8 Built-In Predicates

SICStus Prolog provides a wide range of built-in predicates to perform all kinds of tasks; see the Table of Contents.

It is not possible to redefine built-in predicates. An attempt to do so will raise an exception. See Pred Summary.

When introducing a built-in predicate, we shall present its usage with a mode spec, and optionally with an annotation containing one or more of:

The predicate complies with the ISO Prolog Standard.
ISO only
The predicate variant described complies with the ISO Prolog Standard and is valid in the iso execution mode only.
SICStus only
The predicate variant described is valid in the sicstus execution mode only.
A declaration that can't be redefined as a predicate.
The predicate is not available in runtime systems.
The predicate is an extendible predicate.
The predicate is a hook predicate.
The predicate is a hookable predicate.
The predicate is obsolescent and should be avoided in new code.
A reserved construct that can't be defined as a predicate.

The following descriptions of the built-in predicates are grouped according to the above categorization of their tasks.