5.4.5.5 Unlock Statement
Note
This section describes the implementation of MS-VBAL §5.4.5.5 Unlock Statement.
Syntax
| AST node | Instruction kind(s) | Notes |
|---|---|---|
| FileLockStatementNode | Simple |
Token: Unlock. StartRecord and EndRecord are named properties rather than positional inputs. |
Lock and Unlock share one AST node, FileLockStatementNode. Their record-range has three shapes, and
StartRecord and EndRecord are named because Lock #1, 5 and Lock #1, To 5 are different record ranges that
each carry one expression. See RD-VBAL §3.4.3 File Statements.
Runtime Semantics
Unlock takes the same record-range as Lock; see
RD-VBAL §5.4.5.4 Lock Statement.
Note
Not implemented. Lock and Unlock do not apply an OS-level lock.
MS-VBAL §5.4.5.4 Lock Statement
leaves applying an OS-level lock implementation-defined.
Implementation
Like every file statement, Unlock runs through the session's file-channel shim,
IFileChannels
(RD-VBAL §5.4.5 File Statements).
⏮️ RD-VBAL §5.4.5.4 Lock Statement | ⏭️ RD-VBAL §5.4.5.6 Line Input Statement