Use the BLDMFILECTL subcommand to define the build pointer segment
record data sets (S0nnnnn0) to create during the Build Index process. This
subcommand is effective only when the Build Index function runs in scan load mode
(BUILDMODE=SCANLOAD) or scan mode (BUILDMODE=SCAN).
Do not specify the BLDMFILECTL subcommand if you specify
BUILDDSNMASK keyword for the INDEXBLD command.
BLDMFILECTL
is an optional subcommand for the INDEXBLD command.