This package loads the predicates and features that classical Prolog implementations provide by default (the 'built-ins'). This includes the ISO-Prolog predicates and features as well as others that are de-facto standard built-ins in most Prolog implementations. Consult the classic_predicates module for the listing of the concrete predicates that are available and the Ciao libraries they come from (see pointer below). Apart from these, the features defined in Definite Clause Grammars and Enabling operators at run-time are also activated.
The loading of this package can be controlled as described in the Library usage below and in The module system.
Note that :- module(modulename,exports) is equivalent to :- module(modulename,exports,[default]).
If you do not want these predicates/features loaded for a given file (e.g., for purity considerations, to aid analysis, to help making the executable smaller, etc.) you can ask for this explicitly using :- module(modulename,exports,). The same can be achieved in a user file using :- use_package() and in the top level by defining ~/.ciaorc (which can then include whatever alternative prelude is preferred).