The buffer returned by IXGQUERY (IXGQBUF) contains a version number. The meaning varies for DASD-only and coupling facility log streams, but the value is returned in field QBUF_STRUCT_VERSION_NUMBER for both. An alternate name for the field is QBUF_INSTANCE_VERSION_NUMBER.
For a DASD-only log stream, the version number is the time stamp in STCK format when the staging data set for the DASD-only log stream was created.
For a coupling facility log stream, the version number is the coupling facility list structure version number. This value shows the list structure version number of the coupling facility structure assigned to the log stream. A version number is assigned when a structure is initially allocated in the coupling facility and increases every time a structure is rebuilt or reallocated.