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FileTools

  

Unlock

  

release a file lock

 

Calling Sequence

Parameters

Description

Examples

Calling Sequence

Unlock(file, opt1, opt2, ...)

Parameters

file

-

filename or the file descriptor of a locked file

opt1, opt2, ...

-

(optional) arguments

Description

• 

The Unlock(file) command releases a file lock for file.  With no optional arguments, the exclusive lock for the entire file is released.

• 

The optional arguments passed to Unlock must match those given to Lock when the lock was acquired.

• 

If opt1, opt2, ... is bytes=low..high, then the bytes in file position low to high in file are unlocked.  If relative is also specified, then low and high are considered relative to the current file position.   The bytes range must match a range given to a call to Lock.

• 

The Unlock command does not return anything.  If an error occurs, an exception  is raised.

• 

For more information about file locking, see the Lock help page.

• 

Locks on a file are released when the file is closed.  As all files are closed on exit from Maple, all file locks are released when Maple exits.  It is possible that these file locks will not be removed immediately when Maple exits.  Therefore, if you depend on files being immediately available after Maple exits, they must be explicitly unlocked.

• 

On UNIX systems it is not necessary that the bytes range be the range of a Lock call.  All the bytes in the specified range are unlocked, assuming they are of matching type.

Examples

FileTools[Text][Open]testFile:

FileTools[Lock]testFile,bytes=10..20

true

(1)

FileTools[Unlock]testFile,bytes=10..20

See Also

FileTools

FileTools[IsLockable]

FileTools[Text][Open]

IO_errors

iostatus

 


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