:right-sidebar: True Initable =================================================================== .. currentmodule:: gi.repository.Gio .. versionadded:: 2.22 .. class:: Initable(*args, **kwargs) :no-contents-entry: Implementations: :class:`~gi.repository.Gio.CharsetConverter`, :class:`~gi.repository.Gio.DBusConnection`, :class:`~gi.repository.Gio.DBusObjectManagerClient`, :class:`~gi.repository.Gio.DBusProxy`, :class:`~gi.repository.Gio.DBusServer`, :class:`~gi.repository.Gio.DebugControllerDBus`, :class:`~gi.repository.Gio.InetAddressMask`, :class:`~gi.repository.Gio.Socket`, :class:`~gi.repository.Gio.Subprocess` ``GInitable`` is implemented by objects that can fail during initialization. If an object implements this interface then it must be initialized as the first thing after construction, either via :obj:`~gi.repository.Gio.Initable.init` or :obj:`~gi.repository.Gio.AsyncInitable.init_async` (the latter is only available if it also implements :obj:`~gi.repository.Gio.AsyncInitable`\). If the object is not initialized, or initialization returns with an error, then all operations on the object except ``g_object_ref()`` and ``g_object_unref()`` are considered to be invalid, and have undefined behaviour. They will often fail with :obj:`~gi.repository.GLib.critical` or :obj:`~gi.repository.GLib.warning`\, but this must not be relied on. Users of objects implementing this are not intended to use the interface method directly, instead it will be used automatically in various ways. For C applications you generally just call :obj:`~gi.repository.Gio.Initable.new` directly, or indirectly via a ``foo_thing_new()`` wrapper. This will call :obj:`~gi.repository.Gio.Initable.init` under the cover, returning ``NULL`` and setting a ``GError`` on failure (at which point the instance is unreferenced). For bindings in languages where the native constructor supports exceptions the binding could check for objects implementing ``GInitable`` during normal construction and automatically initialize them, throwing an exception on failure. Methods ------- .. rst-class:: interim-class .. class:: Initable :no-index: .. method:: init(cancellable: ~gi.repository.Gio.Cancellable | None = None) -> bool Initializes the object implementing the interface. This method is intended for language bindings. If writing in C, :func:`~gi.repository.Gio.Initable.new` should typically be used instead. The object must be initialized before any real use after initial construction, either with this function or :func:`~gi.repository.Gio.AsyncInitable.init_async`. Implementations may also support cancellation. If ``cancellable`` is not :const:`None`, then initialization can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error :const:`~gi.repository.Gio.IOErrorEnum.CANCELLED` will be returned. If ``cancellable`` is not :const:`None` and the object doesn't support cancellable initialization the error :const:`~gi.repository.Gio.IOErrorEnum.NOT_SUPPORTED` will be returned. If the object is not initialized, or initialization returns with an error, then all operations on the object except :func:`~gi.repository.GObject.GObject.Object.ref` and :func:`~gi.repository.GObject.GObject.Object.unref` are considered to be invalid, and have undefined behaviour. See the [introduction][ginitable] for more details. Callers should not assume that a class which implements :obj:`~gi.repository.Gio.Initable` can be initialized multiple times, unless the class explicitly documents itself as supporting this. Generally, a class’ implementation of init() can assume (and assert) that it will only be called once. Previously, this documentation recommended all :obj:`~gi.repository.Gio.Initable` implementations should be idempotent; that recommendation was relaxed in GLib 2.54. If a class explicitly supports being initialized multiple times, it is recommended that the method is idempotent: multiple calls with the same arguments should return the same results. Only the first call initializes the object; further calls return the result of the first call. One reason why a class might need to support idempotent initialization is if it is designed to be used via the singleton pattern, with a :obj:`~gi.repository.GObject.ObjectClass`\.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call :func:`~gi.repository.Gio.Initable.init` on the result of :func:`~gi.repository.GObject.GObject.Object.new`, regardless of whether it is in fact a new instance. .. versionadded:: 2.22 :param cancellable: optional :obj:`~gi.repository.Gio.Cancellable` object, :const:`None` to ignore. .. classmethod:: newv(parameters: list[~gi.repository.GObject.Parameter], cancellable: ~gi.repository.Gio.Cancellable | None = None) -> ~gi.repository.GObject.Object Helper function for constructing :obj:`~gi.repository.Gio.Initable` object. This is similar to :func:`~gi.repository.GObject.GObject.Object.newv` but also initializes the object and returns :const:`None`, setting an error on failure. .. versionadded:: 2.22 .. deprecated:: 2.54 Use :func:`~gi.repository.GObject.GObject.Object.new_with_properties` and :func:`~gi.repository.Gio.Initable.init` instead. See :obj:`~gi.repository.GObject.Parameter` for more information. :param parameters: the parameters to use to construct the object :param cancellable: optional :obj:`~gi.repository.Gio.Cancellable` object, :const:`None` to ignore. Virtual Methods --------------- .. rst-class:: interim-class .. class:: Initable :no-index: .. method:: do_init(cancellable: ~gi.repository.Gio.Cancellable | None = None) -> bool Initializes the object implementing the interface. This method is intended for language bindings. If writing in C, :func:`~gi.repository.Gio.Initable.new` should typically be used instead. The object must be initialized before any real use after initial construction, either with this function or :func:`~gi.repository.Gio.AsyncInitable.init_async`. Implementations may also support cancellation. If ``cancellable`` is not :const:`None`, then initialization can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error :const:`~gi.repository.Gio.IOErrorEnum.CANCELLED` will be returned. If ``cancellable`` is not :const:`None` and the object doesn't support cancellable initialization the error :const:`~gi.repository.Gio.IOErrorEnum.NOT_SUPPORTED` will be returned. If the object is not initialized, or initialization returns with an error, then all operations on the object except :func:`~gi.repository.GObject.GObject.Object.ref` and :func:`~gi.repository.GObject.GObject.Object.unref` are considered to be invalid, and have undefined behaviour. See the [introduction][ginitable] for more details. Callers should not assume that a class which implements :obj:`~gi.repository.Gio.Initable` can be initialized multiple times, unless the class explicitly documents itself as supporting this. Generally, a class’ implementation of init() can assume (and assert) that it will only be called once. Previously, this documentation recommended all :obj:`~gi.repository.Gio.Initable` implementations should be idempotent; that recommendation was relaxed in GLib 2.54. If a class explicitly supports being initialized multiple times, it is recommended that the method is idempotent: multiple calls with the same arguments should return the same results. Only the first call initializes the object; further calls return the result of the first call. One reason why a class might need to support idempotent initialization is if it is designed to be used via the singleton pattern, with a :obj:`~gi.repository.GObject.ObjectClass`\.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call :func:`~gi.repository.Gio.Initable.init` on the result of :func:`~gi.repository.GObject.GObject.Object.new`, regardless of whether it is in fact a new instance. .. versionadded:: 2.22 :param cancellable: optional :obj:`~gi.repository.Gio.Cancellable` object, :const:`None` to ignore.