Passing JCL symbols to the submitted job

When using the internal reader facility, the submitting job can be used to pass JCL symbols to the submitted job. These JCL symbols can be used in the JCL of the submitted job in the same way that JCL symbols created by a SET JCL statement are used. To pass JCL symbols to the submitted job using the internal reader, the list of symbols to pass must be defined for this internal reader using two methods:

Use the SYMBOLS= keyword on the DD statement that defines the internal reader (for static allocation). Refer to z/OS MVS JCL Reference for details.
Use the DALSYML text unit during dynamic allocation of the internal reader. Refer to z/OS MVS Programming: Authorized Assembler Services Guide for details.

The following symbols can be passed as JCL symbols to the submitted job:

JCL symbols that were previously made available to the job by an EXPORT JCL statement.
JES symbols that were dynamically created by the JES Symbol Service (IAZSYMBL). Refer to JES Symbol Service (IAZSYMBL) for details.

If dynamically-created JES symbols are passed by the submitting job, they must conform to the limitations of JCL symbols; refer to z/OS MVS JCL Reference for details. The special value SYMBOLS=* passes all symbols that are available to the current task and that conform to JCL limitations to the submitted job, which includes all JCL symbols and all usable JES symbols.

The list of JCL symbols to be passed by the internal reader specifies symbol names, but not their values. Symbol values are captured by the internal reader when the job is submitted. Applications can set or change symbol values before submitting a job so that different jobs submitted through the same internal reader will have the same set of symbols but different values.