pub unsafe extern "C" fn gtk_source_completion_add_provider(
completion: *mut GtkSourceCompletion,
provider: *mut GtkSourceCompletionProvider,
error: *mut *mut GError
) -> gboolean
pub unsafe extern "C" fn gtk_source_completion_add_provider(
completion: *mut GtkSourceCompletion,
provider: *mut GtkSourceCompletionProvider,
error: *mut *mut GError
) -> gboolean