---
name: "Mail::Box::Locker::NFS"
section: "3pm"
platform: "linux"
package: "perl-mail-box"
version: "4.02-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Mail::Box::Locker::NFS"
---

# Mail::Box::Locker::NFS(3pm)

lock a folder with a separate file, NFS-safe

## NAME

Mail::Box::Locker::NFS - lock a folder with a separate file, NFS-safe

## INHERITANCE

```
 Mail::Box::Locker::NFS
   is a Mail::Box::Locker
   is a Mail::Reporter
```

## SYNOPSIS

```
  See Mail::Box::Locker
```

## DESCRIPTION

Like the `"::DotLock"` locker, but then in an NFS-safe fashion.  Over NFS, the creation of a file is not atomic.  The `"::DotLock"` locker depends on an atomic `"open"` system call, hence in not usable to lock a folder which accessed over NFS.  The `"::NFS"` locker is therefore more complicated (so therefore slower), but will work for NFS --and for local disks as well.

Extends "DESCRIPTION" in Mail::Box::Locker.

## METHODS

Extends "METHODS" in Mail::Box::Locker.

### Constructors

Extends "Constructors" in Mail::Box::Locker.

- $class-\>**new**(%options)

  Inherited, see "METHODS" in Mail::Box::Locker

  ```
   -Option --Defined in       --Default
    expires  Mail::Box::Locker  1 hour
    file     Mail::Box::Locker  undef
    folder   Mail::Box::Locker  <C<undef>>
    method   Mail::Box::Locker  'NFS'
    timeout  Mail::Box::Locker  10
  ```

  - expires =\> $seconds

    - file =\> $file

    - folder =\> $folder

    - method =\> $name\|CLASS\|\\@names

    - timeout =\> $seconds\|'NOTIMEOUT'

    ### Attributes

Extends "Attributes" in Mail::Box::Locker.

- $obj-\>**expires**( \[SECONDS\] )

  Inherited, see "Attributes" in Mail::Box::Locker

- $obj-\>**filename**( \[$filename\] )

  Inherited, see "Attributes" in Mail::Box::Locker

- $obj-\>**folder**( \[$folder\] )

  Inherited, see "Attributes" in Mail::Box::Locker

- $obj-\>**name**()

  Inherited, see "Attributes" in Mail::Box::Locker

- $obj-\>**timeout**( \[SECONDS\] )

  Inherited, see "Attributes" in Mail::Box::Locker

### Locking

Extends "Locking" in Mail::Box::Locker.

- $obj-\>**hasLock**()

  Inherited, see "Locking" in Mail::Box::Locker

- $obj-\>**isLocked**()

  Inherited, see "Locking" in Mail::Box::Locker

- $obj-\>**lock**()

  Inherited, see "Locking" in Mail::Box::Locker

- $obj-\>**unlock**()

  Inherited, see "Locking" in Mail::Box::Locker

### Error handling

Extends "Error handling" in Mail::Box::Locker.

- $obj-\>**AUTOLOAD**()

  Inherited, see "Error handling" in Mail::Reporter

- $obj-\>**notImplemented**()

  Inherited, see "Error handling" in Mail::Reporter

### Cleanup

Extends "Cleanup" in Mail::Box::Locker.

- $obj-\>**DESTROY**()

  Inherited, see "Cleanup" in Mail::Box::Locker

## DIAGNOSTICS

- Error: class $package does not implement method $method.

  Fatal error: the specific `$package` (or one of its superclasses) does not implement this method where it should. This message means that some other related classes do implement this method however the class at hand does not.  Probably you should investigate this and probably inform the author of the package. Cast by `notImplemented()`

- Fault: couldn't remove lockfile $file: $!

  Cast by `unlock()`

- Warning: folder $name already locked over NFS.

  Do not try to lock the folder when the application already has the lock: it will give you dead-locks. Cast by `lock()`

- Warning: removed expired lockfile $file.

  A lock `$file` was found which was older than the expiration period as specified with new(timeout).  The lock file was successfully removed. Cast by `lock()`

- Fault: unable to remove expired lockfile $file: $!

  A lock file was found which was older than the expiration period as specified with the new(timeout) option.  It is impossible to remove that lock file, so we need to wait until it vanishes by some external cause. Cast by `lock()`

## SEE ALSO

This module is part of Mail-Box version 4.02, built on April 10, 2026. Website: *http://perl.overmeer.net/CPAN/*

## LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2026 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.