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   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)