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	1	.\" Copyright (c) 1980, 1991, 1993, 1994
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)alarm.3 8.2 (Berkeley) 4/19/94
	33	.\" $FreeBSD: src/lib/libc/gen/alarm.3,v 1.15 2001/10/01 16:08:50 ru Exp $
	34	.\"
	35	.Dd April 19, 1994
	36	.Dt ALARM 3
	37	.Os
	38	.Sh NAME
	39	.Nm alarm
	40	.Nd set signal timer alarm
	41	.Sh LIBRARY
	42	.Lb libc
	43	.Sh SYNOPSIS
	44	.In unistd.h
	45	.Ft unsigned int
	46	.Fn alarm "unsigned int seconds"
	47	.Sh DESCRIPTION
	48	.Bf -symbolic
	49	This interface is made obsolete by
	50	.Xr setitimer 2 .
	51	.Ef
	52	.Pp
	53	The
	54	.Fn alarm
	55	function sets a timer to deliver the signal
	56	.Dv SIGALRM
	57	to the calling process after the specified number of
	58	.Fa seconds .
	59	If an alarm has already been set with
	60	.Fn alarm
	61	but has not been delivered, another call to
	62	.Fn alarm
	63	will supersede the prior call.
	64	The request
	65	.Fn alarm "0"
	66	voids the current
	67	alarm and the signal SIGALRM will not be delivered.
	68	.Pp
	69	Due to
	70	.Xr setitimer 2
	71	restriction the maximum number of
	72	.Ar seconds
	73	allowed is 100000000.
	74	.Sh RETURN VALUES
	75	The return value of
	76	.Fn alarm
	77	is the amount of time left on the timer from a previous call to
	78	.Fn alarm .
	79	If no alarm is currently set, the return value is 0.
	80	.Sh SEE ALSO
	81	.Xr setitimer 2 ,
	82	.Xr sigaction 2 ,
	83	.Xr sigpause 2 ,
	84	.Xr sigvec 2 ,
	85	.Xr signal 3 ,
	86	.Xr sleep 3 ,
	87	.Xr ualarm 3 ,
	88	.Xr usleep 3
	89	.\" .Sh STANDARDS
	90	.\" The
	91	.\" .Fn alarm
	92	.\" function conforms to
	93	.\" .St -p1003.1-90 .
	94	.Sh HISTORY
	95	An
	96	.Fn alarm
	97	function appeared in
	98	.At v7 .