21 Function Modules
In SAP ABAP, Function Modules are reusable procedures that encapsulate code for a specific task and are stored in a central library. They provide a fixed interface for data exchange, allowing them to be called from any ABAP program across the entire SAP system.
Core Characteristics
Encapsulation: Code is isolated within the module, promoting modularity and reducing redundancy.
Central Storage: Managed via the Function Builder (Transaction SE37).
Function Groups: Every function module must belong to a Function Group, which acts as a container for related modules and holds shared global data.
Fixed Interface: They use defined parameters—Import, Export, Changing, and Tables—and support Exception Handling to manage errors.