CDF_EPOCH16
===========

The CDF_EPOCH16 procedure computes or breaks down a CDF_EPOCH16 value in a CDF 
file. When computing an epoch, any missing value is considered to be zero.

If you supply a value for the Epoch argument and set the BREAKDOWN_EPOCH 
keyword, CDF_EPOCH16 will compute the values of the Year, Month, Day, etc. and 
insert the values into the named variables you supply.

If you specify the Year (and optionally, the Month, Day, etc.) and set the 
COMPUTE_EPOCH keyword, CDF_EPOCH16 will compute the epoch and place the value 
in the named variable supplied as the Epoch parameter.

Note: You must set either the BREAKDOWN_EPOCH or COMPUTE_EPOCH keyword.
      The procedure allows input of an array of EPOCH16 values. Initially,
      it could only handle a single EPOCH16 value.


Examples

To compute the epoch value of September 20, 2005 at 3:05:46:02:156 am:

CDF_EPOCH16, epoch, 2005, 9, 20, 3, 5, 46, 27, 2, 156, $
   /COMPUTE_EPOCH

To break down the given epoch value into standard date components:

CDF_EPOCH16, epoch, yr, mo, dy, hr, min, sec, milli, micro, nano, pico, $
   /BREAKDOWN_EPOCH

Syntax

CDF_EPOCH16, Epoch, Year [, Month, Day, Hour, Minute, Second, Milli, Micro, $
                          Nano, Pico] [, /BREAKDOWN_EPOCH] [, /COMPUTE_EPOCH]

Note: To compute the epoch, the date/time componments can be either a single 
      value or an array of values. The output Epoch field can be a scalar or
      an array of values. To break down the epoch, the Epoch field can be a 
      scalar or an array of epoch values. Based on the input, the date/time 
      componments can be a single value each, or an array of values.

Arguments

Epoch

The Epoch value to be broken down, or a named variable that will contain the 
computed epoch will be placed. The Epoch value is the number of picoseconds 
since 01-Jan-0000 00:00:00.000.000.000.000.

Note: “Year zero” is a convention chosen by CDF to measure epoch values. This 
date is more commonly referred to as 1 BC. Remember that 1 BC was a leap year. 
The Epoch is defined as the number of picoseconds since 
01-Jan-0000 00:00:00.000.000.000.000, as computed using the CDF library’s 
internal date routines. The CDF date/time calculations do not take into 
account the changes to the Gregorian calendar, and cannot be directly converted 
into Julian date/times. To convert between CDF epochs and date/times, use the 
CDF_EPOCH16 routine with either the BREAKDOWN_EPOCH or CONVERT_EPOCH keywords.

Year

If COMPUTE_EPOCH is set, a four-digit integer representing the year.

If BREAKDOWN_EPOCH is set, a named variable that will contain the year.

Month

If COMPUTE_EPOCH is set, an integer between 1 and 12 representing the month. 
Alternately, you can set Month equal to zero, in which case the Day argument 
can take on any value between 1-366.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
month value.

Day

If COMPUTE_EPOCH is set, an integer between 1 and 31 representing the day of 
the month. Alternately, if the Month argument is set equal to zero, Day can be 
an integer between 1-366 representing the day of the year.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric day 
of the month value.

Hour

If COMPUTE_EPOCH is set, an integer between 0 and 23 representing the hour of 
the day.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric hour 
of the day value.

Minute

If COMPUTE_EPOCH is set, an integer between 0 and 59 representing the minute of 
the hour.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
minute of the hour value.

Second

If COMPUTE_EPOCH is set, an integer between 0 and 59 representing the second 
of the minute.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
second of the minute value.

Milli

If COMPUTE_EPOCH is set, an integer between 0 and 999 representing the 
millisecond.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
millisecond value.

Micro

If COMPUTE_EPOCH is set, an integer between 0 and 999 representing the 
microsecond.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
microsecond value.

Nano

If COMPUTE_EPOCH is set, an integer between 0 and 999 representing the 
nanosecond.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
nanosecond value.

Pico

If COMPUTE_EPOCH is set, an integer between 0 and 999 representing the 
picosecond.

If BREAKDOWN_EPOCH is set, a named variable that will contain the numeric 
picosecond value.

Keywords

BREAKDOWN_EPOCH

Set this keyword to break down the value of the Epoch argument into its 
component parts, storing the resulting year, month, day, etc. values in the 
variables specified by the corresponding arguments.

COMPUTE_EPOCH

Set this keyword to compute the value of Epoch from the values specified by 
the Year, Month, Day, etc. arguments.

Version History

6.3

Introduced

 

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