From m204wiki
Jump to navigation Jump to search

Add some days to datetime

Note: This $function require the Sir2000 User Language Tools product.

The $Sir_DateChg function expects a datetime format string, a datetime value string, and a number of days. It accepts an optional CENTSPAN value and an optional error control string. It returns the datetime string obtained by adding the indicated number of days to the input datetime; the return datetime string is in the same format as the input datetime string.

The $Sir_DateChg function is similar to the $DateChg function. However, the $DateChg function does not support the specification of a CENTSPAN argument.


%odat = $Sir_DateChg(fmt, dat, days, [span], errctl)


%odat Set to dat plus days 24-hour periods, unless an error is detected.
fmt Datetime format string, describes dat and %odat. Refer to Datetime string formats for an explanation of valid datetime formats and valid datetime values. Strict matching is used for fmt.
dat Datetime value string.
days Number of days to add to dat.
span Optional CENTSPAN value, default is -50. Refer to Using CENTSPAN.
errctl Optional error control string. Refer to Error handling control with DATE_ERR.


The following fragment prints the date one week after the run date:

%x = $sir_date('DAY Month, YYYY') Print $sir_datechg('DAY Month, YYYY', %x, 7)

Error conditions

$Sir_DateChg returns a string composed of all asterisks (*), whose length is the shorter of the length of the input date format string or 32, in the following error cases:

  • fmt is not a valid datetime format.
  • date does not match fmt or result date out of range.
  • days is omitted.
  • span contains an invalid CENTSPAN specification.

For more information about error handling, see Errors in datetime $functions.