engine_yield/1

Documentation
- Reference manual
  - Coroutining using Prolog engines
    - Engine predicate reference
- Packages

Availability:built-in

[det]engine_yield(+Term)

Called from within the engine, causing engine_next/2 in the caller to return with Term. A subsequent call to engine_next/2 causes engine_yield/1 to‘return’. This predicate can only be called if the engine is not involved in a callback from C, i.e., when the engine calls a predicate defined in C that calls back Prolog it is not possible to use this predicate. Trying to do so results in a permission_error exception.