Programs Explains program structure basics and global instructions/registers. Structure of a program The structure of a program consists of MAIN and FUNCTION blocks defined in several modules. Structure of a module A module defines a set of program elements such as functions, report routines, types, constants and variables. The MAIN block / function The MAIN block is the starting point of the program. Importing modules Use the IMPORT ... instruction to import BDL, C or Java external modules in the current module. Predefined constants The language defines a set of global constants that can be used in the programs. Configuration options Compiler and runtime system can be controlled with several configuration settings. Program registers Predefined global registers can be used in programs to detect errors, signals and events.