Execution/Language Interface

At the most fundamental level, EHLLAPI and HACL differ in the mechanics of how the API is called by an application program.

EHLLAPI is implemented as a single call-point interface with multiple-use parameters. A single entry point (hllapi) in a DLL provides all the functions based on a fixed set of four parameters. Three of the parameters take on different meanings depending on the value of the forth command parameter. This simple interface makes is easier to call the API from a variety of programming environments and languages. The disadvantage is a lot of complexity packed into one function and four parameters.

HACL is an object-oriented interface that provides a set of programming objects instead of explicit entry points or functions. The objects have properties and methods that can be used to manipulate a host connection. You do not have to be concerned with details of structure packing and parameter command codes, but can focus on the application functions. HACL objects can only be used from one of the supported HACL layer environments (C++ or Automation Objects). These three layers are accessible to most modern programming environments such as Microsoft Visual C++, Visual Basic and Lotus® SmartSuite® applications.