1.\" $NetBSD: ualarm.3,v 1.19 2011/05/02 17:34:05 jruoho Exp $ 2.\" 3.\" Copyright (c) 1986, 1991, 1993 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)ualarm.3 8.2 (Berkeley) 4/19/94 31.\" 32.Dd May 2, 2011 33.Dt UALARM 3 34.Os 35.Sh NAME 36.Nm ualarm 37.Nd schedule signal after specified time 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft useconds_t 43.Fn ualarm "useconds_t microseconds" "useconds_t interval" 44.Sh DESCRIPTION 45.Bf -symbolic 46This is a simplified interface to 47.Xr setitimer 2 . 48.Ef 49.Pp 50The 51.Fn ualarm 52function 53waits a count of 54.Ar microseconds 55before asserting the terminating signal 56.Dv SIGALRM . 57System activity or time used in processing the call may cause a slight 58delay. 59.Pp 60If the 61.Fa interval 62argument is non-zero, the 63.Dv SIGALRM 64signal will be sent 65to the process every 66.Fa interval 67microseconds after the timer expires (e.g. after 68.Fa microseconds 69microseconds have passed). 70.Sh RETURN VALUES 71When the signal has successfully been caught, 72.Fn ualarm 73returns the amount of time left on the clock. 74The maximum number of 75.Ar microseconds 76allowed 77is 2147483647. 78If there is an error setting the timer, 79.Fn ualarm 80returns ((useconds_t) -1). 81.Sh SEE ALSO 82.Xr getitimer 2 , 83.Xr setitimer 2 , 84.Xr sigaction 2 , 85.Xr sigsuspend 2 , 86.Xr alarm 3 , 87.Xr signal 3 , 88.Xr sigvec 3 , 89.Xr sleep 3 , 90.Xr usleep 3 91.Sh STANDARDS 92The 93.Fn ualarm 94function conforms to 95.St -p1003.1-2001 . 96However, the later 97.St -p1003.1-2008 98revision removed the function from the specification. 99.Sh HISTORY 100The 101.Fn ualarm 102function appeared in 103.Bx 4.3 . 104