mirror of https://github.com/GnoConsortium/gno.git
116 lines
3.8 KiB
Groff
116 lines
3.8 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)gettimeofday.2 8.1 (Berkeley) 6/4/93
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.\"
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.TH GETTIMEOFDAY 2 "19 December 1997" GNO "System Calls"
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.SH NAME
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.BR gettimeofday ,
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.BR settimeofday
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\- get/set date and time
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.SH SYNOPSIS
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#include <sys/time.h>
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.sp 1
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int
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\fBgettimeofday\fR (struct timeval *\fItp\fR, struct timezone *\fItzp\fR);
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.sp 1
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int
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\fBsettimeofday\fR (struct timeval *\fItp\fR, struct timezone *\fItzp\fR);
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.SH DESCRIPTION
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The system's notion of the current Greenwich time and the current time
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zone is obtained with the
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.BR gettimeofday
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call, and set with the
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.BR settimeofday
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call. The time is expressed in seconds and microseconds
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since midnight (0 hour), January 1, 1970. The resolution of the system
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clock is hardware dependent, and the time may be updated continuously or
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in ``ticks.'' If
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.I tp
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or
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.I tzp
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is NULL, the associated time
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information will not be returned or set.
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.LP
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The structures pointed to by
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.I tp
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and
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.I tzp
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are defined in <sys/time.h> as:
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.nf
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struct timeval {
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long tv_sec; /* seconds since Jan. 1, 1970 */
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long tv_usec; /* and microseconds */
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};
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struct timezone {
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int tz_minuteswest; /* of Greenwich */
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int tz_dsttime; /* type of dst correction to apply */
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};
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.fi
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.LP
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The
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.I timezone
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structure indicates the local time zone
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(measured in minutes of time westward from Greenwich),
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and a flag that, if nonzero, indicates that
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Daylight Saving time applies locally during
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the appropriate part of the year.
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.LP
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Only the super-user may set the time of day or time zone.
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.SH RETURN
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A 0 return value indicates that the call succeeded.
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A -1 return value indicates an error occurred, and in this
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case an error code is stored into the global variable
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.IR errno .
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.SH BUGS
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The GNO implementation does not set or make use of the time zone
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information pointed to by
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.IR tzp ,
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nor the
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.BR tv_usec
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field. The
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.BR gettimeofday
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call always returns zero in the
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.BR tv_usec
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field.
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.SH SEE ALSO
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.BR date (1),
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.BR adjtime (2),
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.BR ctime (3),
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.BR clocks (7),
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.BR timed (8)
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.SH HISTORY
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The
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.BR settimeofday
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function call appeared in 4.2BSD.
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