NAME    [Toc]    [Back]

       ntp_gettime  -  Get  the date, time, and kernel time error
       values

SYNOPSIS    [Toc]    [Back]

       #include <sys/timex.h>

       int ntp_gettime(
               struct ntptimeval *tp );

PARAMETERS    [Toc]    [Back]

       Points to the ntptimeval structure in which information is
       returned.  The  ntptimeval  structure  is described in the
       <sys/timex.h> header file.

DESCRIPTION    [Toc]    [Back]

       The ntp_gettime() system call returns three read-only values
  in the ntptimeval structure. The ntptimeval structure
       members are as follows: The current system time  expressed
       as  a  Unix  timeval structure. The timeval structure consists
 of two 32-bit words: the first is the number of seconds
  past  1  January 1970, assuming no intervening leapsecond
 insertions or deletions; and the second is the number
  of  microseconds within the second.  The value of the
       time_maxerror kernel variable, which represents the  maximum
  error  of  the indicated time relative to the primary
       synchronization source,  in  microseconds.  For  NTP,  the
       value  is  initialized  to  the  synchronization distance,
       which is equal to the root dispersion  plus  one-half  the
       root delay. It is increased by a small amount (time_tolerance)
 each second to reflect the maximum  clock  frequency
       error.  This  variable  is  modified by the kernel, but is
       otherwise not used  by  the  kernel.   The  value  of  the
       time_esterror   kernel   variable,  which  represents  the
       expected error of the indicated time relative to the  primary
 synchronization source, in microseconds. For NTP, the
       value is determined as the root dispersion,  which  represents
  the best estimate of the actual error of the system
       clock based on its past behavior, together  with  observations
 of multiple clocks within the peer group. This variable
 is not used by the kernel.

RETURN VALUES    [Toc]    [Back]

       Upon  successful  completion,  a  value  of  0  (zero)  is
       returned.  Otherwise,  a value of -1 is returned and errno
       is set to indicate the error.

ERRORS    [Toc]    [Back]

       If the ntp_gettime() function fails, errno may be  set  to
       one  of the following values: The tp parameter points to a
       location outside of the allocated  address  space  of  the
       process.   The  kernel was configured without the NTP_TIME
       option.



                                                   ntp_gettime(2)