hrtalarm(3C)                                                   hrtalarm(3C)

NAME
     hrtalarm - high resolution timer alarm

SYNOPSIS
     #include <sys/hrtcntl.h>

     int hrtalarm(hrtcmdt *cmdp, int cmds);

DESCRIPTION
     hrtalarm() provides an interface for the alarm function of high reso-
     lution or interval timers. cmds determines the number of commands for
     the system call.

     The following hrtcmd structure is defined in <sys/hrtcntl.h> and is
     used by hrtalarm():

     typedef struct hrtcmd {
         int             hrtccmd;     /* A timer command        */
         int             hrtcclk;     /* Which clock to use     */
         hrtimet        hrtcint;     /* A time interval        */
         hrtimet        hrtctod;     /* A time of day          */
         int             hrtcflags;   /* Various flags          */
         int             hrtcerror;   /* An error code          */
         ecbt           hrtcecb;     /* An event control block */
     } hrtcmdt;

     hrtccmd supports the following command types:

          HRTBSD
               Starts a timer and sends an alarm signal when the time
               elapses.

          HRTRBSD
               Sends an alarm signal again when the time elapses.

          HRTBSDREP
               Sends an alarm signal again when the time elapses depending
               on the setting in the hrtctod field.

          HRTBSDPEND
               Calculates the remaining time before the alarm will be
               issued.

          HRTBSDCANCEL
               Removes an alarm from the queue.

     hrtcclk determines the clock type and signal issued with the HRTBSD
     and HRTRBSD commands:

          CLKSTD
               Standard real time clock. The SIGALRM signal is sent to the
               process when the set time elapses.



Page 1                       Reliant UNIX 5.44                Printed 11/98

hrtalarm(3C)                                                   hrtalarm(3C)

          CLKUSERVIRT
               Clock measuring process virtual time (user mode). The
               SIGVTALRM signal is sent to the process when the set time
               elapses.

          CLKPROCVIRT
               Clock measuring process virtual time and when the system is
               running on behalf of the process (user and system mode). The
               SIGPROF signal is sent to the process when the set time
               elapses.

     hrtcint determines the time interval, the time resolution and the
     fraction of the second.

RESULT
     hrtalarm() returns the number of successfully executed calls. For each
     executed command hrtcerror contains the error code or 0.

     EINVAL    cmds is not positive.

     EINVAL    Unknown timer command.

     EINVAL    Illegal hrtcclk value.

     EFAULT    cmdp points outside the allocated address space of the pro-
               cess.

     ENOPKG    The timer command is not supported.

     ERANGE    Value of hrtcint is less 0 or the interval is to small.

     EAGAIN    All timer structures are currently used.

NOTES
     The hrtsleep() and hrtcancel() functions are not supported and simply
     return the error ENOPKG.

SEE ALSO
     signal(2), getitimer(3C), hrtcntl(3C).















Page 2                       Reliant UNIX 5.44                Printed 11/98