IoExtensionPoint

GIOExtensionPoint provides a mechanism for modules to extend the functionality of the library or application that loaded it in an organized fashion.

An extension point is identified by a name, and it may optionally require that any implementation must be of a certain type (or derived thereof). Use func@Gio.IOExtensionPoint.register to register an extension point, and method@Gio.IOExtensionPoint.set_required_type to set a required type.

A module can implement an extension point by specifying the type@GObject.Type that implements the functionality. Additionally, each implementation of an extension point has a name, and a priority. Use func@Gio.IOExtensionPoint.implement to implement an extension point.

GIOExtensionPoint *ep;

// Register an extension point
ep = g_io_extension_point_register ("my-extension-point");
g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE);

// Implement an extension point
G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE)
g_io_extension_point_implement ("my-extension-point",
                                my_example_impl_get_type (),
                                "my-example",
                                10);

It is up to the code that registered the extension point how it uses the implementations that have been associated with it. Depending on the use case, it may use all implementations, or only the one with the highest priority, or pick a specific one by name.

To avoid opening all modules just to find out what extension points they implement, GIO makes use of a caching mechanism, see gio-querymodules.html. You are expected to run this command after installing a GIO module.

The GIO_EXTRA_MODULES environment variable can be used to specify additional directories to automatically load modules from. This environment variable has the same syntax as the PATH. If two modules have the same base name in different directories, then the latter one will be ignored. If additional directories are specified GIO will load modules from the built-in directory last.

Skipped during bindings generation

• method get_extension_by_name: Return type IOExtension is unsupported

• function implement: Return type IOExtension is unsupported

• function lookup: Return type IOExtensionPoint is unsupported

• function register: Return type IOExtensionPoint is unsupported