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.\" 34.Dd April 19, 1994 35.Dt ALARM 3 36.Os BSD 4 37.Sh NAME 38.Nm alarm 39.Nd set signal timer alarm 40.Sh SYNOPSIS 41.Fd #include <unistd.h> 42.Ft unsigned int 43.Fn alarm "unsigned int seconds" 44.Sh DESCRIPTION 45.Bf -symbolic 46This interface is made obsolete by setitimer(2). 47.Ef 48.Pp 49The 50.Fn alarm 51function sets a timer to deliver the signal 52.Dv SIGALRM 53to the calling process after the specified number of 54.Fa seconds . 55If an alarm has already been set with 56.Fn alarm 57but has not been delivered, another call to 58.Fn alarm 59will supersede the prior call. 60The request 61.Fn alarm "0" 62voids the current 63alarm and the signal SIGALRM will not be delivered. The maximum number of 64.Ar seconds 65allowed 66is 2147483647. 67.Pp 68The return value of 69.Fn alarm 70is the amount of time left on the timer from a previous call to 71.Fn alarm . 72If no alarm is currently set, the return value is 0. 73.Sh SEE ALSO 74.Xr sigaction 2 , 75.Xr setitimer 2 , 76.Xr sigpause 2 , 77.Xr sigvec 3 , 78.Xr signal 3 , 79.Xr sleep 3 , 80.Xr ualarm 3 , 81.Xr usleep 3 82.\" .Sh STANDARDS 83.\" The 84.\" .Fn alarm 85.\" function conforms to 86.\" .St -p1003.1-90 . 87.Sh HISTORY 88An 89.Fn alarm 90function appeared in 91.At v7 . 92