1.\" $NetBSD: alarm.3,v 1.20 2002/10/02 10:44:27 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)alarm.3 8.2 (Berkeley) 4/19/94 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.Fd #include \*[Lt]unistd.h\*[Gt] 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 59.Ar seconds 60after the call to 61.Fn alarm . 62If an alarm has already been set with 63.Fn alarm 64but has not been delivered, another call to 65.Fn alarm 66will supersede the prior call. 67The request 68.Fn alarm "0" 69voids the current 70alarm and the signal SIGALRM will not be delivered. 71The maximum number of 72.Ar seconds 73allowed 74is 2147483647. 75.Pp 76The return value of 77.Fn alarm 78is the amount of time left on the timer from a previous call to 79.Fn alarm . 80If no alarm is currently set, the return value is 0. 81If there is an error setting the timer, 82.Fn alarm 83returns ((unsigned int) -1). 84.Sh SEE ALSO 85.Xr setitimer 2 , 86.Xr sigaction 2 , 87.Xr sigsuspend 2 , 88.Xr signal 3 , 89.Xr sigvec 3 , 90.Xr sleep 3 , 91.Xr ualarm 3 , 92.Xr usleep 3 93.Sh STANDARDS 94The 95.Fn alarm 96function conforms to 97.St -p1003.1-90 . 98.Sh HISTORY 99An 100.Fn alarm 101function appeared in 102.At v7 . 103