Name
GTypeModule -- Type Loading Modules
Description
GTypeModule provides a simple implementation of the GTypePlugin
interface. The model of GTypeModule is a dynamically loaded module
which implements some number of types and interface
implementations. When the module is loaded, it registerse its types
and interfaces using g_type_module_register_type() and
g_type_module_add_interface(). As long as any instances of these
types and interface implementations are in use, the module is kept
loaded. When the types and interfaces are gone, the module may be
unloaded. If the types and interfaces become used again, the module
will be reloaded.
Keeping track of whether the module should be loaded or not is done by
using a use count - it starts at zero, and whenever it is greater than
zero, the module is loaded. The use count is maintained internally by
the type system, but also can be explicitely controlled by
g_type_module_use() and g_type_module_unuse(). Typically, when loading
a module for the first type, g_type_module_use() will be used to load
it so that it can initialize its types. At some later point, when the
module no longer needs to be loaded except for the type
implementations it contains, g_type_module_unuse() is called.
GTypeModule does not actually provide any implementation of module
loading and unloading. To create a particular module type you must
derive from GTypeModule and implement the load and unload functions
in GTypeModuleClass.
Details
struct GTypeModule
struct GTypeModule
{
GObject parent_instance;
guint use_count;
GSList *type_infos;
GSList *interface_infos;
gchar *name;
}; |
g_type_module_use ()
Increases the use count of a GTypeModule by one. If the
use count was zero before, the plugin will be loaded.
g_type_module_unuse ()
Decreases the use count of a GTypeModule by one. If the
result is zero, the module will be unloaded. (However, the
GTypeModule will not be freed, and types associated with the
GTypeModule are not unregistered. Once a GTypeModule is
initialized, it must exist forever.)
g_type_module_set_name ()
Sets the name for a GTypeModule
g_type_module_register_type ()
Looks up or registers a type that is implemented with a particular
type plugin. If a type with name type_name is already registered,
the GType identifier for the type is returned, otherwise the type
is newly registered, and the resulting GType identifier returned.
As long as any instances of the type exist, the type plugin will
not be unloaded.
g_type_module_add_interface ()
Registers an additional interface for a type, whose interface
lives in the given type plugin. If the interface was already registered
for the type in this plugin, nothing will be done.
As long as any instances of the type exist, the type plugin will
not be unloaded.
See Also
- GTypePlugin
The abstract type loader interface.
- GModule
Portable mechanism for dynamically loaded modules.