AS400/ i-Series Control Language (CL) is a set of commands that use to control operations and to request system related function on the IBM AS400 computer.
IBM provides CL as an integrated part of the OS/400 operating system, not as separate product.
CL commands can be used at least two ways:
1. by typing them individually onto an AS/400 command line, or 2. by grouping them together into a CL program
CL programs typically consist of multiple CL commands that define procedures or operations on the AS/400. By combining multiple commands within a CL program, you can automate most AS/400 operation.
What CL Is Not
- CL is not high level language(HLL)
- CL is not use to create business application(example perform add or update records in a database file/table)
- CL have limited printing capabilities
- CL does not support the use of sub files within the application displays
- CL does not support individual fields in program describe files/table
Manipulations using CL, are limited to reading files and only a single file can be opened for I/O(Input/Output) operations. This make CL unsuitable for developing a complete business application.
Controlling Workflow with CL
CL programs control the workflow of an application by allowing you to create job-streams, which consist of CL commands to be executed in order.
Within a CL program you can:
- alter the order of execution by testing various conditions that may exist during the execution of a job.
- have statement/command to monitor for errors that might occur while running a job and perform corrective actions or abort the job
- incorporate conditional logic and
- special functions that are not available when you enter individual commands on the command line.
- pass values to and from CL programs
- pass parameters to and from CL programs
CL programs, unlike JCL(Job Control Language), are implemented as compiled program objects, rather than interpreted job streams. A CL program is a permanent object created by compiling a group of CL commands.
CL Execution Environment and Restrictions
CL command may be entered into the system interactively on command line or in a CL program. Individual CL commands and complied CL programs can be submitted for batch processing using the SBMJOB(Submit Job) command. Command can be included with a language procedure.
Another command SBMDBJOB(Submit Database Job) can be use for submitting for interpretation or compiled into a program object for batch processing.
Example of command that used interactively. STRSEU(Start Source Entry Utility).
Example of command that used within in batch process. CRTCLPGM(Complile a CL Program)
Example of commands that are valid within a CL program. GOTO and ENDPGM.
Example of a CL Program and is it output
Source member:
Output:
