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.\" $OpenBSD: time.3,v 1.16 2015/01/29 01:46:30 schwarze Exp $
.\"
.\" Copyright (c) 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd $Mdocdate: January 29 2015 $
.Dt TIME 3
.Os
.Sh NAME
.Nm time
.Nd get time of day
.Sh SYNOPSIS
.In time.h
.Ft time_t
.Fn time "time_t *tloc"
.Sh DESCRIPTION
The
.Fn time
function returns the value of time in seconds since 0 hours, 0 minutes,
0 seconds, January 1, 1970, Coordinated Universal Time (UTC).
.Pp
A copy of the time value may be saved to the area indicated by the
pointer
.Fa tloc .
If
.Fa tloc
is a null pointer, no value is stored.
.Sh RETURN VALUES
Upon successful completion,
.Fn time
returns the value of time.
Otherwise a value of
.Po Fa time_t Pc Ns -1
is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The following error codes may be set in
.Va errno :
.Bl -tag -width Er
.It Bq Er EFAULT
An argument address referenced invalid memory.
.El
.Sh SEE ALSO
.Xr clock_gettime 2 ,
.Xr gettimeofday 2 ,
.Xr ctime 3
.Sh HISTORY
A
.Fn time
system call first appeared in
.At v1
and used to return time in sixtieths of a second in 32 bits,
which was to guarantee a crisis every 2.26 years.
Since
.At v6 ,
.Fn time
scale was changed to seconds, extending the pre-crisis stagnation
period up to a total of 68 years.
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