$DateDif

The $Datedif function returns the difference in days between two dates.

Syntax

The format of the $DateDif function is:

$DateDif(date-1-format, date-1, date-2-format, date-2, [defcent], [centsplt])

Where:

• date-1-format specifies the format of the first date. The format can be a combination of these elements:

  DD	Gregorian numeric day
  DDD	Julian numeric date
  MM	Numeric month
  MON	Abbreviated month name
  MONTH	Full month name
  YY	Last two digits of numeric year (assumes that the year prefix is 19)
  YYYY	Full numeric year
  CYY	The century, plus the year. Century (C) is a single digit, where 0 represents 1900, 1 represents 2000, and so on.

  Valid formats are:

  • A format that has a month, day, and year element
  • A Julian date format that has a year element and a day element in the format DDD

  Any EBCDIC characters except single quotes are allowed within the input format and appear unchanged in the output date. The input format can be as many as 32 characters in length.

• date-1 specifies the first date in the format specified by the date-1-format argument. The date can be as many as 36 characters in length.
• date-2-format specifies the format of the second date. The format requirements are the same as those for the date-1-format argument. This argument can be omitted but the comma after it is required. If this argument is omitted, $Datedif assumes that date-2 is in the same format as date-1.
• date-2 specifies the second date. The date must be either in the format specified in the date-2-format argument, or in the format specified in date-1-format if date-2-format is not specified. The date can be as many as 36 characters in length.
• The defcent argument (optional) specifies the DEFCENT value to use; it overrides all other DEFCENT and CENTSPLT parameter values. This argument cannot be specified with the centsplt argument, unless one of the values is NULL.
• The centsplt argument (optional) specifies the CENTSPLT value to use; it overrides all other DEFCENT and CENTSPLT parameter values. This argument cannot be specified with the defcent argument, unless one of the values is NULL.

Usage

Dates in differing centuries

In the following procedure, Date_Difference, $Datedif calculates the difference between dates twice. Before the first Print statement, the CUSTOM parameter is set to 1, so the century defaults to the current century. Before the second Print statement, the DEFCENT parameter is set to 20.

PROCEDURE DATE_DIFFERENCE RESET CUSTOM=1 Begin Print $Datedif('CYYDDD','96333','YY MM DD','97 06 22',%defcent,%centsplt) %defcent = 20 Print $Datedif('CYYDDD','096333','YY MM DD','97 06 22',%defcent,%centsplt) End END PROCEDURE

Separators and leading zeros

• The separators in each format must match the separators in the corresponding date. For example:

  $datedif('MON DD, YYYY','JAN 08, 1990','YY:DDD', '88:210')

• When necessary, pad the month or date in the date argument with leading zeros to match the length of corresponding format argument. For example:

  $datedif('YY DDD','90 034',,'90 007')

How $DateDif works

• If date1 is the same as date21, 0 is returned.
• If date1 is earlier than date2, a negative integer is returned.
• If date1 is later than date2, a positive integer is returned.
• If an error occurs, 99999999 is returned.

Example

The following statement:

Print $datedif('MMDDYY','010790',,'040891')

prints this value:

-456