2012-11-15 12:06:41 +01:00
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.\" $NetBSD: ualarm.3,v 1.19 2011/05/02 17:34:05 jruoho Exp $
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2011-02-14 20:36:03 +01:00
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.\"
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.\" Copyright (c) 1986, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)ualarm.3 8.2 (Berkeley) 4/19/94
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.\"
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2012-11-15 12:06:41 +01:00
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.Dd May 2, 2011
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2011-02-14 20:36:03 +01:00
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.Dt UALARM 3
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.Os
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.Sh NAME
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.Nm ualarm
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.Nd schedule signal after specified time
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft useconds_t
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.Fn ualarm "useconds_t microseconds" "useconds_t interval"
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.Sh DESCRIPTION
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.Bf -symbolic
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This is a simplified interface to
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.Xr setitimer 2 .
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.Ef
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.Pp
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The
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.Fn ualarm
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function
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waits a count of
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.Ar microseconds
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before asserting the terminating signal
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.Dv SIGALRM .
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System activity or time used in processing the call may cause a slight
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delay.
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.Pp
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If the
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.Fa interval
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argument is non-zero, the
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.Dv SIGALRM
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signal will be sent
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to the process every
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.Fa interval
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microseconds after the timer expires (e.g. after
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.Fa microseconds
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microseconds have passed).
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.Sh RETURN VALUES
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When the signal has successfully been caught,
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.Fn ualarm
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returns the amount of time left on the clock.
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The maximum number of
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.Ar microseconds
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allowed
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is 2147483647.
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If there is an error setting the timer,
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.Fn ualarm
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returns ((useconds_t) -1).
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.Sh SEE ALSO
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.Xr getitimer 2 ,
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.Xr setitimer 2 ,
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.Xr sigaction 2 ,
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.Xr sigsuspend 2 ,
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.Xr alarm 3 ,
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.Xr signal 3 ,
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.Xr sigvec 3 ,
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.Xr sleep 3 ,
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.Xr usleep 3
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.Sh STANDARDS
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The
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.Fn ualarm
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function conforms to
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.St -p1003.1-2001 .
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However, the later
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.St -p1003.1-2008
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revision removed the function from the specification.
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2011-02-14 20:36:03 +01:00
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.Sh HISTORY
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The
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.Fn ualarm
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function appeared in
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.Bx 4.3 .
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