setitimer(2)               DG/UX 4.30                setitimer(2)



     NAME
          setitimer - Sets one of the interval timers.

     SYNOPSIS
          #include <sys/time.h>

          int      setitimer  (which_timer, new_state_ptr, old_state_ptr)
          int                     which_timer;
          struct itimerval        *new_state_ptr;
          struct itimerval        *old_state_ptr;

     PARAMETERS
          which_timer    Specifies which of the three available timers
                         to set.  Can be ITIMER_REAL, ITIMER_VIRTUAL,
                         or ITIMER_PROF.

          new_state_ptr  The value to set in the specified timer.

          old_state_ptr  The previous value of the specified timer is
                         returned in old_state_ptr if non-zero.

     DESCRIPTION
          The setitimer system call can set one of three timers:
          ITIMER_REAL, ITIMER_VIRTUAL, or ITIMER_PROF.

          The ITIMER_REAL timer decrements in real-time.  A SIGALRM
          signal is delivered to the calling process when the timer
          expires.

          The ITIMER_VIRTUAL timer decrements when the process is
          running in user code.  A SIGVTALRM signal is delivered to
          the calling process when the timer expires.

          The ITIMER_PROF timer decrements both when the process is
          running in user code and when the system is running in
          behalf of the process.  It is designed to be used by
          interpreters in statistically profiling the execution of
          interpreted programs.  A SIGPROF signal is delivered to the
          calling process when the timer expires.

          The timeval structure defined in <sys/time.h> is of the
          form:

             struct itimerval
             {
             struct timeval  it_interval; /* timer interval
             struct timeval  it_value;    /* current value
             }

          If it_value is non-zero, it indicates the time to the next
          timer expiration.  If it_interval is non-zero, it specifies
          a value to be used in reloading it_value when the timer



     Licensed material--property of copyright holder(s)         Page 1

     setitimer(2)               DG/UX 4.30                setitimer(2)



          expires.  Setting it_value to 0 disables a timer.  Setting
          it_interval to 0 causes a timer to be disabled after its
          next expiration.

     RETURN VALUE
          0              Call was successful

          -1             An error occurred.  Errno is set to indicate
                         error.

     EXCEPTIONS
          Errno may be set to one of the following error codes:

          EFAULT         The new_state_ptr specified a bad address

          EINVAL  invalid argument

     SEE ALSO
          alarm(2), getitimer(2), sigvec(2).




































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