To allow users to produce code that cannot be debugged by others (for security reasons), Quintus Prolog 3.0 supports the concept of a locked predicate. A locked predicate will be treated by the debugger as opaque: users will not be able to creep into it. The debugger will behave in much the same way for locked predicates as it does for built-ins.
Predicates may be locked by specifying the
-h switch to
compiling a file. See the documentation for