Procedure for MVS/SP Version 4 and above libraries

Use this determination method when the source code is compiled against MVS/SP Version 4 and above macro libraries.

            L    10,X'10'               Load CVT pointer
            USING CVT,10
            TM   CVTDCB,CVTOSEXT        Is the OSLEVEL extension present?
            BNO  INVOKE_LIM             No, pre-MVS/SP Version 3 system
            TM   CVTOSLV0,CVTUCBSV      General methods supported?
            BNO  INVOKE_LIM             No, general methods unavailable
            UCBLOOK ........            Invoke general method
            B    BYPASS_LIM             Branch around limited method
INVOKE_LIM  DS 0H
            IOSLOOK                     Invoke limited method
BYPASS_LIM  DS 0H