10.9.11 Coexisting with Attributes and Blocked Goals

Domain variables may have attributes from other modules, as well as blocked goals, attached to them. However, the CLPFD propagation phase runs to completion before invoking handlers for such attributes and resuming such blocked goals. This could mean in particular that upon completion of the propagation phase, attribute handlers and blocked goals for multiple variables are ready to execute. For details, see the verify_attributes/3 hook at lib-atts.

Please note: fd_purge(X) (see Forgetting Constraints) does not affect attributes of other modules, or blocked goals.

Please note: the garbage collector will preserve all variables with attached attributes or blocked goals.