minix/lib/nbsd_libc/gen/time.3
Gianluca Guida b6cbf7203b Import unmodified NetBSD libc in trunk
This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.
2011-02-14 19:36:03 +00:00

112 lines
3.3 KiB
Groff

.\" $NetBSD: time.3,v 1.15 2010/04/24 01:35:50 dholland 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.
.\"
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.\" 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.
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.\" notice, this list of conditions and the following disclaimer in the
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.\"
.\" @(#)time.3 8.1 (Berkeley) 6/4/93
.\"
.Dd April 23, 2010
.Dt TIME 3
.Os
.Sh NAME
.Nm time
.Nd get time of day
.Sh LIBRARY
.Lb libc
.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.
.Pp
A copy of the time value may be saved to the area indicated by the
pointer
.Fa tloc .
If
.Fa tloc
is a
.Dv NULL
pointer, no value is stored.
.Pp
Upon successful completion,
.Fn time
returns the value of time.
Otherwise a value of
.Po
.Po Fa time_t Pc \-1
.Pc
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 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.
.Pp
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.