gtypeplugin.h File Reference

__G_TYPE_PLUGIN_H__

G_TYPE_TYPE_PLUGIN

G_TYPE_PLUGIN

G_TYPE_PLUGIN_CLASS

G_IS_TYPE_PLUGIN

G_IS_TYPE_PLUGIN_CLASS

G_TYPE_PLUGIN_GET_CLASS

Typedef GTypePluginClass

typedef struct _GTypePluginClassGTypePluginClass

Typedef GTypePluginUse

typedef void(*GTypePluginUse

GTypePluginUse: : the GTypePlugin whose use count should be increased

The type of the function of GTypePluginClass, which gets called to increase the use count of .

Typedef GTypePluginUnuse

typedef void(*GTypePluginUnuse

GTypePluginUnuse: : the GTypePlugin whose use count should be decreased

The type of the function of GTypePluginClass.

Typedef GTypePluginCompleteTypeInfo

typedef void(*GTypePluginCompleteTypeInfo

GTypePluginCompleteTypeInfo: : the GTypePlugin : the GType whose info is completed : the GTypeInfo struct to fill in : the GTypeValueTable to fill in

The type of the function of GTypePluginClass.

Typedef GTypePluginCompleteInterfaceInfo

typedef void(*GTypePluginCompleteInterfaceInfo

GTypePluginCompleteInterfaceInfo: : the GTypePlugin : the GType of an instantiable type to which the interface is added : the GType of the interface whose info is completed : the GInterfaceInfo to fill in

The type of the function of GTypePluginClass.

g_type_plugin_get_type ( void )

IMPORT_C GTypeg_type_plugin_get_type(void)

SECTION:gtypeplugin : An interface for dynamically loadable types : GTypeModule and g_type_register_dynamic(). : GTypePlugin

The GObject type system supports dynamic loading of types. The GTypePlugin interface is used to handle the lifecycle of dynamically loaded types. It goes as follows:

<orderedlist> <listitem>

The type is initially introduced (usually upon loading the module the first time, or by your main application that knows what modules introduces what types), like this: |[ new_type_id = g_type_register_dynamic (parent_type_id, "TypeName", new_type_plugin, type_flags); ]| where <literal>new_type_plugin</literal> is an implementation of the GTypePlugin interface.

</listitem> <listitem>

The type's implementation is referenced, e.g. through g_type_class_ref() or through g_type_create_instance() (this is being called by g_object_new()) or through one of the above done on a type derived from <literal>new_type_id</literal>.

</listitem> <listitem>

This causes the type system to load the type's implementation by calling g_type_plugin_use() and g_type_plugin_complete_type_info() on <literal>new_type_plugin</literal>.

</listitem> <listitem>

At some point the type's implementation isn't required anymore, e.g. after g_type_class_unref() or g_type_free_instance() (called when the reference count of an instance drops to zero).

</listitem> <listitem>

This causes the type system to throw away the information retrieved from g_type_plugin_complete_type_info() and then it calls g_type_plugin_unuse() on <literal>new_type_plugin</literal>.

</listitem> <listitem>

Things may repeat from the second step.

</listitem> </orderedlist>

So basically, you need to implement a GTypePlugin type that carries a use_count, once use_count goes from zero to one, you need to load the implementation to successfully handle the upcoming g_type_plugin_complete_type_info() call. Later, maybe after succeeding use/unuse calls, once use_count drops to zero, you can unload the implementation again. The type system makes sure to call g_type_plugin_use() and g_type_plugin_complete_type_info() again when the type is needed again.

GTypeModule is an implementation of GTypePlugin that already implements most of this except for the actual module loading and unloading. It even handles multiple registered types per module.

g_type_plugin_use ( GTypePlugin * )

IMPORT_C voidg_type_plugin_use(GTypePlugin *plugin)

g_type_plugin_use: : a GTypePlugin

Calls the function from the GTypePluginClass of . There should be no need to use this function outside of the GObject type system itself.

g_type_plugin_unuse ( GTypePlugin * )

IMPORT_C voidg_type_plugin_unuse(GTypePlugin *plugin)

g_type_plugin_unuse: : a GTypePlugin

Calls the function from the GTypePluginClass of . There should be no need to use this function outside of the GObject type system itself.

g_type_plugin_complete_type_info ( GTypePlugin *, GType, GTypeInfo *, GTypeValueTable * )

IMPORT_C voidg_type_plugin_complete_type_info(GTypePlugin *plugin,
GTypeg_type,
GTypeInfo *info,
GTypeValueTable *value_table
)

g_type_plugin_complete_type_info: : a GTypePlugin : the GType whose info is completed : the GTypeInfo struct to fill in : the GTypeValueTable to fill in

Calls the function from the GTypePluginClass of . There should be no need to use this function outside of the GObject type system itself.

g_type_plugin_complete_interface_info ( GTypePlugin *, GType, GType, GInterfaceInfo * )

IMPORT_C voidg_type_plugin_complete_interface_info(GTypePlugin *plugin,
GTypeinstance_type,
GTypeinterface_type,
GInterfaceInfo *info
)

g_type_plugin_complete_interface_info: : the GTypePlugin : the GType of an instantiable type to which the interface is added : the GType of the interface whose info is completed : the GInterfaceInfo to fill in

Calls the function from the GTypePluginClass of . There should be no need to use this function outside of the GObject type system itself.