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 1.9.2.6 2003/02/23 19:45:53 trhodes Exp $ 34.\" $DragonFly: src/lib/libc/gen/alarm.3,v 1.3 2007/09/08 20:50:49 swildner Exp $ 35.\" 36.Dd April 19, 1994 37.Dt ALARM 3 38.Os 39.Sh NAME 40.Nm alarm 41.Nd set signal timer alarm 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft unsigned int 47.Fn alarm "unsigned int seconds" 48.Sh DESCRIPTION 49.Bf -symbolic 50This interface is made obsolete by 51.Xr setitimer 2 . 52.Ef 53.Pp 54The 55.Fn alarm 56function sets a timer to deliver the signal 57.Dv SIGALRM 58to the calling process after the specified number of 59.Fa seconds . 60If an alarm has already been set with 61.Fn alarm 62but has not been delivered, another call to 63.Fn alarm 64will supersede the prior call. 65The request 66.Fn alarm "0" 67voids the current 68alarm and the signal 69.Dv SIGALRM 70will not be delivered. 71.Pp 72Due to 73.Xr setitimer 2 74restriction the maximum number of 75.Fa seconds 76allowed is 100000000. 77.Sh RETURN VALUES 78The return value of 79.Fn alarm 80is the amount of time left on the timer from a previous call to 81.Fn alarm . 82If no alarm is currently set, the return value is 0. 83.Sh SEE ALSO 84.Xr setitimer 2 , 85.Xr sigaction 2 , 86.Xr sigpause 2 , 87.Xr sigvec 2 , 88.Xr signal 3 , 89.Xr sleep 3 , 90.Xr ualarm 3 , 91.Xr usleep 3 92.\" .Sh STANDARDS 93.\" The 94.\" .Fn alarm 95.\" function conforms to 96.\" .St -p1003.1-90 . 97.Sh HISTORY 98An 99.Fn alarm 100function appeared in 101.At v7 . 102