Copyright (1997-2013) EDMGROUP Pty Ltd - EZY Prolog Reference


New in EZY Prolog Tutorials Download EZY Prolog main page


EZY Designing

EZY Prolog basics

EZY GUI and Visual Prolog

EZY Debugger

EZY Code Generator


EZY Read/Write

EZY Lists

EZY Dialogs

EZY Menu


EZY Programming

EZY Samples



EZY Tree and XTree

EZY Regular expressions

EZY DDE (Dynamic Data Exchange)

Data type checking/conversion

Execution control

Term unification


File system

Operating system

Date/Time functions

String operations

Built-in WEB Browser

Internal Databases


HTML support

EZY Prolog Domains

EZY Prolog Functions

EZY Prolog versions

EZY Prolog allows to load and pass control into external Dynamic Linked Library (DLL) and receive results from it.

EZY Prolog provides deterministic and non-deterministic calls to the DLL's deterministic functions. System uses strings to pass parameters between EZY Prolog and DLL functions.

Programmers can use powerful term_str function to convert facts to strings and back inside EZY Prolog and Visual Prolog code.

EZY DLL subsystem allows to define event handler for the Frame inside user dll. See Frame test for more information

EZY DLL subsystem allows to implement custom controls via Visual Prolog DLL.


Conditions of use:

  • DLL is loaded dynamically. Full qualified path should be specified

  • DLL functional calls should be exported (see Visual Prolog 5.2 sample DLL )

  • It is not allowed to fail inside DLL - it should always return values (please consult Visual Prolog 5.2 documentation regarding DLL use)

  • DLL functional call has 3 parameters:
    with flow patterns:

  • DLL should return result of execution inside INTEGER parameter.
    If RESULT = 1 - EZY Prolog will continue execution of program.
    If RESULT = 0 - EZY Prolog rule fails (note: DLL CAN'T FAIL)

Click here to view EZY DLL functional calls


Click here to view EZY Prolog sample with external DLL call, which simulates calls, such as:

  • assert

  • retract

  • findall

inside Visual Prolog DLL


Click here to view EZY Prolog sample with external DLL call, which processes EVENTs inside Visual Prolog  DLL.


Click here to download Visual Prolog 5.2 sample DLL project (12 kb ZIP file)





Copyright 1997-2013 EDMGROUP (Australia)

Last Updated:

November 14, 2008