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GETITIMER(2)                  System Calls Manual                 GETITIMER(2)

NAME
       getitimer, setitimer - get and set value of interval timer

SYNOPSIS
       #include <sys/time.h>

       int getitimer(int which, struct itimerval *value)
       int setitimer(int which, const struct itimerval *value, struct itimerval *ovalue);

DESCRIPTION
       Getitimer  retrieves  the current value of the given interval timer, in
       value.

       Setitimer sets a new value for the given interval timer,  as  given  in
       value,  and, if ovalue is not set to NULL, stores the old value for the
       interval timer in ovalue.

       For both functions, the which parameter indicates which of the interval
       timers they work on; which can have one of the following values:

       ITIMER_REAL    A  timer  that  is  decremented  in  realtime.  When  it
                      expires, a SIGARLM signal is delivered to the process.

       ITIMER_VIRTUAL A timer that is decremented in process user  time.  When
                      it  expires,  a  SIGVTALRM  signal  is  delivered to the
                      process.

       ITIMER_PROF    A timer that is decremented in process user+system time.
                      When  it  expires,  a SIGPROF signal is delivered to the
                      process.

       The specified timer will first expire after the time specified  in  the
       'it_value'  field of the itimerval structure. Similarly, upon retrieval
       the 'it_value' field will contain the time after which the  timer  will
       expire.

       If   'it_value'   is   zero,  then  the  timer  is  disabled,  and  the
       'it_interval' field is  ignored  and  (upon  retrieval)  set  to  zero.
       Otherwise,  'it_interval'  contains the repetition interval after which
       the timer will repeatedly expire, starting from  the  moment  that  the
       timer  expires for the first time according to the 'it_value' value. If
       'it_interval' is set to zero, no repetition will occur.

       The maximum supported timeout value that setitimer accepts, depends  on
       the clock tick rate of the operating system.

       These  functions share their real-time timer with alarm(2).  Therefore,
       use of both types of functions in one program yields undefined results.

RETURN VALUES
       Upon successful completion, these  functions  return  0.  Otherwise,  a
       value of -1 is returned and errno is set to indicate the error.

ERRORS
       The functions will fail if any of the following occur:

       EINVAL         Either which is not one of the ITIMER_* constants above,
                      or one of the timeval structures in value contains a bad
                      or too large value.

       EFAULT         Bad value or ovalue address.

SEE ALSO
       alarm(2)

AUTHOR
       David van Moolenbroek <dcvmoole@cs.vu.nl>

4th Berkeley Distribution       April 14, 2006                    GETITIMER(2)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | AUTHOR