Interfacing Overview

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27 April 2015

This chapter provides a high-level overview of how to use and extend the external interfaces of the PLEXIL Executive.

Overview

The PLEXIL Application Framework provides a flexible mechanism for adding external interfaces to the PLEXIL Executive, and to applications built on the PLEXIL Application Framework.

PLEXIL Executive facilities

These artifacts are required to enable interaction between the PLEXIL Executive and an external system or environment:

  1. One or more shared library files which implement interface adapters and/or exec listeners (C++ code).
  2. An interface configuration file describing the adapters and listeners to be used.

Standard Interfaces

The PLEXIL distribution comes with several standard interface adapters and exec listeners; see Standard Libraries for a summary.

Configuration File

See Interface Configuration File for details.

Custom Interfaces

For an overview of developing your own custom adapters and listeners, please see Implementing Custom Interfaces.

Writing Your Own Application

In some applications, the user may prefer an executable which has all interfaces pre-loaded. In other situations, the operating system and/or build toolchain may not support dynamic loading of interface libraries. Or maybe the application requires that the executive run under the control of a real-time OS, in a particular threading enviroment.

In situations like these, it is straightforward to build a dedicated C++ executable which does exactly what the application requires. The process is outlined in Implementing Custom PLEXIL Applications.


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