STEPLIB is a private library specifies to the system that where program named in step EXEC exists.
STEPLIB can be placed anywhere in the step's JCL.
If the system can’t able to find the program in specified library with STEPLIB, it will start checking in system libraries.
STEPLIB libraries are of type PDS.
Each member in the PDS is a user written program and executable.
The STEPLIB DD statement is used to identify the program library to search first when attempting to locate programs executed during the job step execution.
More than one library can be concatenated on the STEPLIB.
If a STEPLIB DD is specified in a job that also has a JOBLIB, the STEPLIB takes precedence when searching for a program.
//STEPLIB DD DSN=private-library
Private-library is the library where the program executable paced.
STEPLIB can be coded in in-stream or cataloged procedures.
STEPLIB is used to specify the library where the currently executing program load resides.
STEPLIB is used to specify the load library for the specific step under the step it is coded.
Maximum 255 STEPLIBs can be coded in the JOB.
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JCL SPACE Parameter JCL JOBLIB