Definition specifications can be used to define:
For more information on data structures, constants, prototypes, and procedure interfaces, see also Chapter 7. Defining Data and Prototypes For more information on data types and data formats, see also Chapter 9. Data Types and Data Formats.
Arrays and tables can be defined as either a data-structure subfield or a standalone field. For additional information on defining and using arrays and tables, see also Chapter 8. Using Arrays and Tables.
Definition specifications can appear in two places within a module or program: in the main source section and in a subprocedure. Within the main source section, you define all global definitions. Within a subprocedure, you define the procedure interface and its parameters as required by the prototype. You also define any local data items that are needed by the prototyped procedure when it is processed. Any definitions within a prototyped procedure are local. They are not known to any other procedures (including the cycle-main procedure). For more information on scope, see Scope of Definitions.
A built-in function (BIF) can be used in the keyword field as a parameter to a keyword. It is allowed on the definition specification only if the values of all arguments are known at compile time. When specified as parameters for the definition specification keywords DIM, OCCURS, OVERLAY, and PERRCD, all arguments for a BIF must be defined earlier in the program. For further information on using built-in functions, see Built-in Functions.
For more information on the layout and keywords used for the following definition types, see: