GI.Gio.Objects.Settings

The Settings class provides a convenient API for storing and retrieving application settings.

Reads and writes can be considered to be non-blocking. Reading settings with Settings is typically extremely fast: on approximately the same order of magnitude (but slower than) a HashTable lookup. Writing settings is also extremely fast in terms of time to return to your application, but can be extremely expensive for other threads and other processes. Many settings backends (including dconf) have lazy initialisation which means in the common case of the user using their computer without modifying any settings a lot of work can be avoided. For dconf, the D-Bus service doesn't even need to be started in this case. For this reason, you should only ever modify Settings keys in response to explicit user action. Particular care should be paid to ensure that modifications are not made during startup -- for example, when setting the initial value of preferences widgets. The built-in settingsBind functionality is careful not to write settings in response to notify signals as a result of modifications that it makes to widgets.

When creating a GSettings instance, you have to specify a schema that describes the keys in your settings and their types and default values, as well as some other information.

Normally, a schema has a fixed path that determines where the settings are stored in the conceptual global tree of settings. However, schemas can also be '[relocatable][gsettings-relocatable]', i.e. not equipped with a fixed path. This is useful e.g. when the schema describes an 'account', and you want to be able to store a arbitrary number of accounts.

Paths must start with and end with a forward slash character ('/') and must not contain two sequential slash characters. Paths should be chosen based on a domain name associated with the program or library to which the settings belong. Examples of paths are "/org/gtk/settings/file-chooser/" and "/ca/desrt/dconf-editor/". Paths should not start with "/apps/", "/desktop/" or "/system/" as they often did in GConf.

Unlike other configuration systems (like GConf), GSettings does not restrict keys to basic types like strings and numbers. GSettings stores values as GVariant, and allows any VariantType for keys. Key names are restricted to lowercase characters, numbers and '-'. Furthermore, the names must begin with a lowercase character, must not end with a '-', and must not contain consecutive dashes.

Similar to GConf, the default values in GSettings schemas can be localized, but the localized values are stored in gettext catalogs and looked up with the domain that is specified in the gettext-domain attribute of the <schemalist> or <schema> elements and the category that is specified in the l10n attribute of the <default> element. The string which is translated includes all text in the <default> element, including any surrounding quotation marks.

The l10n attribute must be set to messages or time, and sets the <https://www.gnu.org/software/gettext/manual/html_node/Aspects.html#index-locale-categories-1 locale category for translation>. The messages category should be used by default; use time for translatable date or time formats. A translation comment can be added as an XML comment immediately above the <default> element — it is recommended to add these comments to aid translators understand the meaning and implications of the default value. An optional translation context attribute can be set on the <default> element to disambiguate multiple defaults which use the same string.

For example: > > <!-- Translators: A list of words which are not allowed to be typed, in > GVariant serialization syntax. > See: https://developer.gnome.org/glib/stable/gvariant-text.html --> > l10n='messages' context='Banned words'[bad, words]/default

Translations of default values must remain syntactically valid serialized GVariants (e.g. retaining any surrounding quotation marks) or runtime errors will occur.

GSettings uses schemas in a compact binary form that is created by the [glib-compile-schemas][glib-compile-schemas] utility. The input is a schema description in an XML format.

A DTD for the gschema XML format can be found here: gschema.dtd

The [glib-compile-schemas][glib-compile-schemas] tool expects schema files to have the extension .gschema.xml.

At runtime, schemas are identified by their id (as specified in the id attribute of the <schema> element). The convention for schema ids is to use a dotted name, similar in style to a D-Bus bus name, e.g. "org.gnome.SessionManager". In particular, if the settings are for a specific service that owns a D-Bus bus name, the D-Bus bus name and schema id should match. For schemas which deal with settings not associated with one named application, the id should not use StudlyCaps, e.g. "org.gnome.font-rendering".

In addition to GVariant types, keys can have types that have enumerated types. These can be described by a <choice>, <enum> or <flags> element, as seen in the [example][schema-enumerated]. The underlying type of such a key is string, but you can use settingsGetEnum, settingsSetEnum, settingsGetFlags, settingsSetFlags access the numeric values corresponding to the string value of enum and flags keys.

An example for default value: > >schemalist > id="org.gtk.Test" path="/org/gtk/Test/" gettext-domain="test" > > name="greeting" type="s" > l10n="messages""Hello, earthlings"/default > summaryA greeting/summary > description > Greeting of the invading martians > /description > /key > > name="box" type="(ii)" > default(20,30)/default > /key > > name="empty-string" type="s" > default""/default > summaryEmpty strings have to be provided in GVariant form/summary > /key > > /schema >/schemalist

An example for ranges, choices and enumerated types: > >schemalist > > id="org.gtk.Test.myenum" > nick="first" value="1"/ > nick="second" value="2"/ > /enum > > id="org.gtk.Test.myflags" > nick="flag1" value="1"/ > nick="flag2" value="2"/ > nick="flag3" value="4"/ > /flags > > id="org.gtk.Test" > > name="key-with-range" type="i" > min="1" max="100"/ > default10/default > /key > > name="key-with-choices" type="s" > choices > value='Elisabeth'/ > value='Annabeth'/ > value='Joe'/ > /choices > aliases > value='Anna' target='Annabeth'/ > value='Beth' target='Elisabeth'/ > /aliases > defaultJoe/default > /key > > name='enumerated-key' enum='org.gtk.Test.myenum' > defaultfirst/default > /key > > name='flags-key' flags='org.gtk.Test.myflags' > default["flag1","flag2"]/default > /key > /schema >/schemalist

Vendor overrides

Default values are defined in the schemas that get installed by an application. Sometimes, it is necessary for a vendor or distributor to adjust these defaults. Since patching the XML source for the schema is inconvenient and error-prone, [glib-compile-schemas][glib-compile-schemas] reads so-called vendor override' files. These are keyfiles in the same directory as the XML schema sources which can override default values. The schema id serves as the group name in the key file, and the values are expected in serialized GVariant form, as in the following example: > > [org.gtk.Example] > key1=string > key2=1.5

glib-compile-schemas expects schema files to have the extension .gschema.override.

Binding

A very convenient feature of GSettings lets you bind Object properties directly to settings, using settingsBind. Once a GObject property has been bound to a setting, changes on either side are automatically propagated to the other side. GSettings handles details like mapping between GObject and GVariant types, and preventing infinite cycles.

This makes it very easy to hook up a preferences dialog to the underlying settings. To make this even more convenient, GSettings looks for a boolean property with the name "sensitivity" and automatically binds it to the writability of the bound setting. If this 'magic' gets in the way, it can be suppressed with the G_SETTINGS_BIND_NO_SENSITIVITY flag.

# {gsettings-relocatable}

A relocatable schema is one with no path attribute specified on its <schema> element. By using settingsNewWithPath, a Settings object can be instantiated for a relocatable schema, assigning a path to the instance. Paths passed to settingsNewWithPath will typically be constructed dynamically from a constant prefix plus some form of instance identifier; but they must still be valid GSettings paths. Paths could also be constant and used with a globally installed schema originating from a dependency library.

For example, a relocatable schema could be used to store geometry information for different windows in an application. If the schema ID was org.foo.MyApp.Window, it could be instantiated for paths /org/foo/MyApp/main/, /org/foo/MyApp/document-1/, /org/foo/MyApp/document-2/, etc. If any of the paths are well-known they can be specified as <child> elements in the parent schema, e.g.: > >id="org.foo.MyApp" path="/org/foo/MyApp/" > name="main" schema="org.foo.MyApp.Window"/ >/schema

# {gsettings-build-system}

GSettings comes with autotools integration to simplify compiling and installing schemas. To add GSettings support to an application, add the following to your configure.ac: > >GLIB_GSETTINGS

In the appropriate Makefile.am, use the following snippet to compile and install the named schema: > >gsettings_SCHEMAS = org.foo.MyApp.gschema.xml >EXTRA_DIST = $(gsettings_SCHEMAS) > >GSETTINGS_RULES

No changes are needed to the build system to mark a schema XML file for translation. Assuming it sets the gettext-domain attribute, a schema may be marked for translation by adding it to POTFILES.in, assuming gettext 0.19 is in use (the preferred method for translation): > >data/org.foo.MyApp.gschema.xml

Alternatively, if intltool 0.50.1 is in use: > >[type: gettextgsettings]dataorg.foo.MyApp.gschema.xml

GSettings will use gettext to look up translations for the <summary> and <description> elements, and also any <default> elements which have a l10n attribute set. Translations must not be included in the .gschema.xml file by the build system, for example by using intltool XML rules with a .gschema.xml.in template.

If an enumerated type defined in a C header file is to be used in a GSettings schema, it can either be defined manually using an <enum> element in the schema XML, or it can be extracted automatically from the C header. This approach is preferred, as it ensures the two representations are always synchronised. To do so, add the following to the relevant Makefile.am: > >gsettings_ENUM_NAMESPACE = org.foo.MyApp >gsettings_ENUM_FILES = my-app-enums.h my-app-misc.h

gsettings_ENUM_NAMESPACE specifies the schema namespace for the enum files, which are specified in gsettings_ENUM_FILES. This will generate a org.foo.MyApp.enums.xml file containing the extracted enums, which will be automatically included in the schema compilation, install and uninstall rules. It should not be committed to version control or included in EXTRA_DIST.

Exported types

newtype Settings

Memory-managed wrapper type.

Constructors

Settings (ManagedPtr Settings)

Instances

Eq Settings

Defined in GI.Gio.Objects.Settings

Methods

(==) :: Settings -> Settings -> Bool

(/=) :: Settings -> Settings -> Bool

GObject Settings

Defined in GI.Gio.Objects.Settings

Methods

gobjectType :: IO GType

IsGValue Settings

Convert Settings to and from GValue with toGValue and fromGValue.

Defined in GI.Gio.Objects.Settings

Methods

toGValue :: Settings -> IO GValue

fromGValue :: GValue -> IO Settings

HasParentTypes Settings

Defined in GI.Gio.Objects.Settings

type ParentTypes Settings

Defined in GI.Gio.Objects.Settings

type ParentTypes Settings = '[Object]

class (GObject o, IsDescendantOf Settings o) => IsSettings o

Type class for types which can be safely cast to Settings, for instance with toSettings.

Instances

(GObject o, IsDescendantOf Settings o) => IsSettings o

Defined in GI.Gio.Objects.Settings

toSettings :: (MonadIO m, IsSettings o) => o -> m Settings

Cast to Settings, for types for which this is known to be safe. For general casts, use castTo.

noSettings :: Maybe Settings

A convenience alias for Nothing :: Maybe Settings.

Methods

Overloaded methods

apply

settingsApply

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings instance

-> m ()

Applies any changes that have been made to the settings. This function does nothing unless settings is in 'delay-apply' mode; see settingsDelay. In the normal case settings are always applied immediately.

bind

settingsBind

Arguments

:: (HasCallStack, MonadIO m, IsSettings a, IsObject b)

=> a

settings: a Settings object

-> Text

key: the key to bind

-> b

object: a Object

-> Text

property: the name of the property to bind

-> [SettingsBindFlags]

flags: flags for the binding

-> m ()

Create a binding between the key in the settings object and the property property of object.

The binding uses the default GIO mapping functions to map between the settings and property values. These functions handle booleans, numeric types and string types in a straightforward way. Use g_settings_bind_with_mapping() if you need a custom mapping, or map between types that are not supported by the default mapping functions.

Unless the flags include SettingsBindFlagsNoSensitivity, this function also establishes a binding between the writability of key and the "sensitive" property of object (if object has a boolean property by that name). See settingsBindWritable for more details about writable bindings.

Note that the lifecycle of the binding is tied to object, and that you can have only one binding per object property. If you bind the same property twice on the same object, the second binding overrides the first one.

Since: 2.26

bindWritable

settingsBindWritable

Arguments

:: (HasCallStack, MonadIO m, IsSettings a, IsObject b)

=> a

settings: a Settings object

-> Text

key: the key to bind

-> b

object: a Object

-> Text

property: the name of a boolean property to bind

-> Bool

inverted: whether to 'invert' the value

-> m ()

Create a binding between the writability of key in the settings object and the property property of object. The property must be boolean; "sensitive" or "visible" properties of widgets are the most likely candidates.

Writable bindings are always uni-directional; changes of the writability of the setting will be propagated to the object property, not the other way.

When the inverted argument is True, the binding inverts the value as it passes from the setting to the object, i.e. property will be set to True if the key is not writable.

Note that the lifecycle of the binding is tied to object, and that you can have only one binding per object property. If you bind the same property twice on the same object, the second binding overrides the first one.

Since: 2.26

createAction

settingsCreateAction

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings

-> Text

key: the name of a key in settings

-> m Action

Returns: a new Action

Creates a Action corresponding to a given Settings key.

The action has the same name as the key.

The value of the key becomes the state of the action and the action is enabled when the key is writable. Changing the state of the action results in the key being written to. Changes to the value or writability of the key cause appropriate change notifications to be emitted for the action.

For boolean-valued keys, action activations take no parameter and result in the toggling of the value. For all other types, activations take the new value for the key (which must have the correct type).

Since: 2.32

delay

settingsDelay

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> m ()

Changes the Settings object into 'delay-apply' mode. In this mode, changes to settings are not immediately propagated to the backend, but kept locally until settingsApply is called.

Since: 2.26

getBoolean

settingsGetBoolean

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Bool

Returns: a boolean

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for booleans.

It is a programmer error to give a key that isn't specified as having a boolean type in the schema for settings.

Since: 2.26

getChild

settingsGetChild

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

name: the name of the child schema

-> m Settings

Returns: a 'child' settings object

Creates a child settings object which has a base path of base-path/@name, where base-path is the base path of settings.

The schema for the child settings object must have been declared in the schema of settings using a <child> element.

Since: 2.26

getDefaultValue

settingsGetDefaultValue

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the default value for

-> m (Maybe GVariant)

Returns: the default value

Gets the "default value" of a key.

This is the value that would be read if settingsReset were to be called on the key.

Note that this may be a different value than returned by settingsSchemaKeyGetDefaultValue if the system administrator has provided a default value.

Comparing the return values of settingsGetDefaultValue and settingsGetValue is not sufficient for determining if a value has been set because the user may have explicitly set the value to something that happens to be equal to the default. The difference here is that if the default changes in the future, the user's key will still be set.

This function may be useful for adding an indication to a UI of what the default value was before the user set it.

It is a programmer error to give a key that isn't contained in the schema for settings.

Since: 2.40

getDouble

settingsGetDouble

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Double

Returns: a double

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for doubles.

It is a programmer error to give a key that isn't specified as having a 'double' type in the schema for settings.

Since: 2.26

getEnum

settingsGetEnum

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Int32

Returns: the enum value

Gets the value that is stored in settings for key and converts it to the enum value that it represents.

In order to use this function the type of the value must be a string and it must be marked in the schema file as an enumerated type.

It is a programmer error to give a key that isn't contained in the schema for settings or is not marked as an enumerated type.

If the value stored in the configuration database is not a valid value for the enumerated type then this function will return the default value.

Since: 2.26

getFlags

settingsGetFlags

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Word32

Returns: the flags value

Gets the value that is stored in settings for key and converts it to the flags value that it represents.

In order to use this function the type of the value must be an array of strings and it must be marked in the schema file as an flags type.

It is a programmer error to give a key that isn't contained in the schema for settings or is not marked as a flags type.

If the value stored in the configuration database is not a valid value for the flags type then this function will return the default value.

Since: 2.26

getHasUnapplied

settingsGetHasUnapplied

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> m Bool

Returns: True if settings has unapplied changes

Returns whether the Settings object has any unapplied changes. This can only be the case if it is in 'delayed-apply' mode.

Since: 2.26

getInt

settingsGetInt

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Int32

Returns: an integer

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for 32-bit integers.

It is a programmer error to give a key that isn't specified as having a int32 type in the schema for settings.

Since: 2.26

getInt64

settingsGetInt64

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Int64

Returns: a 64-bit integer

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for 64-bit integers.

It is a programmer error to give a key that isn't specified as having a int64 type in the schema for settings.

Since: 2.50

getMapped

settingsGetMapped

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> SettingsGetMapping

mapping: the function to map the value in the settings database to the value used by the application

-> m (Ptr ())

Returns: the result, which may be Nothing

Gets the value that is stored at key in settings, subject to application-level validation/mapping.

You should use this function when the application needs to perform some processing on the value of the key (for example, parsing). The mapping function performs that processing. If the function indicates that the processing was unsuccessful (due to a parse error, for example) then the mapping is tried again with another value.

This allows a robust 'fall back to defaults' behaviour to be implemented somewhat automatically.

The first value that is tried is the user's setting for the key. If the mapping function fails to map this value, other values may be tried in an unspecified order (system or site defaults, translated schema default values, untranslated schema default values, etc).

If the mapping function fails for all possible values, one additional attempt is made: the mapping function is called with a Nothing value. If the mapping function still indicates failure at this point then the application will be aborted.

The result parameter for the mapping function is pointed to a gpointer which is initially set to Nothing. The same pointer is given to each invocation of mapping. The final value of that gpointer is what is returned by this function. Nothing is valid; it is returned just as any other value would be.

getRange

settingsGetRange

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings

-> Text

key: the key to query the range of

-> m GVariant

Deprecated: (Since version 2.40)Use settingsSchemaKeyGetRange instead.

Queries the range of a key.

Since: 2.28

getString

settingsGetString

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Text

Returns: a newly-allocated string

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for strings.

It is a programmer error to give a key that isn't specified as having a string type in the schema for settings.

Since: 2.26

getStrv

settingsGetStrv

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m [Text]

Returns: a newly-allocated, Nothing-terminated array of strings, the value that is stored at key in settings.

A convenience variant of g_settings_get() for string arrays.

It is a programmer error to give a key that isn't specified as having an array of strings type in the schema for settings.

Since: 2.26

getUint

settingsGetUint

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Word32

Returns: an unsigned integer

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for 32-bit unsigned integers.

It is a programmer error to give a key that isn't specified as having a uint32 type in the schema for settings.

Since: 2.30

getUint64

settingsGetUint64

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m Word64

Returns: a 64-bit unsigned integer

Gets the value that is stored at key in settings.

A convenience variant of g_settings_get() for 64-bit unsigned integers.

It is a programmer error to give a key that isn't specified as having a uint64 type in the schema for settings.

Since: 2.50

getUserValue

settingsGetUserValue

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the user value for

-> m (Maybe GVariant)

Returns: the user's value, if set

Checks the "user value" of a key, if there is one.

The user value of a key is the last value that was set by the user.

After calling settingsReset this function should always return Nothing (assuming something is not wrong with the system configuration).

It is possible that settingsGetValue will return a different value than this function. This can happen in the case that the user set a value for a key that was subsequently locked down by the system administrator -- this function will return the user's old value.

This function may be useful for adding a "reset" option to a UI or for providing indication that a particular value has been changed.

It is a programmer error to give a key that isn't contained in the schema for settings.

Since: 2.40

getValue

settingsGetValue

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the key to get the value for

-> m GVariant

Returns: a new GVariant

Gets the value that is stored in settings for key.

It is a programmer error to give a key that isn't contained in the schema for settings.

Since: 2.26

isWritable

settingsIsWritable

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

name: the name of a key

-> m Bool

Returns: True if the key name is writable

Finds out if a key can be written or not

Since: 2.26

listChildren

settingsListChildren

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> m [Text]

Returns: a list of the children on settings, in no defined order

Gets the list of children on settings.

The list is exactly the list of strings for which it is not an error to call settingsGetChild.

There is little reason to call this function from "normal" code, since you should already know what children are in your schema. This function may still be useful there for introspection reasons, however.

You should free the return value with strfreev when you are done with it.

listKeys

settingsListKeys

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> m [Text]

Returns: a list of the keys on settings, in no defined order

Deprecated: (Since version 2.46)Use g_settings_schema_list_keys instead().

Introspects the list of keys on settings.

You should probably not be calling this function from "normal" code (since you should already know what keys are in your schema). This function is intended for introspection reasons.

You should free the return value with strfreev when you are done with it.

listRelocatableSchemas

settingsListRelocatableSchemas

Arguments

:: (HasCallStack, MonadIO m)

=> m [Text]

Returns: a list of relocatable Settings schemas that are available, in no defined order. The list must not be modified or freed.

Deprecated: (Since version 2.40)Use settingsSchemaSourceListSchemas instead

Deprecated.

Since: 2.28

listSchemas

settingsListSchemas

Arguments

:: (HasCallStack, MonadIO m)

=> m [Text]

Returns: a list of Settings schemas that are available, in no defined order. The list must not be modified or freed.

Deprecated: (Since version 2.40)Use settingsSchemaSourceListSchemas instead.If you used settingsListSchemas to check for the presence ofa particular schema, use settingsSchemaSourceLookup insteadof your whole loop.

Deprecated.

Since: 2.26

new

settingsNew

Arguments

:: (HasCallStack, MonadIO m)

=> Text

schemaId: the id of the schema

-> m Settings

Returns: a new Settings object

Creates a new Settings object with the schema specified by schemaId.

Signals on the newly created Settings object will be dispatched via the thread-default MainContext in effect at the time of the call to settingsNew. The new Settings will hold a reference on the context. See mainContextPushThreadDefault.

Since: 2.26

newFull

settingsNewFull

Arguments

:: (HasCallStack, MonadIO m, IsSettingsBackend a)

=> SettingsSchema

schema: a SettingsSchema

-> Maybe a

backend: a SettingsBackend

-> Maybe Text

path: the path to use

-> m Settings

Returns: a new Settings object

Creates a new Settings object with a given schema, backend and path.

It should be extremely rare that you ever want to use this function. It is made available for advanced use-cases (such as plugin systems that want to provide access to schemas loaded from custom locations, etc).

At the most basic level, a Settings object is a pure composition of 4 things: a SettingsSchema, a SettingsBackend, a path within that backend, and a MainContext to which signals are dispatched.

This constructor therefore gives you full control over constructing Settings instances. The first 3 parameters are given directly as schema, backend and path, and the main context is taken from the thread-default (as per settingsNew).

If backend is Nothing then the default backend is used.

If path is Nothing then the path from the schema is used. It is an error if path is Nothing and the schema has no path of its own or if path is non-Nothing and not equal to the path that the schema does have.

Since: 2.32

newWithBackend

settingsNewWithBackend

Arguments

:: (HasCallStack, MonadIO m, IsSettingsBackend a)

=> Text

schemaId: the id of the schema

-> a

backend: the SettingsBackend to use

-> m Settings

Returns: a new Settings object

Creates a new Settings object with the schema specified by schemaId and a given SettingsBackend.

Creating a Settings object with a different backend allows accessing settings from a database other than the usual one. For example, it may make sense to pass a backend corresponding to the "defaults" settings database on the system to get a settings object that modifies the system default settings instead of the settings for this user.

Since: 2.26

newWithBackendAndPath

settingsNewWithBackendAndPath

Arguments

:: (HasCallStack, MonadIO m, IsSettingsBackend a)

=> Text

schemaId: the id of the schema

-> a

backend: the SettingsBackend to use

-> Text

path: the path to use

-> m Settings

Returns: a new Settings object

Creates a new Settings object with the schema specified by schemaId and a given SettingsBackend and path.

This is a mix of settingsNewWithBackend and settingsNewWithPath.

Since: 2.26

newWithPath

settingsNewWithPath

Arguments

:: (HasCallStack, MonadIO m)

=> Text

schemaId: the id of the schema

-> Text

path: the path to use

-> m Settings

Returns: a new Settings object

Creates a new Settings object with the relocatable schema specified by schemaId and a given path.

You only need to do this if you want to directly create a settings object with a schema that doesn't have a specified path of its own. That's quite rare.

It is a programmer error to call this function for a schema that has an explicitly specified path.

It is a programmer error if path is not a valid path. A valid path begins and ends with '/' and does not contain two consecutive '/' characters.

Since: 2.26

rangeCheck

settingsRangeCheck

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings

-> Text

key: the key to check

-> GVariant

value: the value to check

-> m Bool

Returns: True if value is valid for key

Deprecated: (Since version 2.40)Use settingsSchemaKeyRangeCheck instead.

Checks if the given value is of the correct type and within the permitted range for key.

Since: 2.28

reset

settingsReset

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of a key

-> m ()

Resets key to its default value.

This call resets the key, as much as possible, to its default value. That might be the value specified in the schema or the one set by the administrator.

revert

settingsRevert

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings instance

-> m ()

Reverts all non-applied changes to the settings. This function does nothing unless settings is in 'delay-apply' mode; see settingsDelay. In the normal case settings are always applied immediately.

Change notifications will be emitted for affected keys.

setBoolean

settingsSetBoolean

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Bool

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for booleans.

It is a programmer error to give a key that isn't specified as having a boolean type in the schema for settings.

Since: 2.26

setDouble

settingsSetDouble

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Double

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for doubles.

It is a programmer error to give a key that isn't specified as having a 'double' type in the schema for settings.

Since: 2.26

setEnum

settingsSetEnum

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: a key, within settings

-> Int32

value: an enumerated value

-> m Bool

Returns: True, if the set succeeds

Looks up the enumerated type nick for value and writes it to key, within settings.

It is a programmer error to give a key that isn't contained in the schema for settings or is not marked as an enumerated type, or for value not to be a valid value for the named type.

After performing the write, accessing key directly with settingsGetString will return the 'nick' associated with value.

setFlags

settingsSetFlags

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: a key, within settings

-> Word32

value: a flags value

-> m Bool

Returns: True, if the set succeeds

Looks up the flags type nicks for the bits specified by value, puts them in an array of strings and writes the array to key, within settings.

It is a programmer error to give a key that isn't contained in the schema for settings or is not marked as a flags type, or for value to contain any bits that are not value for the named type.

After performing the write, accessing key directly with settingsGetStrv will return an array of 'nicks'; one for each bit in value.

setInt

settingsSetInt

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Int32

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for 32-bit integers.

It is a programmer error to give a key that isn't specified as having a int32 type in the schema for settings.

Since: 2.26

setInt64

settingsSetInt64

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Int64

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for 64-bit integers.

It is a programmer error to give a key that isn't specified as having a int64 type in the schema for settings.

Since: 2.50

setString

settingsSetString

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Text

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for strings.

It is a programmer error to give a key that isn't specified as having a string type in the schema for settings.

Since: 2.26

setStrv

settingsSetStrv

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Maybe [Text]

value: the value to set it to, or Nothing

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for string arrays. If value is Nothing, then key is set to be the empty array.

It is a programmer error to give a key that isn't specified as having an array of strings type in the schema for settings.

Since: 2.26

setUint

settingsSetUint

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Word32

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for 32-bit unsigned integers.

It is a programmer error to give a key that isn't specified as having a uint32 type in the schema for settings.

Since: 2.30

setUint64

settingsSetUint64

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> Word64

value: the value to set it to

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

A convenience variant of g_settings_set() for 64-bit unsigned integers.

It is a programmer error to give a key that isn't specified as having a uint64 type in the schema for settings.

Since: 2.50

setValue

settingsSetValue

Arguments

:: (HasCallStack, MonadIO m, IsSettings a)

=> a

settings: a Settings object

-> Text

key: the name of the key to set

-> GVariant

value: a GVariant of the correct type

-> m Bool

Returns: True if setting the key succeeded, False if the key was not writable

Sets key in settings to value.

It is a programmer error to give a key that isn't contained in the schema for settings or for value to have the incorrect type, per the schema.

If value is floating then this function consumes the reference.

Since: 2.26

sync

settingsSync :: (HasCallStack, MonadIO m) => m ()

Ensures that all pending operations are complete for the default backend.

Writes made to a Settings are handled asynchronously. For this reason, it is very unlikely that the changes have it to disk by the time g_settings_set() returns.

This call will block until all of the writes have made it to the backend. Since the mainloop is not running, no change notifications will be dispatched during this call (but some may be queued by the time the call is done).

unbind

settingsUnbind

Arguments

:: (HasCallStack, MonadIO m, IsObject a)

=> a

object: the object

-> Text

property: the property whose binding is removed

-> m ()

Removes an existing binding for property on object.

Note that bindings are automatically removed when the object is finalized, so it is rarely necessary to call this function.

Since: 2.26

Properties

backend

The name of the context that the settings are stored in.

constructSettingsBackend :: (IsSettings o, MonadIO m, IsSettingsBackend a) => a -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “backend” property. This is rarely needed directly, but it is used by new.

getSettingsBackend :: (MonadIO m, IsSettings o) => o -> m (Maybe SettingsBackend)

Get the value of the “backend” property. When overloading is enabled, this is equivalent to

get settings #backend

delayApply

Whether the Settings object is in 'delay-apply' mode. See settingsDelay for details.

Since: 2.28

getSettingsDelayApply :: (MonadIO m, IsSettings o) => o -> m Bool

Get the value of the “delay-apply” property. When overloading is enabled, this is equivalent to

get settings #delayApply

hasUnapplied

If this property is True, the Settings object has outstanding changes that will be applied when settingsApply is called.

getSettingsHasUnapplied :: (MonadIO m, IsSettings o) => o -> m Bool

Get the value of the “has-unapplied” property. When overloading is enabled, this is equivalent to

get settings #hasUnapplied

path

The path within the backend where the settings are stored.

constructSettingsPath :: (IsSettings o, MonadIO m) => Text -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “path” property. This is rarely needed directly, but it is used by new.

getSettingsPath :: (MonadIO m, IsSettings o) => o -> m (Maybe Text)

Get the value of the “path” property. When overloading is enabled, this is equivalent to

get settings #path

schema

The name of the schema that describes the types of keys for this Settings object.

The type of this property is *not* SettingsSchema. SettingsSchema has only existed since version 2.32 and unfortunately this name was used in previous versions to refer to the schema ID rather than the schema itself. Take care to use the 'settings-schema' property if you wish to pass in a SettingsSchema.

constructSettingsSchema :: (IsSettings o, MonadIO m) => Text -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “schema” property. This is rarely needed directly, but it is used by new.

getSettingsSchema :: (MonadIO m, IsSettings o) => o -> m (Maybe Text)

Get the value of the “schema” property. When overloading is enabled, this is equivalent to

get settings #schema

schemaId

The name of the schema that describes the types of keys for this Settings object.

constructSettingsSchemaId :: (IsSettings o, MonadIO m) => Text -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “schema-id” property. This is rarely needed directly, but it is used by new.

getSettingsSchemaId :: (MonadIO m, IsSettings o) => o -> m (Maybe Text)

Get the value of the “schema-id” property. When overloading is enabled, this is equivalent to

get settings #schemaId

settingsSchema

The SettingsSchema describing the types of keys for this Settings object.

Ideally, this property would be called 'schema'. SettingsSchema has only existed since version 2.32, however, and before then the 'schema' property was used to refer to the ID of the schema rather than the schema itself. Take care.

constructSettingsSettingsSchema :: (IsSettings o, MonadIO m) => SettingsSchema -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “settings-schema” property. This is rarely needed directly, but it is used by new.

getSettingsSettingsSchema :: (MonadIO m, IsSettings o) => o -> m (Maybe SettingsSchema)

Get the value of the “settings-schema” property. When overloading is enabled, this is equivalent to

get settings #settingsSchema

Signals

changeEvent

type C_SettingsChangeEventCallback = Ptr () -> Ptr Word32 -> Int32 -> Ptr () -> IO CInt

Type for the callback on the (unwrapped) C side.

type SettingsChangeEventCallback

Arguments

 = Maybe [Word32]

keys: an array of GQuarks for the changed keys, or Nothing

-> IO Bool

Returns: True to stop other handlers from being invoked for the event. FALSE to propagate the event further.

The "change-event" signal is emitted once per change event that affects this settings object. You should connect to this signal only if you are interested in viewing groups of changes before they are split out into multiple emissions of the "changed" signal. For most use cases it is more appropriate to use the "changed" signal.

In the event that the change event applies to one or more specified keys, keys will be an array of GQuark of length nKeys. In the event that the change event applies to the Settings object as a whole (ie: potentially every key has been changed) then keys will be Nothing and nKeys will be 0.

The default handler for this signal invokes the "changed" signal for each affected key. If any other connected handler returns True then this default functionality will be suppressed.

afterSettingsChangeEvent :: (IsSettings a, MonadIO m) => a -> SettingsChangeEventCallback -> m SignalHandlerId

Connect a signal handler for the changeEvent signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after settings #changeEvent callback

genClosure_SettingsChangeEvent :: MonadIO m => SettingsChangeEventCallback -> m (GClosure C_SettingsChangeEventCallback)

Wrap the callback into a GClosure.

mk_SettingsChangeEventCallback :: C_SettingsChangeEventCallback -> IO (FunPtr C_SettingsChangeEventCallback)

Generate a function pointer callable from C code, from a C_SettingsChangeEventCallback.

noSettingsChangeEventCallback :: Maybe SettingsChangeEventCallback

A convenience synonym for Nothing :: Maybe SettingsChangeEventCallback.

onSettingsChangeEvent :: (IsSettings a, MonadIO m) => a -> SettingsChangeEventCallback -> m SignalHandlerId

Connect a signal handler for the changeEvent signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on settings #changeEvent callback

wrap_SettingsChangeEventCallback :: SettingsChangeEventCallback -> C_SettingsChangeEventCallback

Wrap a SettingsChangeEventCallback into a C_SettingsChangeEventCallback.

changed

type C_SettingsChangedCallback = Ptr () -> CString -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type SettingsChangedCallback

Arguments

 = Text

key: the name of the key that changed

-> IO ()

The "changed" signal is emitted when a key has potentially changed. You should call one of the g_settings_get() calls to check the new value.

This signal supports detailed connections. You can connect to the detailed signal "changed[x](#signal:x)" in order to only receive callbacks when key "x" changes.

Note that settings only emits this signal if you have read key at least once while a signal handler was already connected for key.

afterSettingsChanged :: (IsSettings a, MonadIO m) => a -> Maybe Text -> SettingsChangedCallback -> m SignalHandlerId

Connect a signal handler for the changed signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after settings #changed callback

This signal admits a optional parameter detail. If it's not Nothing, we will connect to “changed::detail” instead.

genClosure_SettingsChanged :: MonadIO m => SettingsChangedCallback -> m (GClosure C_SettingsChangedCallback)

Wrap the callback into a GClosure.

mk_SettingsChangedCallback :: C_SettingsChangedCallback -> IO (FunPtr C_SettingsChangedCallback)

Generate a function pointer callable from C code, from a C_SettingsChangedCallback.

noSettingsChangedCallback :: Maybe SettingsChangedCallback

A convenience synonym for Nothing :: Maybe SettingsChangedCallback.

onSettingsChanged :: (IsSettings a, MonadIO m) => a -> Maybe Text -> SettingsChangedCallback -> m SignalHandlerId

Connect a signal handler for the changed signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on settings #changed callback

This signal admits a optional parameter detail. If it's not Nothing, we will connect to “changed::detail” instead.

wrap_SettingsChangedCallback :: SettingsChangedCallback -> C_SettingsChangedCallback

Wrap a SettingsChangedCallback into a C_SettingsChangedCallback.

writableChangeEvent

type C_SettingsWritableChangeEventCallback = Ptr () -> Word32 -> Ptr () -> IO CInt

Type for the callback on the (unwrapped) C side.

type SettingsWritableChangeEventCallback

Arguments

 = Word32

key: the quark of the key, or 0

-> IO Bool

Returns: True to stop other handlers from being invoked for the event. FALSE to propagate the event further.

The "writable-change-event" signal is emitted once per writability change event that affects this settings object. You should connect to this signal if you are interested in viewing groups of changes before they are split out into multiple emissions of the "writable-changed" signal. For most use cases it is more appropriate to use the "writable-changed" signal.

In the event that the writability change applies only to a single key, key will be set to the GQuark for that key. In the event that the writability change affects the entire settings object, key will be 0.

The default handler for this signal invokes the "writable-changed" and "changed" signals for each affected key. This is done because changes in writability might also imply changes in value (if for example, a new mandatory setting is introduced). If any other connected handler returns True then this default functionality will be suppressed.

afterSettingsWritableChangeEvent :: (IsSettings a, MonadIO m) => a -> SettingsWritableChangeEventCallback -> m SignalHandlerId

Connect a signal handler for the writableChangeEvent signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after settings #writableChangeEvent callback

genClosure_SettingsWritableChangeEvent :: MonadIO m => SettingsWritableChangeEventCallback -> m (GClosure C_SettingsWritableChangeEventCallback)

Wrap the callback into a GClosure.

mk_SettingsWritableChangeEventCallback :: C_SettingsWritableChangeEventCallback -> IO (FunPtr C_SettingsWritableChangeEventCallback)

Generate a function pointer callable from C code, from a C_SettingsWritableChangeEventCallback.

noSettingsWritableChangeEventCallback :: Maybe SettingsWritableChangeEventCallback

A convenience synonym for Nothing :: Maybe SettingsWritableChangeEventCallback.

onSettingsWritableChangeEvent :: (IsSettings a, MonadIO m) => a -> SettingsWritableChangeEventCallback -> m SignalHandlerId

Connect a signal handler for the writableChangeEvent signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on settings #writableChangeEvent callback

wrap_SettingsWritableChangeEventCallback :: SettingsWritableChangeEventCallback -> C_SettingsWritableChangeEventCallback

Wrap a SettingsWritableChangeEventCallback into a C_SettingsWritableChangeEventCallback.

writableChanged

type C_SettingsWritableChangedCallback = Ptr () -> CString -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type SettingsWritableChangedCallback

Arguments

 = Text

key: the key

-> IO ()

The "writable-changed" signal is emitted when the writability of a key has potentially changed. You should call settingsIsWritable in order to determine the new status.

This signal supports detailed connections. You can connect to the detailed signal "writable-changed[x](#signal:x)" in order to only receive callbacks when the writability of "x" changes.

afterSettingsWritableChanged :: (IsSettings a, MonadIO m) => a -> Maybe Text -> SettingsWritableChangedCallback -> m SignalHandlerId

Connect a signal handler for the writableChanged signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after settings #writableChanged callback

This signal admits a optional parameter detail. If it's not Nothing, we will connect to “writable-changed::detail” instead.

genClosure_SettingsWritableChanged :: MonadIO m => SettingsWritableChangedCallback -> m (GClosure C_SettingsWritableChangedCallback)

Wrap the callback into a GClosure.

mk_SettingsWritableChangedCallback :: C_SettingsWritableChangedCallback -> IO (FunPtr C_SettingsWritableChangedCallback)

Generate a function pointer callable from C code, from a C_SettingsWritableChangedCallback.

noSettingsWritableChangedCallback :: Maybe SettingsWritableChangedCallback

A convenience synonym for Nothing :: Maybe SettingsWritableChangedCallback.

onSettingsWritableChanged :: (IsSettings a, MonadIO m) => a -> Maybe Text -> SettingsWritableChangedCallback -> m SignalHandlerId

Connect a signal handler for the writableChanged signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on settings #writableChanged callback

This signal admits a optional parameter detail. If it's not Nothing, we will connect to “writable-changed::detail” instead.

wrap_SettingsWritableChangedCallback :: SettingsWritableChangedCallback -> C_SettingsWritableChangedCallback

Wrap a SettingsWritableChangedCallback into a C_SettingsWritableChangedCallback.