g_object_ref
g_object_unref
g_object_ref_sink
+g_clear_object
GInitiallyUnowned
GInitiallyUnownedClass
G_TYPE_INITIALLY_UNOWNED
}
/**
+ * g_clear_object:
+ * @object_ptr: a pointer to a #GObject reference
+ *
+ * Clears a reference to a #GObject.
+ *
+ * @object_ptr must not be %NULL.
+ *
+ * If the reference is %NULL then this function does nothing.
+ * Otherwise, the reference count of the object is decreased and the
+ * pointer is set to %NULL.
+ *
+ * This function is threadsafe and modifies the pointer atomically,
+ * using memory barriers where needed.
+ *
+ * A macro is also included that allows this function to be used without
+ * pointer casts.
+ *
+ * Since: 2.28
+ **/
+#undef g_clear_object
+void
+g_clear_object (volatile GObject **object_ptr)
+{
+ gpointer *ptr = (gpointer) object_ptr;
+ gpointer old;
+
+ /* This is a little frustrating.
+ * Would be nice to have an atomic exchange (with no compare).
+ */
+ do
+ old = g_atomic_pointer_get (ptr);
+ while G_UNLIKELY (!g_atomic_pointer_compare_and_exchange (ptr, old, NULL));
+
+ if (old)
+ g_object_unref (old);
+}
+
+/**
* g_object_get_qdata:
* @object: The GObject to get a stored user data pointer from
* @quark: A #GQuark, naming the user data pointer
#define G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec) \
G_OBJECT_WARN_INVALID_PSPEC ((object), "property", (property_id), (pspec))
+void g_clear_object (volatile GObject **object_ptr);
+#define g_clear_object(object_ptr) \
+ G_STMT_START { \
+ /* Only one access, please */ \
+ gpointer *_p = (gpointer) (object_ptr); \
+ gpointer _o; \
+ \
+ do \
+ _o = g_atomic_pointer_get (_p); \
+ while G_UNLIKELY (!g_atomic_pointer_compare_and_exchange (_p, _o, NULL));\
+ \
+ if (_o) \
+ g_object_unref (_o); \
+ } G_STMT_END
+
G_END_DECLS
#endif /* __G_OBJECT_H__ */
g_value_set_object
g_value_dup_object
g_value_take_object
+g_clear_object
#ifndef G_DISABLE_DEPRECATED
g_value_set_object_take_ownership
g_object_compat_control
binding
dynamictests
properties
+reference
threadtests
noinst_PROGRAMS = $(TEST_PROGS)
libgobject_LDADD = ../libgobject-2.0.la $(top_builddir)/gthread/libgthread-2.0.la $(top_builddir)/glib/libglib-2.0.la
-TEST_PROGS += threadtests dynamictests binding properties
+TEST_PROGS += threadtests dynamictests binding properties reference
threadtests_SOURCES = threadtests.c
threadtests_LDADD = $(libgobject_LDADD)
dynamictests_SOURCES = dynamictests.c
binding_LDADD = $(libgobject_LDADD)
properties_SOURCES = properties.c
properties_LDADD = $(libgobject_LDADD)
+reference_LDADD = $(libgobject_LDADD)
--- /dev/null
+#include <glib-object.h>
+
+static void
+test_clear (void)
+{
+ GObject *o = NULL;
+ GObject *tmp;
+
+ g_clear_object (&o);
+ g_assert (o == NULL);
+
+ tmp = g_object_new (G_TYPE_OBJECT, NULL);
+ g_assert_cmpint (tmp->ref_count, ==, 1);
+ o = g_object_ref (tmp);
+ g_assert (o != NULL);
+
+ g_assert_cmpint (tmp->ref_count, ==, 2);
+ g_clear_object (&o);
+ g_assert_cmpint (tmp->ref_count, ==, 1);
+ g_assert (o == NULL);
+
+ g_object_unref (tmp);
+}
+
+int
+main (int argc, char **argv)
+{
+ g_test_init (&argc, &argv, NULL);
+
+ g_type_init ();
+
+ g_test_add_func ("/object/clear", test_clear);
+
+ return g_test_run ();
+}