2.12 Environment Control (Prolog flags)
All Application Manual Name SummaryHelp

Availability:built-in
pop_prolog_flag(:Key)
Restore the state saved by the matching push_prolog_flag/2. If Key did not exist at the matching push, it is removed again. Raises existence_error(pushed_flag, Key) if no matching push exists on the current thread.
ClioPatria (version V3.1.1-59-g7b9a7a3)