99 lines
3.1 KiB
Groff
99 lines
3.1 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993, 1994
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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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.\" @(#)alarm.3 8.2 (Berkeley) 4/19/94
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.\" $FreeBSD$
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.\"
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.Dd April 19, 1994
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.Dt ALARM 3
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.Os BSD 4
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.Sh NAME
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.Nm alarm
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.Nd set signal timer alarm
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <unistd.h>
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.Ft unsigned int
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.Fn alarm "unsigned int seconds"
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.Sh DESCRIPTION
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.Bf -symbolic
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This interface is made obsolete by setitimer(2).
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.Ef
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.Pp
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The
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.Fn alarm
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function sets a timer to deliver the signal
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.Dv SIGALRM
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to the calling process after the specified number of
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.Fa seconds .
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If an alarm has already been set with
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.Fn alarm
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but has not been delivered, another call to
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.Fn alarm
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will supersede the prior call.
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The request
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.Fn alarm "0"
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voids the current
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alarm and the signal SIGALRM will not be delivered.
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.Pp
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Due to
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.Xr setitimer 2
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restriction the maximum number of
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.Ar seconds
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allowed is 100000000.
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.Sh RETURN VALUES
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.Pp
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The return value of
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.Fn alarm
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is the amount of time left on the timer from a previous call to
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.Fn alarm .
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If no alarm is currently set, the return value is 0.
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.Sh SEE ALSO
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.Xr setitimer 2 ,
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.Xr sigaction 2 ,
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.Xr sigpause 2 ,
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.Xr sigvec 2 ,
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.Xr signal 3 ,
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.Xr sleep 3 ,
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.Xr ualarm 3 ,
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.Xr usleep 3
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.\" .Sh STANDARDS
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.\" The
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.\" .Fn alarm
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.\" function conforms to
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.\" .St -p1003.1-90 .
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.Sh HISTORY
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An
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.Fn alarm
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function appeared in
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.At v7 .
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