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Functions
Properties
GSettingsBackend * | backend | Read / Write / Construct Only |
gboolean | delay-apply | Read |
gboolean | has-unapplied | Read |
gchar * | path | Read / Write / Construct Only |
gchar * | schema | Read / Write / Construct Only |
gchar * | schema-id | Read / Write / Construct Only |
GSettingsSchema * | settings-schema | Read / Write / Construct Only |
Description
The GSettings class provides a convenient API for storing and retrieving application settings.
Reads and writes can be considered to be non-blocking. Reading
settings with GSettings is typically extremely fast: on
approximately the same order of magnitude (but slower than) a
GHashTable 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 GSettings 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 g_settings_bind()
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', 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 GVariantType 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
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:
1 2 3 4 |
<!-- 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.php --> <default 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 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 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. The underlying type of such a key
is string, but you can use g_settings_get_enum()
, g_settings_set_enum()
,
g_settings_get_flags()
, g_settings_set_flags()
access the numeric values
corresponding to the string value of enum and flags keys.
An example for default value:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
<schemalist> <schema id="org.gtk.Test" path="/org/gtk/Test/" gettext-domain="test"> <key name="greeting" type="s"> <default l10n="messages">"Hello, earthlings"</default> <summary>A greeting</summary> <description> Greeting of the invading martians </description> </key> <key name="box" type="(ii)"> <default>(20,30)</default> </key> </schema> </schemalist> |
An example for ranges, choices and enumerated types:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 |
<schemalist> <enum id="org.gtk.Test.myenum"> <value nick="first" value="1"/> <value nick="second" value="2"/> </enum> <flags id="org.gtk.Test.myflags"> <value nick="flag1" value="1"/> <value nick="flag2" value="2"/> <value nick="flag3" value="4"/> </flags> <schema id="org.gtk.Test"> <key name="key-with-range" type="i"> <range min="1" max="100"/> <default>10</default> </key> <key name="key-with-choices" type="s"> <choices> <choice value='Elisabeth'/> <choice value='Annabeth'/> <choice value='Joe'/> </choices> <aliases> <alias value='Anna' target='Annabeth'/> <alias value='Beth' target='Elisabeth'/> </aliases> <default>'Joe'</default> </key> <key name='enumerated-key' enum='org.gtk.Test.myenum'> <default>'first'</default> </key> <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 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:
1 2 3 |
[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 GObject properties
directly to settings, using g_settings_bind()
. 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.
Relocatable schemas
A relocatable schema is one with no path
attribute specified on its
<schema> element. By using g_settings_new_with_path()
, a GSettings object
can be instantiated for a relocatable schema, assigning a path to the
instance. Paths passed to g_settings_new_with_path()
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.:
1 2 3 |
<schema id="org.foo.MyApp" path="/org/foo/MyApp/"> <child name="main" schema="org.foo.MyApp.Window"/> </schema> |
Build system integration
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
:
1 |
GLIB_GSETTINGS |
In the appropriate Makefile.am
, use the following snippet to compile and
install the named schema:
1 2 3 4 |
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):
1 |
data/org.foo.MyApp.gschema.xml |
Alternatively, if intltool 0.50.1 is in use:
1 |
[type: gettext/gsettings]data/org.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
:
1 2 |
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
.
Functions
g_settings_new ()
GSettings *
g_settings_new (const gchar *schema_id
);
Creates a new GSettings object with the schema specified by
schema_id
.
Signals on the newly created GSettings object will be dispatched
via the thread-default GMainContext in effect at the time of the
call to g_settings_new()
. The new GSettings will hold a reference
on the context. See g_main_context_push_thread_default()
.
Since: 2.26
g_settings_new_with_path ()
GSettings * g_settings_new_with_path (const gchar *schema_id
,const gchar *path
);
Creates a new GSettings object with the relocatable schema specified
by schema_id
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
g_settings_new_with_backend ()
GSettings * g_settings_new_with_backend (const gchar *schema_id
,GSettingsBackend *backend
);
Creates a new GSettings object with the schema specified by
schema_id
and a given GSettingsBackend.
Creating a GSettings 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
g_settings_new_with_backend_and_path ()
GSettings * g_settings_new_with_backend_and_path (const gchar *schema_id
,GSettingsBackend *backend
,const gchar *path
);
Creates a new GSettings object with the schema specified by
schema_id
and a given GSettingsBackend and path.
This is a mix of g_settings_new_with_backend()
and
g_settings_new_with_path()
.
Since: 2.26
g_settings_new_full ()
GSettings * g_settings_new_full (GSettingsSchema *schema
,GSettingsBackend *backend
,const gchar *path
);
Creates a new GSettings 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 GSettings object is a pure composition of 4 things: a GSettingsSchema, a GSettingsBackend, a path within that backend, and a GMainContext to which signals are dispatched.
This constructor therefore gives you full control over constructing
GSettings 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 g_settings_new()
).
If backend
is NULL
then the default backend is used.
If path
is NULL
then the path from the schema is used. It is an
error if path
is NULL
and the schema has no path of its own or if
path
is non-NULL
and not equal to the path that the schema does
have.
Since: 2.32
g_settings_sync ()
void
g_settings_sync (void
);
Ensures that all pending operations are complete for the default backend.
Writes made to a GSettings 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).
g_settings_get_value ()
GVariant * g_settings_get_value (GSettings *settings
,const gchar *key
);
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
g_settings_set_value ()
gboolean g_settings_set_value (GSettings *settings
,const gchar *key
,GVariant *value
);
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
g_settings_is_writable ()
gboolean g_settings_is_writable (GSettings *settings
,const gchar *name
);
Finds out if a key can be written or not
Since: 2.26
g_settings_delay ()
void
g_settings_delay (GSettings *settings
);
Changes the GSettings object into 'delay-apply' mode. In this
mode, changes to settings
are not immediately propagated to the
backend, but kept locally until g_settings_apply()
is called.
Since: 2.26
g_settings_apply ()
void
g_settings_apply (GSettings *settings
);
Applies any changes that have been made to the settings. This
function does nothing unless settings
is in 'delay-apply' mode;
see g_settings_delay()
. In the normal case settings are always
applied immediately.
g_settings_revert ()
void
g_settings_revert (GSettings *settings
);
Reverts all non-applied changes to the settings. This function
does nothing unless settings
is in 'delay-apply' mode; see
g_settings_delay()
. In the normal case settings are always applied
immediately.
Change notifications will be emitted for affected keys.
g_settings_get_has_unapplied ()
gboolean
g_settings_get_has_unapplied (GSettings *settings
);
Returns whether the GSettings object has any unapplied changes. This can only be the case if it is in 'delayed-apply' mode.
Since: 2.26
g_settings_get_child ()
GSettings * g_settings_get_child (GSettings *settings
,const gchar *name
);
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
g_settings_reset ()
void g_settings_reset (GSettings *settings
,const gchar *key
);
Resets key
to its default value.
This call resets the key, as much as possible, to its default value. That might the value specified in the schema or the one set by the administrator.
g_settings_get_user_value ()
GVariant * g_settings_get_user_value (GSettings *settings
,const gchar *key
);
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 g_settings_reset()
this function should always return
NULL
(assuming something is not wrong with the system
configuration).
It is possible that g_settings_get_value()
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
g_settings_get_default_value ()
GVariant * g_settings_get_default_value (GSettings *settings
,const gchar *key
);
Gets the "default value" of a key.
This is the value that would be read if g_settings_reset()
were to be
called on the key.
Note that this may be a different value than returned by
g_settings_schema_key_get_default_value()
if the system administrator
has provided a default value.
Comparing the return values of g_settings_get_default_value()
and
g_settings_get_value()
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
g_settings_list_schemas ()
const gchar * const *
g_settings_list_schemas (void
);
g_settings_list_schemas
has been deprecated since version 2.40 and should not be used in newly-written code.
Use g_settings_schema_source_list_schemas()
instead.
If you used g_settings_list_schemas()
to check for the presence of
a particular schema, use g_settings_schema_source_lookup()
instead
of your whole loop.
Deprecated.
Returns
a list of GSettings schemas that are available. The list must not be modified or freed.
[element-type utf8][transfer none]
Since: 2.26
g_settings_list_relocatable_schemas ()
const gchar * const *
g_settings_list_relocatable_schemas (void
);
g_settings_list_relocatable_schemas
has been deprecated since version 2.40 and should not be used in newly-written code.
Use g_settings_schema_source_list_schemas()
instead
Deprecated.
Returns
a list of relocatable GSettings schemas that are available. The list must not be modified or freed.
[element-type utf8][transfer none]
Since: 2.28
g_settings_list_keys ()
gchar **
g_settings_list_keys (GSettings *settings
);
g_settings_list_keys
is deprecated and should not be used in newly-written code.
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 g_strfreev()
when you are done
with it.
g_settings_list_children ()
gchar **
g_settings_list_children (GSettings *settings
);
Gets the list of children on settings
.
The list is exactly the list of strings for which it is not an error
to call g_settings_get_child()
.
For GSettings objects that are lists, this value can change at any
time and you should connect to the "children-changed" signal to watch
for those changes. Note that there is a race condition here: you may
request a child after listing it only for it to have been destroyed
in the meantime. For this reason, g_settings_get_child()
may return
NULL
even for a child that was listed by this function.
For GSettings objects that are not lists, you should probably not be calling 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 g_strfreev()
when you are done
with it.
g_settings_get_range ()
GVariant * g_settings_get_range (GSettings *settings
,const gchar *key
);
g_settings_get_range
has been deprecated since version 2.40 and should not be used in newly-written code.
Use g_settings_schema_key_get_range()
instead.
Queries the range of a key.
Since: 2.28
g_settings_range_check ()
gboolean g_settings_range_check (GSettings *settings
,const gchar *key
,GVariant *value
);
g_settings_range_check
has been deprecated since version 2.40 and should not be used in newly-written code.
Use g_settings_schema_key_range_check()
instead.
Checks if the given value
is of the correct type and within the
permitted range for key
.
Since: 2.28
g_settings_get ()
void g_settings_get (GSettings *settings
,const gchar *key
,const gchar *format
,...
);
Gets the value that is stored at key
in settings
.
A convenience function that combines g_settings_get_value()
with
g_variant_get()
.
It is a programmer error to give a key
that isn't contained in the
schema for settings
or for the GVariantType of format
to mismatch
the type given in the schema.
Since: 2.26
g_settings_set ()
gboolean g_settings_set (GSettings *settings
,const gchar *key
,const gchar *format
,...
);
Sets key
in settings
to value
.
A convenience function that combines g_settings_set_value()
with
g_variant_new()
.
It is a programmer error to give a key
that isn't contained in the
schema for settings
or for the GVariantType of format
to mismatch
the type given in the schema.
Since: 2.26
g_settings_get_boolean ()
gboolean g_settings_get_boolean (GSettings *settings
,const gchar *key
);
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
g_settings_set_boolean ()
gboolean g_settings_set_boolean (GSettings *settings
,const gchar *key
,gboolean value
);
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
g_settings_get_int ()
gint g_settings_get_int (GSettings *settings
,const gchar *key
);
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
g_settings_set_int ()
gboolean g_settings_set_int (GSettings *settings
,const gchar *key
,gint value
);
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
g_settings_get_int64 ()
gint64 g_settings_get_int64 (GSettings *settings
,const gchar *key
);
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
g_settings_set_int64 ()
gboolean g_settings_set_int64 (GSettings *settings
,const gchar *key
,gint64 value
);
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
g_settings_get_uint ()
guint g_settings_get_uint (GSettings *settings
,const gchar *key
);
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
g_settings_set_uint ()
gboolean g_settings_set_uint (GSettings *settings
,const gchar *key
,guint value
);
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
g_settings_get_uint64 ()
guint64 g_settings_get_uint64 (GSettings *settings
,const gchar *key
);
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
g_settings_set_uint64 ()
gboolean g_settings_set_uint64 (GSettings *settings
,const gchar *key
,guint64 value
);
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
g_settings_get_double ()
gdouble g_settings_get_double (GSettings *settings
,const gchar *key
);
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
g_settings_set_double ()
gboolean g_settings_set_double (GSettings *settings
,const gchar *key
,gdouble value
);
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
g_settings_get_string ()
gchar * g_settings_get_string (GSettings *settings
,const gchar *key
);
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
g_settings_set_string ()
gboolean g_settings_set_string (GSettings *settings
,const gchar *key
,const gchar *value
);
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
g_settings_get_strv ()
gchar ** g_settings_get_strv (GSettings *settings
,const gchar *key
);
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
.
Returns
a
newly-allocated, NULL
-terminated array of strings, the value that
is stored at key
in settings
.
[array zero-terminated=1][transfer full]
Since: 2.26
g_settings_set_strv ()
gboolean g_settings_set_strv (GSettings *settings
,const gchar *key
,const gchar *const *value
);
Sets key
in settings
to value
.
A convenience variant of g_settings_set()
for string arrays. If
value
is NULL
, 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
g_settings_get_enum ()
gint g_settings_get_enum (GSettings *settings
,const gchar *key
);
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
g_settings_set_enum ()
gboolean g_settings_set_enum (GSettings *settings
,const gchar *key
,gint value
);
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
g_settings_get_string()
will return the 'nick' associated with
value
.
g_settings_get_flags ()
guint g_settings_get_flags (GSettings *settings
,const gchar *key
);
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
g_settings_set_flags ()
gboolean g_settings_set_flags (GSettings *settings
,const gchar *key
,guint value
);
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
g_settings_get_strv()
will return an array of 'nicks'; one for each
bit in value
.
GSettingsGetMapping ()
gboolean (*GSettingsGetMapping) (GVariant *value
,gpointer *result
,gpointer user_data
);
The type of the function that is used to convert from a value stored in a GSettings to a value that is useful to the application.
If the value is successfully mapped, the result should be stored at
result
and TRUE
returned. If mapping fails (for example, if value
is not in the right format) then FALSE
should be returned.
If value
is NULL
then it means that the mapping function is being
given a "last chance" to successfully return a valid value. TRUE
must be returned in this case.
Parameters
value |
||
result |
the result of the mapping. |
[out] |
user_data |
the user data that was passed to
|
[closure] |
g_settings_get_mapped ()
gpointer g_settings_get_mapped (GSettings *settings
,const gchar *key
,GSettingsGetMapping mapping
,gpointer user_data
);
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 NULL
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 NULL
. The same pointer is given
to each invocation of mapping
. The final value of that gpointer is
what is returned by this function. NULL
is valid; it is returned
just as any other value would be.
Parameters
settings |
a GSettings object |
|
key |
the key to get the value for |
|
mapping |
the function to map the value in the settings database to the value used by the application. |
[scope call] |
user_data |
user data for |
g_settings_bind ()
void g_settings_bind (GSettings *settings
,const gchar *key
,gpointer object
,const gchar *property
,GSettingsBindFlags flags
);
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 G_SETTINGS_BIND_NO_SENSITIVITY
, 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 g_settings_bind_writable()
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
g_settings_bind_with_mapping ()
void g_settings_bind_with_mapping (GSettings *settings
,const gchar *key
,gpointer object
,const gchar *property
,GSettingsBindFlags flags
,GSettingsBindGetMapping get_mapping
,GSettingsBindSetMapping set_mapping
,gpointer user_data
,GDestroyNotify destroy
);
Create a binding between the key
in the settings
object
and the property property
of object
.
The binding uses the provided mapping functions to map between settings and property values.
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.
[skip]
Parameters
settings |
a GSettings object |
|
key |
the key to bind |
|
object |
a GObject. |
[type GObject.Object] |
property |
the name of the property to bind |
|
flags |
flags for the binding |
|
get_mapping |
a function that gets called to convert values
from |
|
set_mapping |
a function that gets called to convert values
from |
|
user_data |
data that gets passed to |
|
destroy |
GDestroyNotify function for |
Since: 2.26
g_settings_bind_writable ()
void g_settings_bind_writable (GSettings *settings
,const gchar *key
,gpointer object
,const gchar *property
,gboolean inverted
);
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
g_settings_unbind ()
void g_settings_unbind (gpointer object
,const gchar *property
);
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
GSettingsBindSetMapping ()
GVariant * (*GSettingsBindSetMapping) (const GValue *value
,const GVariantType *expected_type
,gpointer user_data
);
The type for the function that is used to convert an object property value to a GVariant for storing it in GSettings.
Parameters
value |
a GValue containing the property value to map |
|
expected_type |
the GVariantType to create |
|
user_data |
user data that was specified when the binding was created |
GSettingsBindGetMapping ()
gboolean (*GSettingsBindGetMapping) (GValue *value
,GVariant *variant
,gpointer user_data
);
The type for the function that is used to convert from GSettings to
an object property. The value
is already initialized to hold values
of the appropriate type.
Parameters
value |
return location for the property value |
|
variant |
the GVariant |
|
user_data |
user data that was specified when the binding was created |
g_settings_create_action ()
GAction * g_settings_create_action (GSettings *settings
,const gchar *key
);
Creates a GAction corresponding to a given GSettings 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
Types and Values
GSettings
typedef struct _GSettings GSettings;
GSettings is an opaque data structure and can only be accessed using the following functions.
enum GSettingsBindFlags
Flags used when creating a binding. These flags determine in which direction the binding works. The default is to synchronize in both directions.
Members
Equivalent to |
||
Update the GObject property when the setting changes. It is an error to use this flag if the property is not writable. |
||
Update the setting when the GObject property changes. It is an error to use this flag if the property is not readable. |
||
Do not try to bind a "sensitivity" property to the writability of the setting |
||
When set in addition to G_SETTINGS_BIND_GET, set the GObject property value initially from the setting, but do not listen for changes of the setting |
||
When passed to |
Property Details
The “backend”
property
“backend” GSettingsBackend *
The name of the context that the settings are stored in.
Flags: Read / Write / Construct Only
The “delay-apply”
property
“delay-apply” gboolean
Whether the GSettings object is in 'delay-apply' mode. See
g_settings_delay()
for details.
Flags: Read
Default value: FALSE
Since: 2.28
The “has-unapplied”
property
“has-unapplied” gboolean
If this property is TRUE
, the GSettings object has outstanding
changes that will be applied when g_settings_apply()
is called.
Flags: Read
Default value: FALSE
The “path”
property
“path” gchar *
The path within the backend where the settings are stored.
Flags: Read / Write / Construct Only
Default value: NULL
The “schema”
property
“schema” gchar *
The name of the schema that describes the types of keys for this GSettings object.
The type of this property is *not* GSettingsSchema. GSettingsSchema 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 GSettingsSchema.
GSettings:schema
has been deprecated since version 2.32 and should not be used in newly-written code.
Use the 'schema-id' property instead. In a future version, this property may instead refer to a GSettingsSchema.
Flags: Read / Write / Construct Only
Default value: NULL
The “schema-id”
property
“schema-id” gchar *
The name of the schema that describes the types of keys for this GSettings object.
Flags: Read / Write / Construct Only
Default value: NULL
The “settings-schema”
property
“settings-schema” GSettingsSchema *
The GSettingsSchema describing the types of keys for this GSettings object.
Ideally, this property would be called 'schema'. GSettingsSchema 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.
Flags: Read / Write / Construct Only
Signal Details
The “change-event”
signal
gboolean user_function (GSettings *settings, gpointer keys, gint n_keys, gpointer user_data)
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 n_keys
. In the
event that the change event applies to the GSettings object as a
whole (ie: potentially every key has been changed) then keys
will
be NULL
and n_keys
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.
Returns
TRUE
to stop other handlers from being invoked for the
event. FALSE to propagate the event further.
Flags: Run Last
The “changed”
signal
void user_function (GSettings *settings, gchar *key, gpointer user_data)
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" 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
.
Parameters
settings |
the object on which the signal was emitted |
|
key |
the name of the key that changed |
|
user_data |
user data set when the signal handler was connected. |
Flags: Has Details
The “writable-change-event”
signal
gboolean user_function (GSettings *settings, guint key, gpointer user_data)
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.
Parameters
settings |
the object on which the signal was emitted |
|
key |
the quark of the key, or 0 |
|
user_data |
user data set when the signal handler was connected. |
Returns
TRUE
to stop other handlers from being invoked for the
event. FALSE to propagate the event further.
Flags: Run Last
The “writable-changed”
signal
void user_function (GSettings *settings, gchar *key, gpointer user_data)
The "writable-changed" signal is emitted when the writability of a
key has potentially changed. You should call
g_settings_is_writable()
in order to determine the new status.
This signal supports detailed connections. You can connect to the detailed signal "writable-changed::x" in order to only receive callbacks when the writability of "x" changes.
Parameters
settings |
the object on which the signal was emitted |
|
key |
the key |
|
user_data |
user data set when the signal handler was connected. |
Flags: Has Details