HP OpenVMS Systems

OpenVMS internal time format?

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The Question is:

 
What is the internal representation of the vmsdate datatype?
 

The Answer is :

 
  OpenVMS supports both a quadword "native" format, and an octaword UTC
  (Universal Coordinated Time; the UTC abbreviation is French) format.
  Both formats should be treated as opaque values, and the extensive
  suite of system services and Run-Time Library (RTL) routines should
  be used to access, manipulate, format, and parse time-related values.
  Support for American English as well as international time formats is
  provided with OpenVMS.
 
  For information on time and on the available routines, please see the
  _OpenVMS Programming Concepts_ manual in the OpenVMS documentation set,
  and for the lower-level timekeeping details of OpenVMS, please see the
  _Internals and Data Structures Manual_ available from Digital Press
  (http://www.bh.com/).
 
  The OpenVMS quadword "native" format is expressed as a signed integer.
  Positive values represent absolute dates as the number of 100 nanosecond
  "ticks" since midnight on 17th November 1858.  Negative values are delta
  times (offsets from the current time), and the offsets are also measured
  in 100 nanosecond "ticks".
 
  The internal format of the binary UTC time is not documented.
 
  If you are transfering time values between heterogeneous systems, use of
  the UTC standard text formats is recommended.
 
  OpenVMS Frequently Asked Questions (FAQ):
    http://www.openvms.digital.com/
 
  For related information:
    http://www.digital.com/year2000/
    http://www.openvms.digital.com/openvms/products/year-2000/leap.html
 

  

     

     
answer written or last revised on ( 31-DEC-1998 )
     
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