1 '\" te
2 .\" Copyright (c) 1980 Regents of the University of California. All rights reserved. The Berkeley software License Agreement specifies the terms and conditions for redistribution. Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved Portions Copyright (c) 1992,
3 .\" X/Open Company Limited All Rights Reserved
4 .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
5 .\" http://www.opengroup.org/bookstore/.
6 .\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.
7 .\" This notice shall appear on any product containing this material.
8 .TH UALARM 3C "Aug 14, 2002"
9 .SH NAME
10 ualarm \- schedule signal after interval in microseconds
11 .SH SYNOPSIS
12 .LP
13 .nf
14 #include <unistd.h>
15
16 \fBuseconds_t\fR \fBualarm\fR(\fBuseconds_t\fR \fIuseconds\fR, \fBuseconds_t\fR \fIinterval\fR);
17 .fi
18
19 .SH DESCRIPTION
20 .sp
21 .LP
22 The \fBualarm()\fR function causes the \fBSIGALRM\fR signal to be generated for
23 the calling process after the number of real-time microseconds specified by the
24 \fIuseconds\fR argument has elapsed. When the \fIinterval\fR argument is
25 non-zero, repeated timeout notification occurs with a period in microseconds
26 specified by the \fIinterval\fR argument. If the notification signal,
27 \fBSIGALRM\fR, is not caught or ignored, the calling process is terminated.
28 .sp
29 .LP
30 Because of scheduling delays, resumption of execution when the signal is caught
31 may be delayed an arbitrary amount of time.
32 .sp
33 .LP
34 Interactions between \fBualarm()\fR and either \fBalarm\fR(2) or
35 \fBsleep\fR(3C) are unspecified.
36 .SH RETURN VALUES
37 .sp
38 .LP
39 The \fBualarm()\fR function returns the number of microseconds remaining from
40 the previous \fBualarm()\fR call. If no timeouts are pending or if
41 \fBualarm()\fR has not previously been called, \fBualarm()\fR returns \fB0\fR.
42 .SH ERRORS
43 .sp
44 .LP
45 No errors are defined.
46 .SH USAGE
47 .sp
48 .LP
49 The \fBualarm()\fR function is a simplified interface to \fBsetitimer\fR(2),
50 and uses the \fBITIMER_REAL\fR interval timer.
51 .SH ATTRIBUTES
52 .sp
53 .LP
54 See \fBattributes\fR(5) for descriptions of the following attributes:
55 .sp
56
57 .sp
58 .TS
59 box;
60 c | c
61 l | l .
62 ATTRIBUTE TYPE ATTRIBUTE VALUE
63 _
64 Interface Stability Standard
65 .TE
66
67 .SH SEE ALSO
68 .sp
69 .LP
70 \fBalarm\fR(2), \fBsetitimer\fR(2), \fBsighold\fR(3C), \fBsignal\fR(3C),
71 \fBsleep\fR(3C), \fBusleep\fR(3C), \fBattributes\fR(5), \fBstandards\fR(5)
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1 .\" Copyright (c) 1980 Regents of the University of California. All rights reserved. The Berkeley software License Agreement specifies the terms and conditions for redistribution. Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved Portions Copyright (c) 1992,
2 .\" X/Open Company Limited All Rights Reserved
3 .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
4 .\" http://www.opengroup.org/bookstore/.
5 .\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.
6 .\" This notice shall appear on any product containing this material.
7 .Dd "Jul 22, 2014"
8 .Dt UALARM 3C
9 .Os
10 .Sh NAME
11 .Nm ualarm
12 .Nd schedule signal after interval in microseconds
13 .Sh SYNOPSIS
14 .In unistd.h
15 .Ft useconds_t
16 .Fn ualarm "Buseconds_t useconds" "useconds_t interval"
17 .Sh DESCRIPTION
18 The
19 .Fn ualarm
20 function causes the
21 .Dv SIGALRM
22 signal to be generated for
23 the calling process after the number of real-time microseconds specified by the
24 .Fa useconds argument has elapsed. When the
25 .Fa interval
26 argument is
27 non-zero, repeated timeout notification occurs with a period in microseconds
28 specified by the \fIinterval\fR argument. If the notification signal,
29 .Dv SIGALRM ,
30 is not caught or ignored, the calling process is terminated.
31 .Lp
32 Because of scheduling delays, resumption of execution when the signal is caught
33 may be delayed an arbitrary amount of time.
34 .Lp
35 Interactions between
36 .Fn ualarm
37 and either
38 .Xr alarm 2
39 or
40 .Xr sleep 3C
41 are unspecified.
42 .Sh RETURN VALUES
43 The
44 .Fn ualarm
45 function returns the number of microseconds remaining from
46 the previous
47 .Fn ualarm
48 call. If no timeouts are pending or if
49 .Fn ualarm
50 has not previously been called,
51 .Fn ualarm
52 returns 0.
53 .Sh ERRORS
54 No errors are defined.
55 .Sh USAGE
56 The
57 .Fn ualarm
58 function is a simplified interface to
59 .Xr setitimer 2 ,
60 and uses the
61 .Dv ITIMER_REAL
62 interval timer. It's use has been deprecated in favor of the
63 .Xr timer_create 3C
64 family of functions.
65 .Sh INTERFACE STABILITY
66 .Sy Obsolete Standard .
67 .Sh SEE ALSO
68 .Xr alarm 2 ,
69 .Xr setitimer(2),
70 .Xr sighold 3C ,
71 .Xr signal 3C ,
72 .Xr sleep 3C ,
73 .Xr timer_create 3C ,
74 .Xr usleep 3C ,
75 .Xr standards 5
76 .Sh STANDARDS
77 The
78 .Fn ualarm
79 function was introduced in
80 .Bx 4.3
81 and standardized in
82 .St -xpg4.2 .
83 It was subsequently obsoleted in
84 .St -p1003.1-2001
85 and removed from
86 .St -p1003.1-2008 .
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