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UALARM(3P)                 POSIX Programmer's Manual                UALARM(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       ualarm - set the interval timer
SYNOPSIS
       #include <unistd.h>
       useconds_t ualarm(useconds_t useconds, useconds_t interval);

DESCRIPTION
       The ualarm() function shall cause the SIGALRM signal  to  be  generated
       for the calling process after the number of realtime microseconds spec-
       ified by the useconds argument has elapsed.  When the interval argument
       is  non-zero,  repeated  timeout  notification  occurs with a period in
       microseconds specified by the interval argument.  If  the  notification
       signal,  SIGALRM, is not caught or ignored, the calling process is ter-
       minated.
       Implementations may place limitations on the granularity of timer  val-
       ues.  For  each interval timer, if the requested timer value requires a
       finer granularity than the implementation supports,  the  actual  timer
       value shall be rounded up to the next supported value.
       Interactions between ualarm() and any of the following are unspecified:

              alarm()
              nanosleep()
              setitimer()
              timer_create()
              timer_delete()
              timer_getoverrun()
              timer_gettime()
              timer_settime()
              sleep()
RETURN VALUE
       The ualarm() function shall return the number of microseconds remaining
       from the previous ualarm() call. If  no  timeouts  are  pending  or  if
       ualarm() has not previously been called, ualarm() shall return 0.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       Applications are recommended to use nanosleep() if the Timers option is
       supported,    or    setitimer(),    timer_create(),     timer_delete(),
       timer_getoverrun(), timer_gettime(), or timer_settime() instead of this
       function.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       alarm(),    nanosleep(),    setitimer(),    sleep(),    timer_create(),
       timer_delete(),  timer_getoverrun(),  the  Base  Definitions  volume of
       IEEE Std 1003.1-2001, <unistd.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version 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 .

IEEE/The Open Group                  2003                           UALARM(3P)