---
title: "CFPreferencesSetAppValue(_:_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfpreferencessetappvalue(_:_:_:)"
---

# CFPreferencesSetAppValue(_:_:_:)

Adds, modifies, or removes a preference.

## Declaration

```swift
func CFPreferencesSetAppValue(_ key: CFString, _ value: CFPropertyList?, _ applicationID: CFString)
```

## Parameters

- `key`: The preference key whose value you wish to set.
- `value`: The value to set for the specified key and application. Pass NULL to remove the specified key from the application’s preferences.
- `applicationID`: The ID of the application whose preferences you wish to create or modify, typically doc://com.apple.corefoundation/documentation/CoreFoundation/kCFPreferencesCurrentApplication. Do not pass NULL or doc://com.apple.corefoundation/documentation/CoreFoundation/kCFPreferencesAnyApplication. Takes the form of a Java package name, com.foosoft.

## Discussion

Discussion New preference values are stored in the standard application preference location, ~/Library/Preferences/. When called with kCFPreferencesCurrentApplication, modifications are performed in the preference domain “Current User, Current Application, Any Host.” If you need to create preferences in some other domain, use the low-level function CFPreferencesSetValue(_:_:_:_:_:). You must call the CFPreferencesAppSynchronize(_:) function in order for your changes to be saved to permanent storage.

## See Also

### Setting Preference Values

- [CFPreferencesSetMultiple(_:_:_:_:_:)](corefoundation/cfpreferencessetmultiple(_:_:_:_:_:).md)
- [CFPreferencesSetValue(_:_:_:_:_:)](corefoundation/cfpreferencessetvalue(_:_:_:_:_:).md)