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# CFStringLowercase(_:_:)

Changes all uppercase alphabetical characters in a CFMutableString to lowercase.

```
func CFStringLowercase(_ theString: CFMutableString!, _ locale: CFLocale!)
```

## Parameters

`theString`

The string to be lowercased. If this value is not a CFMutableString object, an assertion is raised.

`locale`

The locale to use when the lowercasing operation is performed. Prior to OS X v10.3 this parameter was an untyped pointer and not used.

    The locale argument affects the case mapping algorithm. For example, for the Turkish locale, case-insensitive compare matches “I” to “ı” (Unicode code point U+0131, Latin Small Dotless I), not the normal “i” character.

## Discussion

The `locale` parameter type changed from void * to CFLocaleRef in OS X v10.3.

---

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