4.3 Loading Prolog source files
All Application Manual Name SummaryHelp

Availability:built-in
Sourceunload_file(+File)
Remove all clauses loaded from File. If File loaded a module, clear the module's export list and disassociate it from the file. File is a canonical filename or a file indicator that is valid for load_files/2.

This predicate should be used with care. The multithreaded nature of SWI-Prolog makes removing static code unsafe. Attempts to do this should be reserved for development or situations where the application can guarantee that none of the clauses associated to File are active.