@LOCK

This statement implements advisory locking of the currently SELECTed global partition. Advisory locking means that after an @LOCK other partitions can still read or write the global variables but if they issue an @LOCK themselves they will sleep until the global is unlocked with the @UNLOCK statement.

The @LOCK statement has no effect if:

• no global has been SELECTed
• the process already has an @LOCK statement in effect

Only implemented for process globals and not for memory mapped globals.

Example:

@LOCK
IF @lock_flag = 0 THEN @lock_flag = #PART
@UNLOCK

See also:

@UNLOCK