1.\" Copyright (c) 1986, 1991, 1993 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.\" From: @(#)ualarm.3 8.2 (Berkeley) 4/19/94 33.\" $FreeBSD: src/lib/libc/gen/ualarm.3,v 1.9.2.5 2001/12/14 18:33:51 ru Exp $ 34.\" 35.Dd April 19, 1994 36.Dt UALARM 3 37.Os 38.Sh NAME 39.Nm ualarm 40.Nd schedule signal after specified time 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft u_int 46.Fn ualarm "u_int microseconds" "u_int interval" 47.Sh DESCRIPTION 48.Bf -symbolic 49This is a simplified interface to 50.Xr setitimer 2 . 51.Ef 52.Pp 53The 54.Fn ualarm 55function 56waits a count of 57.Ar microseconds 58before asserting the terminating signal 59.Dv SIGALRM . 60System activity or time used in processing the call may cause a slight 61delay. 62.Pp 63If the 64.Fa interval 65argument is non-zero, the 66.Dv SIGALRM 67signal will be sent 68to the process every 69.Fa interval 70microseconds after the timer expires (e.g. after 71.Fa value 72microseconds have passed). 73.Pp 74Due to 75.Xr setitimer 2 76restriction the maximum number of 77.Ar microseconds 78and 79.Ar interval 80is limited to 100000000000000 81(in case this value fit in the unsigned integer). 82.Sh RETURN VALUES 83When the signal has successfully been caught, 84.Fn ualarm 85returns the amount of time left on the clock. 86.Sh NOTES 87A microsecond is 0.000001 seconds. 88.Sh SEE ALSO 89.Xr getitimer 2 , 90.Xr setitimer 2 , 91.Xr sigaction 2 , 92.Xr sigsuspend 2 , 93.Xr signal 3 , 94.Xr sleep 3 , 95.Xr usleep 3 96.Sh HISTORY 97The 98.Fn ualarm 99function appeared in 100.Bx 4.3 . 101