When the exit invokes the name generation function, the exit extracts the block ID from the XID passed by VTAM®. The exit searches the name generation table entries for an entry that corresponds to the block ID.

If the exit does not locate an entry in the table that corresponds to the XID, the exit returns control to VTAM with the X'80' bit in byte 0 of the build vector set to tell VTAM to deny the REQCONT (or the REQACTPU).

If the exit does locate an entry in the table that corresponds to the XID, the name generation function extracts data from the entry and uses it to construct names in the resource entry blocks in the build vector. When the exit returns control to VTAM, the X'80' bit in byte 0 of the build vector is reset.