1 /* GObject - GLib Type, Object, Parameter and Signal Library
2 * Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General
15 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 #ifndef __G_OBJECT_H__
18 #define __G_OBJECT_H__
20 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
21 #error "Only <glib-object.h> can be included directly."
24 #include <gobject/gtype.h>
25 #include <gobject/gvalue.h>
26 #include <gobject/gparam.h>
27 #include <gobject/gclosure.h>
28 #include <gobject/gsignal.h>
29 #include <gobject/gboxed.h>
33 /* --- type macros --- */
36 * @type: Type id to check
38 * Check if the passed in type id is a %G_TYPE_OBJECT or derived from it.
40 * Returns: %FALSE or %TRUE, indicating whether @type is a %G_TYPE_OBJECT.
42 #define G_TYPE_IS_OBJECT(type) (G_TYPE_FUNDAMENTAL (type) == G_TYPE_OBJECT)
45 * @object: Object which is subject to casting.
47 * Casts a #GObject or derived pointer into a (GObject*) pointer.
48 * Depending on the current debugging level, this function may invoke
49 * certain runtime checks to identify invalid casts.
51 #define G_OBJECT(object) (G_TYPE_CHECK_INSTANCE_CAST ((object), G_TYPE_OBJECT, GObject))
54 * @class: a valid #GObjectClass
56 * Casts a derived #GObjectClass structure into a #GObjectClass structure.
58 #define G_OBJECT_CLASS(class) (G_TYPE_CHECK_CLASS_CAST ((class), G_TYPE_OBJECT, GObjectClass))
61 * @object: Instance to check for being a %G_TYPE_OBJECT.
63 * Checks whether a valid #GTypeInstance pointer is of type %G_TYPE_OBJECT.
65 #if GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_42
66 #define G_IS_OBJECT(object) (G_TYPE_CHECK_INSTANCE_FUNDAMENTAL_TYPE ((object), G_TYPE_OBJECT))
68 #define G_IS_OBJECT(object) (G_TYPE_CHECK_INSTANCE_TYPE ((object), G_TYPE_OBJECT))
72 * @class: a #GObjectClass
74 * Checks whether @class "is a" valid #GObjectClass structure of type
75 * %G_TYPE_OBJECT or derived.
77 #define G_IS_OBJECT_CLASS(class) (G_TYPE_CHECK_CLASS_TYPE ((class), G_TYPE_OBJECT))
80 * @object: a #GObject instance.
82 * Get the class structure associated to a #GObject instance.
84 * Returns: pointer to object class structure.
86 #define G_OBJECT_GET_CLASS(object) (G_TYPE_INSTANCE_GET_CLASS ((object), G_TYPE_OBJECT, GObjectClass))
89 * @object: Object to return the type id for.
91 * Get the type id of an object.
93 * Returns: Type id of @object.
95 #define G_OBJECT_TYPE(object) (G_TYPE_FROM_INSTANCE (object))
98 * @object: Object to return the type name for.
100 * Get the name of an object's type.
102 * Returns: Type name of @object. The string is owned by the type system and
103 * should not be freed.
105 #define G_OBJECT_TYPE_NAME(object) (g_type_name (G_OBJECT_TYPE (object)))
107 * G_OBJECT_CLASS_TYPE:
108 * @class: a valid #GObjectClass
110 * Get the type id of a class structure.
112 * Returns: Type id of @class.
114 #define G_OBJECT_CLASS_TYPE(class) (G_TYPE_FROM_CLASS (class))
116 * G_OBJECT_CLASS_NAME:
117 * @class: a valid #GObjectClass
119 * Return the name of a class structure's type.
121 * Returns: Type name of @class. The string is owned by the type system and
122 * should not be freed.
124 #define G_OBJECT_CLASS_NAME(class) (g_type_name (G_OBJECT_CLASS_TYPE (class)))
126 * G_VALUE_HOLDS_OBJECT:
127 * @value: a valid #GValue structure
129 * Checks whether the given #GValue can hold values derived from type %G_TYPE_OBJECT.
131 * Returns: %TRUE on success.
133 #define G_VALUE_HOLDS_OBJECT(value) (G_TYPE_CHECK_VALUE_TYPE ((value), G_TYPE_OBJECT))
135 /* --- type macros --- */
137 * G_TYPE_INITIALLY_UNOWNED:
139 * The type for #GInitiallyUnowned.
141 #define G_TYPE_INITIALLY_UNOWNED (g_initially_unowned_get_type())
143 * G_INITIALLY_UNOWNED:
144 * @object: Object which is subject to casting.
146 * Casts a #GInitiallyUnowned or derived pointer into a (GInitiallyUnowned*)
147 * pointer. Depending on the current debugging level, this function may invoke
148 * certain runtime checks to identify invalid casts.
150 #define G_INITIALLY_UNOWNED(object) (G_TYPE_CHECK_INSTANCE_CAST ((object), G_TYPE_INITIALLY_UNOWNED, GInitiallyUnowned))
152 * G_INITIALLY_UNOWNED_CLASS:
153 * @class: a valid #GInitiallyUnownedClass
155 * Casts a derived #GInitiallyUnownedClass structure into a
156 * #GInitiallyUnownedClass structure.
158 #define G_INITIALLY_UNOWNED_CLASS(class) (G_TYPE_CHECK_CLASS_CAST ((class), G_TYPE_INITIALLY_UNOWNED, GInitiallyUnownedClass))
160 * G_IS_INITIALLY_UNOWNED:
161 * @object: Instance to check for being a %G_TYPE_INITIALLY_UNOWNED.
163 * Checks whether a valid #GTypeInstance pointer is of type %G_TYPE_INITIALLY_UNOWNED.
165 #define G_IS_INITIALLY_UNOWNED(object) (G_TYPE_CHECK_INSTANCE_TYPE ((object), G_TYPE_INITIALLY_UNOWNED))
167 * G_IS_INITIALLY_UNOWNED_CLASS:
168 * @class: a #GInitiallyUnownedClass
170 * Checks whether @class "is a" valid #GInitiallyUnownedClass structure of type
171 * %G_TYPE_INITIALLY_UNOWNED or derived.
173 #define G_IS_INITIALLY_UNOWNED_CLASS(class) (G_TYPE_CHECK_CLASS_TYPE ((class), G_TYPE_INITIALLY_UNOWNED))
175 * G_INITIALLY_UNOWNED_GET_CLASS:
176 * @object: a #GInitiallyUnowned instance.
178 * Get the class structure associated to a #GInitiallyUnowned instance.
180 * Returns: pointer to object class structure.
182 #define G_INITIALLY_UNOWNED_GET_CLASS(object) (G_TYPE_INSTANCE_GET_CLASS ((object), G_TYPE_INITIALLY_UNOWNED, GInitiallyUnownedClass))
183 /* GInitiallyUnowned ia a GObject with initially floating reference count */
186 /* --- typedefs & structures --- */
187 typedef struct _GObject GObject
;
188 typedef struct _GObjectClass GObjectClass
;
189 typedef struct _GObject GInitiallyUnowned
;
190 typedef struct _GObjectClass GInitiallyUnownedClass
;
191 typedef struct _GObjectConstructParam GObjectConstructParam
;
193 * GObjectGetPropertyFunc:
194 * @object: a #GObject
195 * @property_id: the numeric id under which the property was registered with
196 * g_object_class_install_property().
197 * @value: a #GValue to return the property value in
198 * @pspec: the #GParamSpec describing the property
200 * The type of the @get_property function of #GObjectClass.
202 typedef void (*GObjectGetPropertyFunc
) (GObject
*object
,
207 * GObjectSetPropertyFunc:
208 * @object: a #GObject
209 * @property_id: the numeric id under which the property was registered with
210 * g_object_class_install_property().
211 * @value: the new value for the property
212 * @pspec: the #GParamSpec describing the property
214 * The type of the @set_property function of #GObjectClass.
216 typedef void (*GObjectSetPropertyFunc
) (GObject
*object
,
221 * GObjectFinalizeFunc:
222 * @object: the #GObject being finalized
224 * The type of the @finalize function of #GObjectClass.
226 typedef void (*GObjectFinalizeFunc
) (GObject
*object
);
229 * @data: data that was provided when the weak reference was established
230 * @where_the_object_was: the object being finalized
232 * A #GWeakNotify function can be added to an object as a callback that gets
233 * triggered when the object is finalized. Since the object is already being
234 * finalized when the #GWeakNotify is called, there's not much you could do
235 * with the object, apart from e.g. using its address as hash-index or the like.
237 typedef void (*GWeakNotify
) (gpointer data
,
238 GObject
*where_the_object_was
);
242 * All the fields in the GObject structure are private
243 * to the #GObject implementation and should never be accessed directly.
247 GTypeInstance g_type_instance
;
250 volatile guint ref_count
;
255 * @g_type_class: the parent class
256 * @constructor: the @constructor function is called by g_object_new () to
257 * complete the object initialization after all the construction properties are
258 * set. The first thing a @constructor implementation must do is chain up to the
259 * @constructor of the parent class. Overriding @constructor should be rarely
260 * needed, e.g. to handle construct properties, or to implement singletons.
261 * @set_property: the generic setter for all properties of this type. Should be
262 * overridden for every type with properties. If implementations of
263 * @set_property don't emit property change notification explicitly, this will
264 * be done implicitly by the type system. However, if the notify signal is
265 * emitted explicitly, the type system will not emit it a second time.
266 * @get_property: the generic getter for all properties of this type. Should be
267 * overridden for every type with properties.
268 * @dispose: the @dispose function is supposed to drop all references to other
269 * objects, but keep the instance otherwise intact, so that client method
270 * invocations still work. It may be run multiple times (due to reference
271 * loops). Before returning, @dispose should chain up to the @dispose method
272 * of the parent class.
273 * @finalize: instance finalization function, should finish the finalization of
274 * the instance begun in @dispose and chain up to the @finalize method of the
276 * @dispatch_properties_changed: emits property change notification for a bunch
277 * of properties. Overriding @dispatch_properties_changed should be rarely
279 * @notify: the class closure for the notify signal
280 * @constructed: the @constructed function is called by g_object_new() as the
281 * final step of the object creation process. At the point of the call, all
282 * construction properties have been set on the object. The purpose of this
283 * call is to allow for object initialisation steps that can only be performed
284 * after construction properties have been set. @constructed implementors
285 * should chain up to the @constructed call of their parent class to allow it
286 * to complete its initialisation.
288 * The class structure for the GObject type.
290 * |[<!-- language="C" -->
291 * // Example of implementing a singleton using a constructor.
292 * static MySingleton *the_singleton = NULL;
295 * my_singleton_constructor (GType type,
296 * guint n_construct_params,
297 * GObjectConstructParam *construct_params)
301 * if (!the_singleton)
303 * object = G_OBJECT_CLASS (parent_class)->constructor (type,
304 * n_construct_params,
306 * the_singleton = MY_SINGLETON (object);
309 * object = g_object_ref (G_OBJECT (the_singleton));
317 GTypeClass g_type_class
;
320 GSList
*construct_properties
;
323 /* seldom overidden */
324 GObject
* (*constructor
) (GType type
,
325 guint n_construct_properties
,
326 GObjectConstructParam
*construct_properties
);
327 /* overridable methods */
328 void (*set_property
) (GObject
*object
,
332 void (*get_property
) (GObject
*object
,
336 void (*dispose
) (GObject
*object
);
337 void (*finalize
) (GObject
*object
);
338 /* seldom overidden */
339 void (*dispatch_properties_changed
) (GObject
*object
,
341 GParamSpec
**pspecs
);
343 void (*notify
) (GObject
*object
,
346 /* called when done constructing */
347 void (*constructed
) (GObject
*object
);
356 * GObjectConstructParam:
357 * @pspec: the #GParamSpec of the construct parameter
358 * @value: the value to set the parameter to
360 * The GObjectConstructParam struct is an auxiliary
361 * structure used to hand #GParamSpec/#GValue pairs to the @constructor of
364 struct _GObjectConstructParam
373 * All the fields in the GInitiallyUnowned structure
374 * are private to the #GInitiallyUnowned implementation and should never be
378 * GInitiallyUnownedClass:
380 * The class structure for the GInitiallyUnowned type.
384 /* --- prototypes --- */
385 GLIB_AVAILABLE_IN_ALL
386 GType
g_initially_unowned_get_type (void);
387 GLIB_AVAILABLE_IN_ALL
388 void g_object_class_install_property (GObjectClass
*oclass
,
391 GLIB_AVAILABLE_IN_ALL
392 GParamSpec
* g_object_class_find_property (GObjectClass
*oclass
,
393 const gchar
*property_name
);
394 GLIB_AVAILABLE_IN_ALL
395 GParamSpec
**g_object_class_list_properties (GObjectClass
*oclass
,
396 guint
*n_properties
);
397 GLIB_AVAILABLE_IN_ALL
398 void g_object_class_override_property (GObjectClass
*oclass
,
401 GLIB_AVAILABLE_IN_ALL
402 void g_object_class_install_properties (GObjectClass
*oclass
,
404 GParamSpec
**pspecs
);
406 GLIB_AVAILABLE_IN_ALL
407 void g_object_interface_install_property (gpointer g_iface
,
409 GLIB_AVAILABLE_IN_ALL
410 GParamSpec
* g_object_interface_find_property (gpointer g_iface
,
411 const gchar
*property_name
);
412 GLIB_AVAILABLE_IN_ALL
413 GParamSpec
**g_object_interface_list_properties (gpointer g_iface
,
414 guint
*n_properties_p
);
416 GLIB_AVAILABLE_IN_ALL
417 GType
g_object_get_type (void) G_GNUC_CONST
;
418 GLIB_AVAILABLE_IN_ALL
419 gpointer
g_object_new (GType object_type
,
420 const gchar
*first_property_name
,
422 GLIB_AVAILABLE_IN_2_54
423 GObject
* g_object_new_with_properties (GType object_type
,
426 const GValue values
[]);
427 GLIB_DEPRECATED_IN_2_54_FOR(g_object_new_with_properties
)
428 gpointer
g_object_newv (GType object_type
,
430 GParameter
*parameters
);
431 GLIB_AVAILABLE_IN_ALL
432 GObject
* g_object_new_valist (GType object_type
,
433 const gchar
*first_property_name
,
435 GLIB_AVAILABLE_IN_ALL
436 void g_object_set (gpointer object
,
437 const gchar
*first_property_name
,
438 ...) G_GNUC_NULL_TERMINATED
;
439 GLIB_AVAILABLE_IN_ALL
440 void g_object_get (gpointer object
,
441 const gchar
*first_property_name
,
442 ...) G_GNUC_NULL_TERMINATED
;
443 GLIB_AVAILABLE_IN_ALL
444 gpointer
g_object_connect (gpointer object
,
445 const gchar
*signal_spec
,
446 ...) G_GNUC_NULL_TERMINATED
;
447 GLIB_AVAILABLE_IN_ALL
448 void g_object_disconnect (gpointer object
,
449 const gchar
*signal_spec
,
450 ...) G_GNUC_NULL_TERMINATED
;
451 GLIB_AVAILABLE_IN_2_54
452 void g_object_setv (GObject
*object
,
454 const gchar
*names
[],
455 const GValue values
[]);
456 GLIB_AVAILABLE_IN_ALL
457 void g_object_set_valist (GObject
*object
,
458 const gchar
*first_property_name
,
460 GLIB_AVAILABLE_IN_2_54
461 void g_object_getv (GObject
*object
,
463 const gchar
*names
[],
465 GLIB_AVAILABLE_IN_ALL
466 void g_object_get_valist (GObject
*object
,
467 const gchar
*first_property_name
,
469 GLIB_AVAILABLE_IN_ALL
470 void g_object_set_property (GObject
*object
,
471 const gchar
*property_name
,
472 const GValue
*value
);
473 GLIB_AVAILABLE_IN_ALL
474 void g_object_get_property (GObject
*object
,
475 const gchar
*property_name
,
477 GLIB_AVAILABLE_IN_ALL
478 void g_object_freeze_notify (GObject
*object
);
479 GLIB_AVAILABLE_IN_ALL
480 void g_object_notify (GObject
*object
,
481 const gchar
*property_name
);
482 GLIB_AVAILABLE_IN_ALL
483 void g_object_notify_by_pspec (GObject
*object
,
485 GLIB_AVAILABLE_IN_ALL
486 void g_object_thaw_notify (GObject
*object
);
487 GLIB_AVAILABLE_IN_ALL
488 gboolean
g_object_is_floating (gpointer object
);
489 GLIB_AVAILABLE_IN_ALL
490 gpointer
g_object_ref_sink (gpointer object
);
491 GLIB_AVAILABLE_IN_ALL
492 gpointer
g_object_ref (gpointer object
);
493 GLIB_AVAILABLE_IN_ALL
494 void g_object_unref (gpointer object
);
495 GLIB_AVAILABLE_IN_ALL
496 void g_object_weak_ref (GObject
*object
,
499 GLIB_AVAILABLE_IN_ALL
500 void g_object_weak_unref (GObject
*object
,
503 GLIB_AVAILABLE_IN_ALL
504 void g_object_add_weak_pointer (GObject
*object
,
505 gpointer
*weak_pointer_location
);
506 GLIB_AVAILABLE_IN_ALL
507 void g_object_remove_weak_pointer (GObject
*object
,
508 gpointer
*weak_pointer_location
);
510 #if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_56
511 /* Make reference APIs type safe with macros */
512 #define g_object_ref(Obj) ((__typeof__(Obj)) (g_object_ref) (Obj))
513 #define g_object_ref_sink(Obj) ((__typeof__(Obj)) (g_object_ref_sink) (Obj))
518 * @data: Callback data passed to g_object_add_toggle_ref()
519 * @object: The object on which g_object_add_toggle_ref() was called.
520 * @is_last_ref: %TRUE if the toggle reference is now the
521 * last reference to the object. %FALSE if the toggle
522 * reference was the last reference and there are now other
525 * A callback function used for notification when the state
526 * of a toggle reference changes. See g_object_add_toggle_ref().
528 typedef void (*GToggleNotify
) (gpointer data
,
530 gboolean is_last_ref
);
532 GLIB_AVAILABLE_IN_ALL
533 void g_object_add_toggle_ref (GObject
*object
,
534 GToggleNotify notify
,
536 GLIB_AVAILABLE_IN_ALL
537 void g_object_remove_toggle_ref (GObject
*object
,
538 GToggleNotify notify
,
541 GLIB_AVAILABLE_IN_ALL
542 gpointer
g_object_get_qdata (GObject
*object
,
544 GLIB_AVAILABLE_IN_ALL
545 void g_object_set_qdata (GObject
*object
,
548 GLIB_AVAILABLE_IN_ALL
549 void g_object_set_qdata_full (GObject
*object
,
552 GDestroyNotify destroy
);
553 GLIB_AVAILABLE_IN_ALL
554 gpointer
g_object_steal_qdata (GObject
*object
,
557 GLIB_AVAILABLE_IN_2_34
558 gpointer
g_object_dup_qdata (GObject
*object
,
560 GDuplicateFunc dup_func
,
562 GLIB_AVAILABLE_IN_2_34
563 gboolean
g_object_replace_qdata (GObject
*object
,
567 GDestroyNotify destroy
,
568 GDestroyNotify
*old_destroy
);
570 GLIB_AVAILABLE_IN_ALL
571 gpointer
g_object_get_data (GObject
*object
,
573 GLIB_AVAILABLE_IN_ALL
574 void g_object_set_data (GObject
*object
,
577 GLIB_AVAILABLE_IN_ALL
578 void g_object_set_data_full (GObject
*object
,
581 GDestroyNotify destroy
);
582 GLIB_AVAILABLE_IN_ALL
583 gpointer
g_object_steal_data (GObject
*object
,
586 GLIB_AVAILABLE_IN_2_34
587 gpointer
g_object_dup_data (GObject
*object
,
589 GDuplicateFunc dup_func
,
591 GLIB_AVAILABLE_IN_2_34
592 gboolean
g_object_replace_data (GObject
*object
,
596 GDestroyNotify destroy
,
597 GDestroyNotify
*old_destroy
);
600 GLIB_AVAILABLE_IN_ALL
601 void g_object_watch_closure (GObject
*object
,
603 GLIB_AVAILABLE_IN_ALL
604 GClosure
* g_cclosure_new_object (GCallback callback_func
,
606 GLIB_AVAILABLE_IN_ALL
607 GClosure
* g_cclosure_new_object_swap (GCallback callback_func
,
609 GLIB_AVAILABLE_IN_ALL
610 GClosure
* g_closure_new_object (guint sizeof_closure
,
612 GLIB_AVAILABLE_IN_ALL
613 void g_value_set_object (GValue
*value
,
615 GLIB_AVAILABLE_IN_ALL
616 gpointer
g_value_get_object (const GValue
*value
);
617 GLIB_AVAILABLE_IN_ALL
618 gpointer
g_value_dup_object (const GValue
*value
);
619 GLIB_AVAILABLE_IN_ALL
620 gulong
g_signal_connect_object (gpointer instance
,
621 const gchar
*detailed_signal
,
624 GConnectFlags connect_flags
);
627 GLIB_AVAILABLE_IN_ALL
628 void g_object_force_floating (GObject
*object
);
629 GLIB_AVAILABLE_IN_ALL
630 void g_object_run_dispose (GObject
*object
);
633 GLIB_AVAILABLE_IN_ALL
634 void g_value_take_object (GValue
*value
,
636 GLIB_DEPRECATED_FOR(g_value_take_object
)
637 void g_value_set_object_take_ownership (GValue
*value
,
641 gsize
g_object_compat_control (gsize what
,
644 /* --- implementation macros --- */
645 #define G_OBJECT_WARN_INVALID_PSPEC(object, pname, property_id, pspec) \
647 GObject *_glib__object = (GObject*) (object); \
648 GParamSpec *_glib__pspec = (GParamSpec*) (pspec); \
649 guint _glib__property_id = (property_id); \
650 g_warning ("%s:%d: invalid %s id %u for \"%s\" of type '%s' in '%s'", \
651 __FILE__, __LINE__, \
653 _glib__property_id, \
654 _glib__pspec->name, \
655 g_type_name (G_PARAM_SPEC_TYPE (_glib__pspec)), \
656 G_OBJECT_TYPE_NAME (_glib__object)); \
659 * G_OBJECT_WARN_INVALID_PROPERTY_ID:
660 * @object: the #GObject on which set_property() or get_property() was called
661 * @property_id: the numeric id of the property
662 * @pspec: the #GParamSpec of the property
664 * This macro should be used to emit a standard warning about unexpected
665 * properties in set_property() and get_property() implementations.
667 #define G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec) \
668 G_OBJECT_WARN_INVALID_PSPEC ((object), "property", (property_id), (pspec))
670 GLIB_AVAILABLE_IN_ALL
671 void g_clear_object (volatile GObject
**object_ptr
);
672 #define g_clear_object(object_ptr) g_clear_pointer ((object_ptr), g_object_unref)
675 * g_set_object: (skip)
676 * @object_ptr: a pointer to a #GObject reference
677 * @new_object: (nullable) (transfer none): a pointer to the new #GObject to
678 * assign to it, or %NULL to clear the pointer
680 * Updates a #GObject pointer to refer to @new_object. It increments the
681 * reference count of @new_object (if non-%NULL), decrements the reference
682 * count of the current value of @object_ptr (if non-%NULL), and assigns
683 * @new_object to @object_ptr. The assignment is not atomic.
685 * @object_ptr must not be %NULL.
687 * A macro is also included that allows this function to be used without
688 * pointer casts. The function itself is static inline, so its address may vary
689 * between compilation units.
691 * One convenient usage of this function is in implementing property setters:
694 * foo_set_bar (Foo *foo,
697 * g_return_if_fail (IS_FOO (foo));
698 * g_return_if_fail (new_bar == NULL || IS_BAR (new_bar));
700 * if (g_set_object (&foo->bar, new_bar))
701 * g_object_notify (foo, "bar");
705 * Returns: %TRUE if the value of @object_ptr changed, %FALSE otherwise
709 static inline gboolean
710 (g_set_object
) (GObject
**object_ptr
,
713 GObject
*old_object
= *object_ptr
;
715 /* rely on g_object_[un]ref() to check the pointers are actually GObjects;
716 * elide a (object_ptr != NULL) check because most of the time we will be
717 * operating on struct members with a constant offset, so a NULL check would
721 if (old_object
== new_object
)
724 if (new_object
!= NULL
)
725 g_object_ref (new_object
);
727 *object_ptr
= new_object
;
729 if (old_object
!= NULL
)
730 g_object_unref (old_object
);
735 #define g_set_object(object_ptr, new_object) \
736 (/* Check types match. */ \
737 0 ? *(object_ptr) = (new_object), FALSE : \
738 (g_set_object) ((GObject **) (object_ptr), (GObject *) (new_object)) \
742 * g_clear_weak_pointer: (skip)
743 * @weak_pointer_location: The memory address of a pointer
745 * Clears a weak reference to a #GObject.
747 * @weak_pointer_location must not be %NULL.
749 * If the weak reference is %NULL then this function does nothing.
750 * Otherwise, the weak reference to the object is removed for that location
751 * and the pointer is set to %NULL.
753 * A macro is also included that allows this function to be used without
754 * pointer casts. The function itself is static inline, so its address may vary
755 * between compilation units.
760 (g_clear_weak_pointer
) (gpointer
*weak_pointer_location
)
762 GObject
*object
= (GObject
*) *weak_pointer_location
;
766 g_object_remove_weak_pointer (object
, weak_pointer_location
);
767 *weak_pointer_location
= NULL
;
771 #define g_clear_weak_pointer(weak_pointer_location) \
772 (/* Check types match. */ \
773 (g_clear_weak_pointer) ((gpointer *) (weak_pointer_location)) \
777 * g_set_weak_pointer: (skip)
778 * @weak_pointer_location: the memory address of a pointer
779 * @new_object: (nullable) (transfer none): a pointer to the new #GObject to
780 * assign to it, or %NULL to clear the pointer
782 * Updates a pointer to weakly refer to @new_object. It assigns @new_object
783 * to @weak_pointer_location and ensures that @weak_pointer_location will
784 * automaticaly be set to %NULL if @new_object gets destroyed. The assignment
785 * is not atomic. The weak reference is not thread-safe, see
786 * g_object_add_weak_pointer() for details.
788 * @weak_pointer_location must not be %NULL.
790 * A macro is also included that allows this function to be used without
791 * pointer casts. The function itself is static inline, so its address may vary
792 * between compilation units.
794 * One convenient usage of this function is in implementing property setters:
797 * foo_set_bar (Foo *foo,
800 * g_return_if_fail (IS_FOO (foo));
801 * g_return_if_fail (new_bar == NULL || IS_BAR (new_bar));
803 * if (g_set_weak_pointer (&foo->bar, new_bar))
804 * g_object_notify (foo, "bar");
808 * Returns: %TRUE if the value of @weak_pointer_location changed, %FALSE otherwise
812 static inline gboolean
813 (g_set_weak_pointer
) (gpointer
*weak_pointer_location
,
816 GObject
*old_object
= (GObject
*) *weak_pointer_location
;
818 /* elide a (weak_pointer_location != NULL) check because most of the time we
819 * will be operating on struct members with a constant offset, so a NULL
820 * check would not catch bugs
823 if (old_object
== new_object
)
826 if (old_object
!= NULL
)
827 g_object_remove_weak_pointer (old_object
, weak_pointer_location
);
829 *weak_pointer_location
= new_object
;
831 if (new_object
!= NULL
)
832 g_object_add_weak_pointer (new_object
, weak_pointer_location
);
837 #define g_set_weak_pointer(weak_pointer_location, new_object) \
838 (/* Check types match. */ \
839 0 ? *(weak_pointer_location) = (new_object), FALSE : \
840 (g_set_weak_pointer) ((gpointer *) (weak_pointer_location), (GObject *) (new_object)) \
845 union { gpointer p
; } priv
;
848 GLIB_AVAILABLE_IN_ALL
849 void g_weak_ref_init (GWeakRef
*weak_ref
,
851 GLIB_AVAILABLE_IN_ALL
852 void g_weak_ref_clear (GWeakRef
*weak_ref
);
853 GLIB_AVAILABLE_IN_ALL
854 gpointer
g_weak_ref_get (GWeakRef
*weak_ref
);
855 GLIB_AVAILABLE_IN_ALL
856 void g_weak_ref_set (GWeakRef
*weak_ref
,
861 #endif /* __G_OBJECT_H__ */