Do not attempt to modify checkpointed data from this exit.
See JES2 exit usage limitations for a listing of specific instances when
this exit will be invoked or not invoked.
Exit 6 must be MVS™ reentrant. See “Reentrant Code
Considerations” in "Writing
an exit routine" for more information.
Do not alter any fields in the $JQE. The changes will not be
successful because you are in the subtask environment.
Do not attempt to control the processing of the MVS converter
by changing the C/I text at Exit 6. The converter does not examine
the C/I text returned from the exit to determine what changes have
been made. For example, you cannot use this exit to execute a procedure
other than the one initially named on the EXEC statement, nor can
you use this exit to control the printing of JCL statement images
by altering the MSGLEVEL parameter on the JOB statement.