# Mail::Box::Locker::POSIX - lock a folder using kernel file-locking - perldoc - [phpMan]

## NAME
    [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown) - lock a folder using kernel file-locking

## INHERITANCE
     [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown)
       is a [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)
       is a [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

## SYNOPSIS
     See [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

## DESCRIPTION
    This locker object is created by the folder to get an exclusive lock on the file which contains
    the data using the kernel's POSIX facilities. This lock is created on a separate file-handle to
    the folder file, so not the handle which is reading.

    WARNING: Not all platforms support POSIX locking (via fcntl) and not always in the same way.
    This implementation does not use XS to access the structure of fcntl(): it is better to use the
    ::FcntlLock which does. No, this implementation "guesses" the location of the bytes.

    Extends "DESCRIPTION" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

## METHODS
    Extends "METHODS" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

### Constructors
    Extends "Constructors" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown)->new(%options)
         -Option    --Defined in       --Default
          expires     [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)  1 hour
          file        [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)  undef
          folder      [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)  <undef>
          log         [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)     'WARNINGS'
          method      [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)  POSIX
          posix_file                     <undef>
          timeout     [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)  10
          trace       [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)     'WARNINGS'

        expires => SECONDS
        file => FILENAME
        folder => FOLDER
        log => LEVEL
        method => STRING|CLASS|ARRAY
        posix_file => FILENAME
          Alternative name for "file", especially useful to avoid confusion when the multi-locker is
          used.

        timeout => SECONDS|'NOTIMEOUT'
        trace => LEVEL

### Attributes
    Extends "Attributes" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    $obj->expires( [SECONDS] )
        Inherited, see "Attributes" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

    $obj->timeout( [SECONDS] )
        Inherited, see "Attributes" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

### The Locker
    Extends "The Locker" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    $obj->filename( [$filename] )
        Inherited, see "The Locker" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

    $obj->folder( [$folder] )
        Inherited, see "The Locker" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

    $obj->name()
        Inherited, see "The Locker" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

### Locking
    Extends "Locking" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    $obj->hasLock()
        Inherited, see "Locking" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

    $obj->isLocked()
    $obj->lock()
    $obj->unlock()
        Inherited, see "Locking" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

### Error handling
    Extends "Error handling" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    $obj->AUTOLOAD()
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->addReport($object)
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
    [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown)->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->errors()
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->log( [$level, [$strings]] )
    [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown)->log( [$level, [$strings]] )
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->logPriority($level)
    [Mail::Box::Locker::POSIX](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker%3A%3APOSIX/markdown)->logPriority($level)
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->logSettings()
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->notImplemented()
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->report( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->reportAll( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->trace( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

    $obj->warnings()
        Inherited, see "Error handling" in [Mail::Reporter](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3AReporter/markdown)

### Cleanup
    Extends "Cleanup" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown).

    $obj->DESTROY()
        Inherited, see "Cleanup" in [Mail::Box::Locker](https://www.chedong.com/phpMan.php/perldoc/Mail%3A%3ABox%3A%3ALocker/markdown)

## DIAGNOSTICS
    Warning: Folder $folder already lockf'd
    Error: Package $package does not implement $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.

    Error: Unable to check lock file $filename for $folder: $!
        To check whether the filename is used to flock a folder, the file must be opened. Apparently
        this fails, which does not mean that the folder is locked neither that it is unlocked.

    Error: Unable to open POSIX lock file $filename for $folder: $!
        For POSIX style locking, a folder it must be opened, which does not succeed for the
        specified reason.

    Error: Will never get a POSIX lock at $filename for $folder: $!
        Tried to lock the folder, but it did not succeed. The error code received from the OS
        indicates that it will not succeed ever, so we do not need to try again.

## SEE ALSO
    This module is part of Mail-Box distribution version 3.010, built on July 18, 2023. Website:
    <http://perl.overmeer.net/CPAN/>

## LICENSE
    Copyrights 2001-2023 by [Mark Overmeer]. For other contributors see ChangeLog.

    This program is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself. See <http://dev.perl.org/licenses/>