36.1 Introduction

FDBG is a CLP(FD) debugger for SICStus Prolog. Its main purpose is to enable the CLP programmer to trace the changes of domains of variables.

To load the package, enter the query

     | ?- use_module(library(fdbg)).

FDBG defines the following prefix operator:

     :- op(400, fy, #).

The presence of FDBG affects the translation and execution, but not the semantics, of subsequently loaded arithmetic constraints.