---
title: "CFCalendarGetOrdinalityOfUnit(_:_:_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfcalendargetordinalityofunit(_:_:_:_:)"
---

# CFCalendarGetOrdinalityOfUnit(_:_:_:_:)

Returns the ordinal number of a calendrical unit within a larger unit at a specified absolute time.

## Declaration

```swift
func CFCalendarGetOrdinalityOfUnit(_ calendar: CFCalendar!, _ smallerUnit: CFCalendarUnit, _ biggerUnit: CFCalendarUnit, _ at: CFAbsoluteTime) -> CFIndex
```

## Parameters

- `calendar`: The calendar to examine.
- `smallerUnit`: A calendar unit. For valid values see doc://com.apple.corefoundation/documentation/CoreFoundation/CFCalendarUnit.
- `biggerUnit`: A calendar unit. For valid values see doc://com.apple.corefoundation/documentation/CoreFoundation/CFCalendarUnit.
- `at`: An absolute time.

## Return Value

Return Value The ordinal number of the calendar unit specified by smallerUnit within the calendar unit specified by biggerUnit at the absolute time at. For example, the time 00:45 is in the first hour of the day, and for units Hour and Day respectively, the result would be 1.

## Discussion

Discussion If the biggerUnit parameter is not logically bigger than the smallerUnit parameter in the calendar, or the given combination of units does not make sense (or is a computation which is undefined), the result is kCFNotFound. Discussion The ordinality is in most cases not the same as the decomposed value of the unit. Typically return values are 1 and greater; an exception is the week-in-month calculation, which returns 0 for days before the first week in the month containing the date. Note that some computations can take a relatively long time to perform.

## See Also

### Getting Ranges of Units

- [CFCalendarGetRangeOfUnit(_:_:_:_:)](corefoundation/cfcalendargetrangeofunit(_:_:_:_:).md)
- [CFCalendarGetTimeRangeOfUnit(_:_:_:_:_:)](corefoundation/cfcalendargettimerangeofunit(_:_:_:_:_:).md)
- [CFCalendarGetMaximumRangeOfUnit(_:_:)](corefoundation/cfcalendargetmaximumrangeofunit(_:_:).md)
- [CFCalendarGetMinimumRangeOfUnit(_:_:)](corefoundation/cfcalendargetminimumrangeofunit(_:_:).md)