<Source>.LockFile (Function)

WINDEV, WEBDEV AND WINDEV MOBILE
ONLINE HELP

Version:

Home | Sign in | English

Modifying the type of lock for a data file

ErrorStatusModification

FilterIncludedBetween

MigrateLinkedCompositeKey

New WINDEV, WEBDEV, WINDEV Mobile 25 feature!

Modifying the type of lock for a data file
Effect of lock mode
Lock failure

WINDEV

WEBDEV

WINDEV Mobile

Others

See also

<Source>.LockFile (Function)

In french: <Source>.BloqueFichier

Not available with these kinds of connection

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.

This function can be used with HFSQL Client/Server data files.

Versions 17 and later

This function is now available for iPhone/iPad applications.

New in version 17

This function is now available for iPhone/iPad applications.

Versions 18 and later

This function is now available in Windows Store apps mode.

New in version 18

This function is now available in Windows Store apps mode.

Remark: From version 19, HFSQL is the new name of HyperFileSQL.

Versions 19 and later

This function is now available for Android applications.

This function is now available in Android Widget mode.

This function is now available for the Java applications.

New in version 19

This function is now available for Android applications.

This function is now available in Android Widget mode.

This function is now available for the Java applications.

This function is now available for Android applications.

This function is now available in Android Widget mode.

This function is now available for the Java applications.

Versions 21 and later

This function is now available in Universal Windows 10 App mode.

New in version 21

This function is now available in Universal Windows 10 App mode.

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.
hLockReadWrite Lock 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.
hLockNo No effect

<Lock> is ignored.
The management of locks is only performed on HFSQL Client/Server data files or data files handled by a native access. An HFSQL Mobile record cannot be locked. Indeed, the operating system of Pocket PC does not allow you to lock records.

The management of locks is performed on the HFSQL Client/Server data files only.

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 : wd250hf.dll