Gio.Initable¶

Implementations:: Gio.CharsetConverter, Gio.DBusConnection, Gio.DBusObjectManagerClient, Gio.DBusProxy, Gio.DBusServer, Gio.DebugControllerDBus, Gio.InetAddressMask, Gio.Socket, Gio.Subprocess

Methods¶

class	`newv` (object_type, parameters, cancellable)
	`init` (cancellable)

Virtual Methods¶

do_init (cancellable)

Properties¶

None

Signals¶

None

Fields¶

None

Class Details¶

class Gio.Initable¶

Bases:: GObject.GInterface
Structure:: Gio.InitableIface

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 [method`Gio`.Initable.init] or [method`Gio`.AsyncInitable.init_async] (the latter is only available if it also implements [iface`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 [func`GLib`.critical] or [func`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 [func`Gio`.Initable.new] directly, or indirectly via a foo_thing_new() wrapper. This will call [method`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.

New in version 2.22.

classmethod newv(object_type, parameters, cancellable)[source]¶

Parameters:

object_type (GObject.GType) – a GObject.GType supporting Gio.Initable.
parameters ([GObject.Parameter]) – the parameters to use to construct the object
cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.

Raises:

GLib.Error

Returns:

a newly allocated GObject.Object, or None on error

Return type:

GObject.Object

Helper function for constructing Gio.Initable object. This is similar to GObject.Object.newv() but also initializes the object and returns None, setting an error on failure.

New in version 2.22.

Deprecated since version 2.54: Use g_object_new_with_properties() and Gio.Initable.init() instead. See GObject.Parameter for more information.

init(cancellable)[source]¶

Parameters:: cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.
Raises:: GLib.Error
Returns:: True if successful. If an error has occurred, this function will return False and set error appropriately if present.
Return type:: bool

Initializes the object implementing the interface.

This method is intended for language bindings. If writing in C, g_initable_new() should typically be used instead.

The object must be initialized before any real use after initial construction, either with this function or Gio.AsyncInitable.init_async().

Implementations may also support cancellation. If cancellable is not None, then initialization can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED will be returned. If cancellable is not None and the object doesn’t support cancellable initialization the error 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 GObject.Object.ref() and 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 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 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 GObject.ObjectClass.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call Gio.Initable.init() on the result of g_object_new(), regardless of whether it is in fact a new instance.

New in version 2.22.

do_init(cancellable) virtual¶

Parameters:: cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.
Returns:: True if successful. If an error has occurred, this function will return False and set error appropriately if present.
Return type:: bool

Initializes the object implementing the interface.

This method is intended for language bindings. If writing in C, g_initable_new() should typically be used instead.

The object must be initialized before any real use after initial construction, either with this function or Gio.AsyncInitable.init_async().

Implementations may also support cancellation. If cancellable is not None, then initialization can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED will be returned. If cancellable is not None and the object doesn’t support cancellable initialization the error 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 GObject.Object.ref() and 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 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 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 GObject.ObjectClass.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call Gio.Initable.init() on the result of g_object_new(), regardless of whether it is in fact a new instance.

New in version 2.22.