to return time in sixtieths of a second in 32 bits, 83which was to guarantee a crisis every 2.26 years. 84Since 85.At v6 , 86.Fn time 87scale was changed to seconds, extending the pre-crisis stagnation 88period up to a total of 68 years. 89.Pp 90On 91.Mx , 92the value equals the kernel time, or the result of 93.Xr gettimeofday 2 94with no timezone information provided. 95Counting leap seconds, instead of jumping over them, while 96calculating the result, violates POSIX, but is the only way 97to get legal and lawful time. 98.Pp 99Since 100.Mx 8 , 101the 102.Ft time_t 103type has been extended to 64 bit in order to prevent 104the year 2036 and 2038 crisises. 105