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  • Modifying the type of lock for a data file
  • Effect of lock mode
  • Lock failure
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Stored procedures
Locks a data file and restricts the access to this data file for all other sites or applications. Then, the data file can be unlocked by <Source>.UnlockFile.
Several cases may occur after the call to <Source>.LockFile:
  • A file record is already locked by another application: the lock cannot be performed.
  • The data file is already locked by another application: the lock cannot be performed.
HErrorLock returns True if a lock problem occurs.
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
Example
// Lock the CUSTOMER data file
IF Customer.LockFile(hLockReadWrite) = False THEN
IF HErrorLock() = True THEN
Error("Operation not allowed")
END
END
// Process on data file ...
...
// Restore access to data file
Customer.UnlockFile()
Syntax
<Result> = <Source>.LockFile([<Lock>])
<Result>: Boolean
  • True if the lock was performed,
  • False if a problem occurred (the file is already locked for example). HError is used to identify the error.
<Source>: Type corresponding to the specified source
Name of data file used.
<Lock>: Optional integer constant
Used to define the type of lock performed on the data file:
hLockWrite
(default value)
Lock in write mode: the records found in the data file can be read by another application but cannot be modified by another application. No lock on the data file can be defined by another application.
hLockReadWriteLock in read/write: the records found in the data file cannot be read or modified by another application. No lock on the data file can be defined by another application.
hLockNoNo effect

Hyper File 5.5 <Lock> is ignored.
Remarks

Modifying the type of lock for a data file

To modify the type of lock applied to a data file, call <Source>.LockFile and specify the requested type of lock. There is no need to unlock the data file beforehand.

Effect of lock mode

<Source>.LockFile has no effect if the lock mode of the data file is set to hModeMono (see <Source>.Mode)

Lock failure

If the data file (or one of its records) is already locked, the lock request is retried H.NbRetry times (50 by default).
If the data file cannot be locked after H.NbRetry attempts, HErrorLock returns True.
Component: wd260hf.dll
Minimum version required
  • Version 25
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