1.\" 2.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for 3.\" permission to reproduce portions of its copyrighted documentation. 4.\" Original documentation from The Open Group can be obtained online at 5.\" http://www.opengroup.org/bookstore/. 6.\" 7.\" The Institute of Electrical and Electronics Engineers and The Open 8.\" Group, have given us permission to reprint portions of their 9.\" documentation. 10.\" 11.\" In the following statement, the phrase ``this text'' refers to portions 12.\" of the system documentation. 13.\" 14.\" Portions of this text are reprinted and reproduced in electronic form 15.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, 16.\" Standard for Information Technology -- Portable Operating System 17.\" Interface (POSIX), The Open Group Base Specifications Issue 6, 18.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics 19.\" Engineers, Inc and The Open Group. In the event of any discrepancy 20.\" between these versions and the original IEEE and The Open Group 21.\" Standard, the original IEEE and The Open Group Standard is the referee 22.\" document. The original Standard can be obtained online at 23.\" http://www.opengroup.org/unix/online.html. 24.\" 25.\" This notice shall appear on any product containing this material. 26.\" 27.\" The Berkeley software License Agreement specifies the terms and conditions 28.\" for redistribution. 29.\" 30.\" 31.\" Copyright (c) 1980 Regents of the University of California. 32.\" All rights reserved. 33.\" Portions Copyright (c) 1992, X/Open Company Limited All Rights Reserved 34.\" Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved. 35.\" Copyright 2014 Garrett D'Amore <garrett@damore.org> 36.\" 37.Dd "Aug 16, 2014" 38.Dt UALARM 3C 39.Os 40.Sh NAME 41.Nm ualarm 42.Nd schedule signal after interval in microseconds 43.Sh SYNOPSIS 44.In unistd.h 45.Ft useconds_t 46.Fn ualarm "useconds_t useconds" "useconds_t interval" 47.Sh DESCRIPTION 48The 49.Fn ualarm 50function causes the 51.Dv SIGALRM 52signal to be generated for 53the calling process after the number of real-time microseconds specified by the 54.Fa useconds 55argument has elapsed. 56When the 57.Fa interval 58argument is 59non-zero, repeated timeout notification occurs with a period in microseconds 60specified by the 61.Fa interval 62argument. 63If the notification signal, 64.Dv SIGALRM , 65is not caught or ignored, the calling process is terminated. 66.Lp 67Because of scheduling delays, resumption of execution when the signal is caught 68may be delayed an arbitrary amount of time. 69.Lp 70Interactions between 71.Fn ualarm 72and either 73.Xr alarm 2 74or 75.Xr sleep 3C 76are unspecified. 77.Sh RETURN VALUES 78The 79.Fn ualarm 80function returns the number of microseconds remaining from 81the previous 82.Fn ualarm 83call. 84If no timeouts are pending or if 85.Fn ualarm 86has not previously been called, 87.Fn ualarm 88returns 0. 89.Sh ERRORS 90No errors are defined. 91.Sh USAGE 92The 93.Fn ualarm 94function is a simplified interface to 95.Xr setitimer 2 , 96and uses the 97.Dv ITIMER_REAL 98interval timer. 99It's use has been deprecated in favor of the 100.Xr timer_create 3C 101family of functions. 102.Sh INTERFACE STABILITY 103.Sy Obsolete Standard . 104.Sh SEE ALSO 105.Xr alarm 2 , 106.Xr setitimer 2 , 107.Xr sighold 3C , 108.Xr signal 3C , 109.Xr sleep 3C , 110.Xr timer_create 3C , 111.Xr usleep 3C , 112.Xr unistd.h 3HEAD , 113.Xr standards 7 114.Sh STANDARDS 115The 116.Fn ualarm 117function is available in the following compilation environments. 118See 119.Xr standards 7 . 120.Lp 121.Bl -bullet -compact 122.\".It 123.\".St -p1003.1-90 124.\".It 125.\".St -p1003.1b-93 126.\".It 127.\".St -p1003.1c-95 128.\".It 129.\".St -p1003.1-2001 130.\".It 131.\".St -xpg3 132.\".It 133.\".St -xpg4 134.It 135.St -xpg4.2 136.It 137.St -susv2 138.It 139.St -susv3 140.El 141.Lp 142It is marked obsolete in 143.St -susv3 , and was removed from 144.St -p1003.1-2008 . 145