DFHEIB - Execute Interface Block

The `DFHEIB` (Execute Interface Block) is a CICS control block that provides an application program with information about the current task and the results of the most recently executed CICS command. It is automatically defined and populated by CICS for every task, serving as the primary communication area between CICS and the application program. The Execute Interface Block (DFHEIB) is a control block automatically created and managed by CICS (Customer Information Control System) for each active task. It serves as the primary communication area between a CICS application program (e.g., written in COBOL, PL/I, Assembler) and the CICS Transaction Server, providing crucial system and command-specific information.