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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd April 19, 1994 29.Dt UALARM 3 30.Os 31.Sh NAME 32.Nm ualarm 33.Nd schedule signal after specified time 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In unistd.h 38.Ft useconds_t 39.Fn ualarm "useconds_t microseconds" "useconds_t interval" 40.Sh DESCRIPTION 41.Bf -symbolic 42This is a simplified interface to 43.Xr setitimer 2 . 44.Ef 45.Pp 46The 47.Fn ualarm 48function 49waits a count of 50.Fa microseconds 51before asserting the terminating signal 52.Dv SIGALRM . 53System activity or time used in processing the call may cause a slight 54delay. 55.Pp 56If the 57.Fa interval 58argument is non-zero, the 59.Dv SIGALRM 60signal will be sent 61to the process every 62.Fa interval 63microseconds after the timer expires (e.g.\& after 64.Fa microseconds 65number of microseconds have passed). 66.Pp 67Due to 68.Xr setitimer 2 69restriction the maximum number of 70.Fa microseconds 71and 72.Fa interval 73is limited to 100000000000000 74(in case this value fits in the unsigned integer). 75.Sh RETURN VALUES 76When the signal has successfully been caught, 77.Fn ualarm 78returns the amount of time left on the clock. 79.Sh NOTES 80A microsecond is 0.000001 seconds. 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 sleep 3 , 89.Xr usleep 3 90.Sh HISTORY 91The 92.Fn ualarm 93function appeared in 94.Bx 4.3 . 95