gtk:builder-application (builder)

builder -- a gtk:builder object
application -- a gtk:application instance

The gtk:builder-application function gets the application associated with the builder. The (setf gtk:builder-application) function sets the application.

The application is used for creating action proxies as requested from XML that the builder is loading. By default, the builder uses the default application: the one from the g:application-default function. If you want to use another application for constructing proxies, use the (setf gtk:builder-application) function.

You only need this function if there is more than one g:application instance in your process. The application argument cannot be nil.