set_filter_func

Sets the function used for filtering items.

If match_func is null, the filter matches all items.

If the filter func changes its filtering behavior, gtk_filter_changed needs to be called.

If a previous function was set, its user_destroy will be called now.

Parameters:

this	a `GtkCustomFilter`
match_func	function to filter items
user_data	user data to pass to match_func
user_destroy	destroy notify for user_data