DFHCMACD

Enhanced Definition

`DFHCMACD` is a core CICS system module that contains the macro definitions for CICS command-level statements. It is primarily used by the CICS translator to convert `EXEC CICS` commands within application programs (COBOL, PL/I, Assembler) into standard language `CALL` statements that the native compiler can process. This module is fundamental for enabling high-level CICS application programming. DFHCMACD is the CICS **terminal auto-install control program**. It is invoked by CICS when a new terminal attempts to connect to the region and a corresponding resource definition does not already exist. Its primary purpose is to dynamically create a `TERMINAL` and `TYPETERM` definition in memory, allowing the terminal to connect and operate without requiring prior manual configuration in the CICS `CSD`.

Key Characteristics

- Translator Input: Serves as a crucial input for the CICS translator, providing the syntax and structure for all CICS command-level macros.
- Macro Expansion: Defines how CICS commands (e.g., EXEC CICS SEND, EXEC CICS RECEIVE, EXEC CICS LINK) are expanded into the corresponding CALL statements with specific parameters.
- Language Agnostic: Provides definitions that are utilized by the CICS translator for programs written in various languages, including COBOL, PL/I, and Assembler.
- Version Specific: Each CICS release typically comes with its own version of DFHCMACD, reflecting new commands, updated syntax, or deprecated features for that specific CICS environment.
- System Library Member: Resides in a CICS system library, typically SDFHLOAD, and is accessed by the CICS translator during the compilation process.
- Static Definitions: Contains static definitions that guide the translator's conversion process, ensuring consistency and correctness across CICS applications.

Use Cases

- CICS Application Compilation: Essential for the successful compilation of any CICS application program that uses EXEC CICS commands, as it enables the translator to understand and convert these commands.
- Program Development Workflow: Integrated into the standard CICS program development workflow, where source code containing CICS commands is first passed through the CICS translator before being compiled by the language compiler.
- Maintaining Compatibility: Ensures that CICS applications developed for a specific CICS version are translated correctly, leveraging the command set and syntax defined by that version's DFHCMACD.
- Debugging Translation Issues: Helps in diagnosing translation errors where an EXEC CICS command might be misspelled, incorrectly formatted, or not supported by the CICS version associated with the DFHCMACD module.

Related Concepts

DFHCMACD is intrinsically linked to the CICS Translator, which uses its definitions to convert high-level EXEC CICS commands into standard language CALL statements. This process is vital for CICS Application Programs written in languages like COBOL, allowing developers to use a simplified API. While DFHCMACD defines the *commands*, the CICS System Definition (CSD) defines the *resources* (e.g., programs, transactions, files) that these commands interact with at runtime. It forms a foundational part of the CICS API for command-level programming.

Best Practices:

Version Alignment: Always ensure that the DFHCMACD module used by the CICS translator during compilation matches the target CICS region's version to prevent runtime errors or unexpected behavior.
Automated Build Processes: Incorporate the CICS translation step, which implicitly relies on DFHCMACD, into automated JCL -based build and deployment pipelines for consistency and efficiency.
Error Analysis: When encountering CICS command-related translation errors, verify the command syntax against IBM CICS documentation and ensure the correct DFHCMACD version is being referenced.
Recompilation on Upgrade: After a CICS system upgrade, it is often a best practice to recompile existing CICS applications, especially if new CICS features are to be utilized, to ensure they are translated using the latest DFHCMACD definitions.