4.15.3 Handling Exceptions

• ref-ere-hex-pgo: Protecting a Particular Goal
• ref-ere-hex-hup: Handling Unknown Predicates

It is possible to protect a part of a program against abrupt termination in the event of an exception. There are two ways to do this:

• Trap exceptions to a particular goal by calling on_exception/3 as described in ref-ere-hex-pgo.
• Handle undefined predicates or subsets of them through the hook predicate user:unknown_predicate_handler/3; see ref-ere-hex-hup.