# Mail::Box::Locker::POSIX - phpMan

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

## INHERITANCE
     [Mail::Box::Locker::POSIX]
       is a [Mail::Box::Locker]
       is a [Mail::Reporter]

## SYNOPSIS
     See [Mail::Box::Locker]

## 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].

## METHODS
    Extends "METHODS" in [Mail::Box::Locker].

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

    [Mail::Box::Locker::POSIX]->new(%options)
         -Option    --Defined in       --Default
          expires     [Mail::Box::Locker]  1 hour
          file        [Mail::Box::Locker]  undef
          folder      [Mail::Box::Locker]  <undef>
          log         [Mail::Reporter]     'WARNINGS'
          method      [Mail::Box::Locker]  POSIX
          posix_file                     <undef>
          timeout     [Mail::Box::Locker]  10
          trace       [Mail::Reporter]     '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].

    $obj->expires( [SECONDS] )
        Inherited, see "Attributes" in [Mail::Box::Locker]

    $obj->timeout( [SECONDS] )
        Inherited, see "Attributes" in [Mail::Box::Locker]

  The Locker
    Extends "The Locker" in [Mail::Box::Locker].

    $obj->filename( [$filename] )
        Inherited, see "The Locker" in [Mail::Box::Locker]

    $obj->folder( [$folder] )
        Inherited, see "The Locker" in [Mail::Box::Locker]

    $obj->name()
        Inherited, see "The Locker" in [Mail::Box::Locker]

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

    $obj->hasLock()
        Inherited, see "Locking" in [Mail::Box::Locker]

    $obj->isLocked()
    $obj->lock()
    $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]

    $obj->addReport($object)
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level,
    $callback] )
    [Mail::Box::Locker::POSIX]->defaultTrace( [$level]|[$loglevel,
    $tracelevel]|[$level, $callback] )
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->errors()
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->log( [$level, [$strings]] )
    [Mail::Box::Locker::POSIX]->log( [$level, [$strings]] )
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->logPriority($level)
    [Mail::Box::Locker::POSIX]->logPriority($level)
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->logSettings()
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->notImplemented()
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->report( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->reportAll( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->trace( [$level] )
        Inherited, see "Error handling" in [Mail::Reporter]

    $obj->warnings()
        Inherited, see "Error handling" in [Mail::Reporter]

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

    $obj->DESTROY()
        Inherited, see "Cleanup" in [Mail::Box::Locker]

## 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 3.009, built on
    August 18, 2020. Website: <http://perl.overmeer.net/CPAN/>

## LICENSE
    Copyrights 2001-2020 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/>