The unlock statement resets an execution lock, in the range 0 to 991, previously set with a lock statement.
unlock unlock lock.num.exp
| lock.num.exp | Specifies which execution lock (from 0 to 991) to reset. If not specified, all locks set by the program are unlocked. |
This conditionally sets execution lock 12 just before a segment of code that performs file retrieval and update. When complete, lock 12 is cleared by the unlock statement.
again: lock 12 else rqm; goto again read rec from file,ID else print ID:" not found"; rec = "X" write rec on file,ID unlock 12