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f44472e715
Now that g_object_ref() propagates the parameter type to the return value, we need to cast to ensure the result is warning free. https://bugzilla.gnome.org/show_bug.cgi?id=790697
85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/* GObject - GLib Type, Object, Parameter and Signal Library
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* Copyright (C) 2006 Imendio AB
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General
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* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#undef G_LOG_DOMAIN
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#define G_LOG_DOMAIN "TestSingleton"
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#include <glib-object.h>
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#include <string.h>
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/* --- MySingleton class --- */
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typedef struct {
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GObject parent_instance;
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} MySingleton;
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typedef struct {
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GObjectClass parent_class;
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} MySingletonClass;
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static GType my_singleton_get_type (void);
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#define MY_TYPE_SINGLETON (my_singleton_get_type ())
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#define MY_SINGLETON(o) (G_TYPE_CHECK_INSTANCE_CAST ((o), MY_TYPE_SINGLETON, MySingleton))
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#define MY_IS_SINGLETON(o) (G_TYPE_CHECK_INSTANCE_TYPE ((o), MY_TYPE_SINGLETON))
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#define MY_SINGLETON_CLASS(c) (G_TYPE_CHECK_CLASS_CAST ((c), MY_TYPE_SINGLETON, MySingletonClass))
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#define MY_IS_SINGLETON_CLASS(c) (G_TYPE_CHECK_CLASS_TYPE ((c), MY_TYPE_SINGLETON))
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#define MY_SINGLETON_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), MY_TYPE_SINGLETON, MySingletonClass))
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G_DEFINE_TYPE (MySingleton, my_singleton, G_TYPE_OBJECT)
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static MySingleton *the_one_and_only = NULL;
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/* --- methods --- */
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static GObject*
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my_singleton_constructor (GType type,
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guint n_construct_properties,
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GObjectConstructParam *construct_properties)
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{
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if (the_one_and_only)
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return g_object_ref (G_OBJECT (the_one_and_only));
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else
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return G_OBJECT_CLASS (my_singleton_parent_class)->constructor (type, n_construct_properties, construct_properties);
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}
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static void
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my_singleton_init (MySingleton *self)
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{
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g_assert (the_one_and_only == NULL);
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the_one_and_only = self;
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}
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static void
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my_singleton_class_init (MySingletonClass *klass)
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{
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G_OBJECT_CLASS (klass)->constructor = my_singleton_constructor;
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}
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/* --- test program --- */
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int
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main (int argc,
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char *argv[])
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{
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MySingleton *singleton, *obj;
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/* create the singleton */
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singleton = g_object_new (MY_TYPE_SINGLETON, NULL);
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g_assert (singleton != NULL);
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/* assert _singleton_ creation */
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obj = g_object_new (MY_TYPE_SINGLETON, NULL);
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g_assert (singleton == obj);
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g_object_unref (obj);
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/* shutdown */
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g_object_unref (singleton);
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return 0;
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}
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