The LOCK file statement causes the specified file to be closed.

<lock file statement>

── LOCK ── ( ──<file designator>─┬────────────────────┬─ ) ────────────┤
                                 └─ , ──<lock option>─┘

<lock option>

──┬─ CRUNCH ─┬─────────────────────────────────────────────────────────┤
  └─ * ──────┘

The LOCK file statement cannot be used as a function.