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.
@(#)time.3 8.1 (Berkeley) 6/4/93
.Dd April 29, 2024 .Dt TIME 3 .Os .Sh NAME .Nm time .Nd get time of day .Sh LIBRARY .Lb libc .Sh SYNOPSIS n 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.
p If .Fa tloc is not a null pointer, a copy of the time value is saved in .Fa *tloc .
p Upon successful completion, .Fn time returns the value of time. Otherwise a value of
o
o Fa time_t Pc Ns -1
c is returned and the global variable .Va errno is set to indicate the error. .Sh ERRORS No errors are defined. .Sh SEE ALSO .Xr gettimeofday 2 , .Xr ctime 3 .Sh STANDARDS The .Fn time function conforms to .St -p1003.1-90 . .Sh HISTORY A .Fn time function appeared in .At v2 . It returned a 32-bit value measuring sixtieths of a second, leading to rollover every 2.26 years. In .At v6 , the precision of .Fn time was changed to seconds, allowing 135.6 years between rollovers.
p In .Nx 6.0 the .Vt time_t type was changed to be 64 bits wide, including on 32-bit machines, making rollover a concern for the far distant future only. Note however that any code making the incorrect assumption that .Vt time_t is the same as .Vt long will fail on 32-bit machines in 2038.