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# CFCalendarGetRangeOfUnit(_:_:_:_:)

Returns the range of values that one unit can take on within a larger unit during which a specific absolute time occurs.

```
func CFCalendarGetRangeOfUnit(_ calendar: CFCalendar!, _ smallerUnit: CFCalendarUnit, _ biggerUnit: CFCalendarUnit, _ at: CFAbsoluteTime) -> CFRange
```

## Parameters

`calendar`

The calendar to examine.

`smallerUnit`

A calendar unit. For valid values see [`CFCalendarUnit`](/documentation/CoreFoundation/CFCalendarUnit).

`biggerUnit`

A calendar unit. For valid values see [`CFCalendarUnit`](/documentation/CoreFoundation/CFCalendarUnit).

`at`

An absolute time.

## Return Value

The range of values that the calendar unit specified by `smallerUnit` can take on within the calendar unit specified by `biggerUnit` that includes the absolute time `at`. For example, the range the Day unit can take on in the Month in which the absolute time lies.

## Discussion

If `biggerUnit` is not logically bigger than `smallerUnit` in the calendar, or the given combination of units does not make sense (or is a computation which is undefined), the result is `{kCFNotFound, kCFNotFound`}.

---

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