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.\" $DragonFly: src/lib/libc/gen/ualarm.3,v 1.2 2003/06/17 04:26:42 dillon Exp $ 35.\" 36.Dd April 19, 1994 37.Dt UALARM 3 38.Os 39.Sh NAME 40.Nm ualarm 41.Nd schedule signal after specified time 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft u_int 47.Fn ualarm "u_int microseconds" "u_int interval" 48.Sh DESCRIPTION 49.Bf -symbolic 50This is a simplified interface to 51.Xr setitimer 2 . 52.Ef 53.Pp 54The 55.Fn ualarm 56function 57waits a count of 58.Ar microseconds 59before asserting the terminating signal 60.Dv SIGALRM . 61System activity or time used in processing the call may cause a slight 62delay. 63.Pp 64If the 65.Fa interval 66argument is non-zero, the 67.Dv SIGALRM 68signal will be sent 69to the process every 70.Fa interval 71microseconds after the timer expires (e.g. after 72.Fa value 73microseconds have passed). 74.Pp 75Due to 76.Xr setitimer 2 77restriction the maximum number of 78.Ar microseconds 79and 80.Ar interval 81is limited to 100000000000000 82(in case this value fit in the unsigned integer). 83.Sh RETURN VALUES 84When the signal has successfully been caught, 85.Fn ualarm 86returns the amount of time left on the clock. 87.Sh NOTES 88A microsecond is 0.000001 seconds. 89.Sh SEE ALSO 90.Xr getitimer 2 , 91.Xr setitimer 2 , 92.Xr sigpause 2 , 93.Xr sigvec 2 , 94.Xr alarm 3 , 95.Xr signal 3 , 96.Xr sleep 3 , 97.Xr usleep 3 98.Sh HISTORY 99The 100.Fn ualarm 101function appeared in 102.Bx 4.3 . 103