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 specified 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
       terminated.

       Implementations may place limitations on the granularity of timer values. 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 .