CICS Commands Coding
CICS operations are performed by coding CICS commands in the application program. These CICS commands require a CICS command-level interface called EXECUTE CICS or EXEC CICS. When CICS service is required, The CICS commands should be coded in between EXEC CICS and END-EXEC to separate from application program coding. The commands coded in between EXEC CICS and END-EXEC should be understood by the CICS translator. The CICS translator translates these commands and converts as a call that suits the application program coding language during the compilation process.
EXEC CICS function option1 option2 ... END-EXEC.
The "function" is the action that requires to perform. An "option" is some specification that is associated with the function. Options are expressed as keywords.
Response codes of EXEC CICS commands
After an EXEC CICS command execution, fields EIBRESP and EIBRCODE are set to indicate whether the command executed successfully or a CICS condition was raised. We can use these response codes to help in validating the command execution status and problem determination if error occurs.
Each possible value of EIBRESP relates directly to a specific condition, no matter what command it is caused the error. Both the value and the byte of EIBRCODE is set depends on the command was issued.
How the CICS communicates to user?
CICS environment communicates to the user using terminating & reinitiating method which is called as Pseudo conversation. Pseudo Conversation discussed in the further chapters.