GObject.ParamSpec

Subclasses:

GObject.ParamSpecBoolean, GObject.ParamSpecBoxed, GObject.ParamSpecChar, GObject.ParamSpecDouble, GObject.ParamSpecEnum, GObject.ParamSpecFlags, GObject.ParamSpecFloat, GObject.ParamSpecGType, GObject.ParamSpecInt, GObject.ParamSpecInt64, GObject.ParamSpecLong, GObject.ParamSpecObject, GObject.ParamSpecOverride, GObject.ParamSpecParam, GObject.ParamSpecPointer, GObject.ParamSpecString, GObject.ParamSpecUChar, GObject.ParamSpecUInt, GObject.ParamSpecUInt64, GObject.ParamSpecULong, GObject.ParamSpecUnichar, GObject.ParamSpecValueArray, GObject.ParamSpecVariant

Methods

class	is_valid_name (name)
	get_blurb ()
	get_default_value ()
	get_name ()
	get_name_quark ()
	get_nick ()
	get_qdata (quark)
	get_redirect_target ()
	set_qdata (quark, data)
	sink ()
	steal_qdata (quark)

Virtual Methods

	do_finalize ()
	do_value_is_valid (value)
	do_value_set_default (value)
	do_value_validate (value)
	do_values_cmp (value1, value2)

Fields

Name	Type	Access	Description
flags	GObject.ParamFlags	r	GParamFlags flags for this parameter
g_type_instance	GObject.TypeInstance	r	private GTypeInstance portion
name	str	r	name of this parameter: always an interned string
owner_type	GObject.GType	r	GType type that uses (introduces) this parameter
param_id	int	r
qdata	GLib.Data	r
ref_count	int	r
value_type	GObject.GType	r	the GValue type for this parameter

Class Details

class GObject.ParamSpec

Abstract:

Yes

Structure:

GObject.ParamSpecClass

GParamSpec encapsulates the metadata required to specify parameters, such as GObject properties.

Parameter names

A property name consists of one or more segments consisting of ASCII letters and digits, separated by either the - or _ character. The first character of a property name must be a letter. These are the same rules as for signal naming (see [func`GObject`.signal_new]).

When creating and looking up a GParamSpec, either separator can be used, but they cannot be mixed. Using - is considerably more efficient, and is the ‘canonical form’. Using _ is discouraged.

classmethod is_valid_name(name)

Parameters:

name (str) – the canonical name of the property

Returns:

True if name is a valid property name, False otherwise.

Return type:

bool

Validate a property name for a GObject.ParamSpec. This can be useful for dynamically-generated properties which need to be validated at run-time before actually trying to create them.

See canonical parameter names for details of the rules for valid names.

New in version 2.66.

get_blurb()

Returns:

the short description of self.

Return type:

str or None

Get the short description of a GObject.ParamSpec.

get_default_value()

Returns:

a pointer to a GObject.Value which must not be modified

Return type:

GObject.Value

Gets the default value of self as a pointer to a GObject.Value.

The GObject.Value will remain valid for the life of self.

New in version 2.38.

get_name()

Returns:

the name of self.

Return type:

str

Get the name of a GObject.ParamSpec.

The name is always an “interned” string (as per GLib.intern_string()). This allows for pointer-value comparisons.

get_name_quark()

Returns:

the GQuark for self->name.

Return type:

int

Gets the GQuark for the name.

New in version 2.46.

get_nick()

Returns:

the nickname of self.

Return type:

str

Get the nickname of a GObject.ParamSpec.

get_qdata(quark)

Parameters:

quark (int) – a #GQuark, naming the user data pointer

Returns:

the user data pointer set, or None

Return type:

object or None

Gets back user data pointers stored via GObject.ParamSpec.set_qdata().

get_redirect_target()

Returns:

paramspec to which requests on this paramspec should be redirected, or None if none.

Return type:

GObject.ParamSpec or None

If the paramspec redirects operations to another paramspec, returns that paramspec. Redirect is used typically for providing a new implementation of a property in a derived type while preserving all the properties from the parent type. Redirection is established by creating a property of type GObject.ParamSpecOverride. See GObject.ObjectClass.override_property() for an example of the use of this capability.

New in version 2.4.

set_qdata(quark, data)

Parameters:

• quark (int) – a #GQuark, naming the user data pointer

• data (object or None) – an opaque user data pointer

Sets an opaque, named pointer on a GObject.ParamSpec. The name is specified through a #GQuark (retrieved e.g. via GLib.quark_from_static_string()), and the pointer can be gotten back from the self with GObject.ParamSpec.get_qdata(). Setting a previously set user data pointer, overrides (frees) the old pointer set, using None as pointer essentially removes the data stored.

sink()

The initial reference count of a newly created GObject.ParamSpec is 1, even though no one has explicitly called g_param_spec_ref() on it yet. So the initial reference count is flagged as “floating”, until someone calls g_param_spec_ref (pspec); g_param_spec_sink (pspec); in sequence on it, taking over the initial reference count (thus ending up with a self that has a reference count of 1 still, but is not flagged “floating” anymore).

steal_qdata(quark)

Parameters:

quark (int) – a #GQuark, naming the user data pointer

Returns:

the user data pointer set, or None

Return type:

object or None

Gets back user data pointers stored via GObject.ParamSpec.set_qdata() and removes the data from self without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier.

do_finalize() virtual

The instance finalization function (optional), should chain up to the finalize method of the parent class.

do_value_is_valid(value) virtual

Parameters:

value (GObject.Value) –

Return type:

bool

Checks if contents of value comply with the specifications set out by this type, without modifying the value. This vfunc is optional. If it isn’t set, GObject.Object will use value_validate.

New in version 2.74.

do_value_set_default(value) virtual

Parameters:

value (GObject.Value) –

Resets a value to the default value for this type (recommended, the default is GObject.Value.reset()), see GObject.param_value_set_default().

do_value_validate(value) virtual

Parameters:

value (GObject.Value) –

Return type:

bool

Ensures that the contents of value comply with the specifications set out by this type (optional), see GObject.param_value_validate().

do_values_cmp(value1, value2) virtual

Parameters:

• value1 (GObject.Value) –

• value2 (GObject.Value) –

Return type:

int

Compares value1 with value2 according to this type (recommended, the default is memcmp()), see GObject.param_values_cmp().