public bool extend_with_template (Object object, Type template_type, string buffer, ssize_t length) throws Error
Main private entry point for building composite components from template XML.
Most likely you do not need to call this function in applications as templates are handled by `GtkWidget`.
the object that is being extended
the type that the template is for
the string to parse
the length of
A positive value on success, 0 if an error occurred