A Prolog engine consists of a virtual machine state that includes the
Prolog stacks. An‘empty’engine requires about 20 KBytes
of memory. This grows when the engine requires additional stack space.
Anonymous engines are subject to atom garbage collection (see
garbage_collect_atoms/0).
Engines may be reclaimed immediately using
engine_destroy/1.
Calling engine_destroy/1
destroys the virtual machine state, while the handle itself is left to
atom garbage collection. The virtual machine is reclaimed as soon as an
engine produced its last result, failed or raised an exception. This
implies that it is only advantageous to call engine_destroy/1
explicitly if you are not interested in further answers.
Engines that are expected to be left in inactive state for a
prolonged time can be minimized by calling garbage_collect/0
and trim_stacks/0
(in that order) before calling engine_yield/1
or succeeding.
