BloombergLP::bdlt::CalendarUtil::shiftModifiedPrecedingIfValid

Load, into the specified result, the date of the chronologically latest business day that is on or before the specified original date, unless a date cannot be found in the same month, in which case load the chronologically earliest business day after the original date based on the specified calendar. Return 0 on success, and a non‐zero value, without modifying *result, if the original date is not within the valid range of calendar or a valid business date cannot be found according to the above algorithm within the valid range of calendar.