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JCL Tutorial - JCL Procedure |
Welcome to today's JCL tutorial on "JCL Procedure". In this session, you'll learn the basics of the JCL procedure, and how to code procedures in JCL. You'll also learn the type of JCL procedure i.e. Instream Procedure or Catalog procedures. Also, you will learn various IBM-supplied complex catalog procedures that let you interface easily with software products like compilers, CICS, and DB2, and you’ll use them all the time. So, let's start with the JCL Procedure tutorial agenda.
Procedures in JCL - Agenda.
- What is the JCL procedure?
- Advantage of JCL procedure.
- Catalog procedure in JCL.
- Instream procedure in JCL
What is JCL Procedure?
A JCL procedure (or just procedure in JCL) is a pre-written segment of code. JCL procedure consists of one or more job steps that you can include in a job stream (i.e. JCL). JCL procedures is divided into the following type:
- Catalog Procedure in JCL.
- Instream Procedure in JCL.
Now, let's discuss the advantage of procedure mainframe JCL's.
Advantage of procedure in JCLs.
The major advantage of procedure in JCL's is code reusability and code maintainability. By using procedures, the amount of JCL coding you have to do is reduced, resulting in fewer coding errors and greater productivity. Although you can code a JCL procedure directly in a single job stream, you’re more likely to invoke cataloged procedures that are available throughout an installation.
The syntax for invoking a JCL procedure
EXEC [PROC=]procedure-name
Note: The procedure name Identifies the procedure to be called and executed. For cataloged procedures, it’s the member name of the procedure. For instream procedures, it’s the name on the PROC statement that begins the procedure.
For example: In the middle of the below code, you can see the JCL statements that make up a cataloged procedure named XMP3000. This procedure consists of two job steps that execute the programs XMP3000 and allocate seven different data sets.
//RC01TN JOB (99992),'MAINFRAME',NOTIFY=MMTX01
//STEP01 EXEC XMP3000
//
Let's discuss the different JCL procedure categories i.e. CATALOG PROCEDURE and INSTREAM PROCEDURE.
What is CATALOG Procedure?
A cataloged procedure in JCL is a series of JCL statements that are stored in a partitioned data set and may be invoked by any job on the system (i.e. z/OS system). Whenever you invoke a cataloged procedure, the system looks for it in the system procedure library, SYS1.PROCLIB, unless you specify the library.
Although the PROC statement can be coded as the first statement in a cataloged procedure, it’s not required.
Example: CATALOGED PROCEDURE in JCL.
The cataloged JCL procedure named EMP3000 is invoked
//EMP3000 PROC
//EMP3010 EXEC PGM=EMP3000
//SYSOUT DD SYSOUT=*
//EMPMAST DD DSNAME=RCA2.PAYROL.MAST.FILE,DISP=SHR
//EMPSEL DD DSNAME=&&EMPSEL,DISP=(NEW,PASS,DELETE),
// UNIT=SYSDA,SPACE=(CYL,(120,10))
//*
//SAL3030 EXEC PGM=SAL3030
//SYSOUT DD SYSOUT=*
//INVMAST DD DSNAME=&&SALREP,DISP=(OLD,DELETE,DELETE)
//INVSLST DD SYSOUT=*
A mainframe job (i.e. JCL) that invokes a cataloged procedure in JCL.
//RC01TN JOB (99992),'MAINFRAME',NOTIFY=MMTX01
//STEP01 EXEC EMP3000
//
What is INSTREAM PROCEDURE?
An instream procedure consists of a PROC statement, any number of procedure steps, and a PEND statement. Then, you place the instream procedure near the beginning of your job stream, before any EXEC statement that refers to it. In contrast to a cataloged procedure, an instream procedure is available only to the job that contains it.
A name is always required on the PROC statement for an instream procedure. You can also specify a name on the PEND statement, but it’s optional.
JCL statements falling between the PROC and PEND statements are not executed when first encountered. Instead, they’re scanned for errors and retained as a temporary procedure.
Any JCL statements after the PEND statement are recognized as normal statements and are executed.
An instream procedure should be placed near the beginning of a job stream, before any EXEC statement that refers to it. The maximum number of instream procedures you can code in any job is 15.
Important Point: Before cataloging a procedure in a procedure library, it’s usually a good idea to test the JCL code it contains, and the easiest way to do that is with an instream procedure.
Example: INSTREAM PROCEDURE in JCL.
A job that instream data in JCL
//RC01TN JOB (99992),'MAINFRAME',NOTIFY=MMTX01
//TAX4000 PROC
//TAX3010 EXEC PGM=TAX3000
//SYSOUT DD SYSOUT=*
//TAXMAST DD DSNAME=RCA2.TAX.DED.FILE,DISP=SHR
//TAXSAL DD DSNAME=&&TAXDED,DISP=(NEW,PASS,DELETE),
// UNIT=SYSDA,SPACE=(CYL,(120,10))
// PEND
//EMP3030 EXEC PGM=TAX4000
//*
Youtube: Catalog procedure in JCL and Instream procedure in JCL.
The JCL Procedure tutorial is associated with a youtube video for good understanding. Please do watch this video and consider subscribing to our channel for more such tutorial video!
SYMBOLIC PARAMETER in INSTREAM DATA.
To code a symbolic parameter in a procedure, you use a name that starts with an ampersand (&). The name can be any meaningful name you want as long as it isn’t a keyword parameter on an EXEC statement. For example, &TIME or ®ION would not be valid names because both are keyword parameters on an EXEC statement. But &SPACE and &CLASS are acceptable names.
You can use the same symbolic parameter in a procedure as many times as you like. For example, you can use a symbolic parameter called &CLASS as the value for the SYSOUT parameter in all of the SYSOUT DD statements in a procedure. That way, you can be sure that all SYSOUT data sets are processed using the same output class. If you need to assign different classes to the SYSOUT data sets, however, you have to use more than one symbolic parameter.
The syntax for assigning values to symbolic parameters in a procedure
//[name] EXEC [PROC=]procedure-name,symbolic-parameter=value
Note:- A one- to seven-character name that is referenced by the procedure. The name can’t be a keyword parameter used by the EXEC statement.
A procedure that uses symbolic parameters in JCL.
//EMP3000 PROC
//EMP3010 EXEC PGM=EMP3000
//SYSOUT DD SYSOUT=*
//EMPMAST DD DSNAME=&HLQ..PAYROL.MAST.FILE,DISP=SHR
//EMPSEL DD DSNAME=&&EMPSEL,DISP=(NEW,PASS,DELETE),
// UNIT=SYSDA,SPACE=(CYL,(&SPACE))
//*
//SAL3030 EXEC PGM=SAL3030
//SYSOUT DD SYSOUT=*
//INVMAST DD DSNAME=&&SALREP,DISP=(OLD,DELETE,DELETE)
//INVSLST DD SYSOUT=*
The invoking EXEC statement (jcl proc override examples)
//STEPA01 EXEC INV3000,CLASS=M,HLQ=RCA2,SPACE='10,10'
Rules for coding symbolic parameters in JCL statements
- You can use the same symbolic parameter in a procedure as many times as you wish.
- Symbolic parameters can be mixed with text to form a final parameter value.
- If you want text to appear immediately after a symbolic parameter, you must code a period (.) as a delimiter between the symbolic parameter name and the text that follows it.
- If you want a period to appear immediately after a symbolic parameter, you have to code two periods in a row. The first one acts as a delimiter marking the end of the symbolic parameter and the second one becomes part of the JCL statement.
- To nullify the value of a symbolic parameter, you code the symbolic parameter’s name followed by an equals sign without a value.
SET Parameter in JCL with example.
The SET statement is another way to assign values to symbolic parameters. In contrast to a PROC statement that assigns default values or a procedure-invoking EXEC statement that provides runtime values, the SET statement lets you set the values of symbolic parameters at any point or time within your JCL. Be aware, however, that SET values are overridden by any values that are assigned in subsequent PROC or EXEC statements in the job.
The syntax for the SET statement
//[name] SET symbolic-parameter=value[,symbolic-parameter=value]…
Note - The name of a symbolic parameter you want to assign a value to.
//EMP3000 PROC
//EMP3010 EXEC PGM=EMP3000
//SYSOUT DD SYSOUT=*
//EMPMAST DD DSNAME=&HLQ..PAYROL.MAST.FILE,DISP=SHR
//EMPSEL DD DSNAME=&&EMPSEL,DISP=(NEW,PASS,DELETE),
// UNIT=SYSDA,SPACE=(CYL,(&SPACE))
//*
//SAL3030 EXEC PGM=SAL3030
//SYSOUT DD SYSOUT=*
//INVMAST DD DSNAME=&&SALREP,DISP=(OLD,DELETE,DELETE)
//INVSLST DD SYSOUT=*
The invoking EXEC statement (jcl proc override examples)
//RC01TN JOB (99992),'MAINFRAME',NOTIFY=MMTX01
// SET SPACE='10,5'
// SET HLQ=RCA2
//STEPA01 EXEC INV3000
Youtube: JCL Symbolic Parameters | JCL SET Statement | JCL Procedures | JCL Symbolic Parameters Examples JCL.
The JCL Symbolic Parameter tutorial is associated with a youtube video for good understanding. Please do watch this video and consider subscribing to our channel for more such tutorial video!
Summary.
As you code JCL, you’ll discover that there are many job steps…and series of job steps…that are used over and over in an installation, often by different programmers. That’s why OS/390 provides for procedures that can be stored in libraries and made available to any programmer on the system. With this facility, you can usually code just a few JCL statements to execute procedures that contain dozens or even hundreds of JCL statements. In fact, IBM supplies complex procedures that let you interface easily with software products like compilers, CICS, and DB2, and you’ll use them all the time. In addition, in most shops, you’ll create and use procedures that are specific to your installation.
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