Note: Since this is an ISAM function, all locks can be released with LockISAM(ctFREE).
With this option, a read lock will be placed on each record. This lock prevents other users from acquiring a write (update) lock on this record. If a lock cannot be obtained on a particular record then it will not be read. The PKEYREQ value bavail specifies the number of records that have been locked successfully. If bavail is less than btotal, not all records were locked.
Similar to BAT_LOK_RED, except that a write (update) lock will be acquired.
No locks will be acquired.