REXX ADDRESS TSO support requirements

If you want REXX ADDRESS TSO support, you must ensure that no REXX Language Processor Environment exists in your address space when you invoke IKJTSOEV. If you invoke IKJTSOEV from an address space that already contains a REXX Language Processor Environment and the REXX environment does not include the ADDRESS TSO host command environment, the REXX Language Processor Environment will continue to be available without ADDRESS TSO support.