ParamSpec

class ParamSpec(*args, **kwargs)

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

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 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.

Methods

class ParamSpec

get_blurb() → str | None

Get the short description of a ParamSpec.

get_default_value() → Any

Gets the default value of pspec as a pointer to a Value.

The Value will remain valid for the life of pspec.

Added in version 2.38.

get_name() → str

Get the name of a ParamSpec.

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

get_name_quark() → int

Gets the GQuark for the name.

Added in version 2.46.

get_nick() → str

Get the nickname of a ParamSpec.

get_qdata(quark: int) → None

Gets back user data pointers stored via set_qdata().

Parameters:

quark – a Quark, naming the user data pointer

get_redirect_target() → ParamSpec | 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 GParamSpecOverride. See override_property() for an example of the use of this capability.

Added in version 2.4.

is_valid_name(name: str) → bool

Validate a property name for a 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][canonical-parameter-names] for details of the rules for valid names.

Added in version 2.66.

Parameters:

name – the canonical name of the property

set_qdata(quark: int, data: None) → None

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

Parameters:

• quark – a Quark, naming the user data pointer

• data – an opaque user data pointer

sink() → None

The initial reference count of a newly created ParamSpec is 1, even though no one has explicitly called 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 pspec that has a reference count of 1 still, but is not flagged “floating” anymore).

Virtual Methods

class ParamSpec

do_finalize() → None

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

do_value_is_valid(value: Any) → 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 will use value_validate. Since 2.74

Parameters:

value

do_value_set_default(value: Any) → None

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

Parameters:

value

do_value_validate(value: Any) → bool

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

Parameters:

value

do_values_cmp(value1: Any, value2: Any) → int

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

Parameters:

• value1

• value2

Fields

class ParamSpec

flags

GParamFlags flags for this parameter

g_type_instance

Private GTypeInstance portion

name

Name of this parameter: always an interned string

owner_type

GType type that uses (introduces) this parameter

param_id

qdata

ref_count

value_type

The GValue type for this parameter