Determining if the UCB macros (general methods) are available
Programs that need to determine if the UCB macros are installed
can use one of the following procedures. These procedures are provided
for programs that can also run on versions of MVS™ which do not support the UCB
macros.
Note: The UCB macros (general methods) are supported on MVS/SP Version
4 and above, as well as on MVS/SP Version 3 systems if the dynamic I/O
configuration compatibility APARs are installed.