=head1 NAME

Mail::Box::Locker::FcntlLock - lock a folder using File::FcntlLock

=head1 INHERITANCE

 Mail::Box::Locker::FcntlLock
   is a Mail::Box::Locker
   is a Mail::Reporter

=head1 SYNOPSIS

 See Mail::Box::Locker

=head1 DESCRIPTION

This locker object is uses File::FcntlLock, and was contributed by
Jim in Aus. It is close to L<Mail::Box::Locker::POSIX|Mail::Box::Locker::POSIX>, but does work
on more systems, for instance Darwin.

You will need to install File::FcntlLock separately: there is no
dependency to it by the MailBox distribution.

=head1 METHODS

=head2 Constructors

=over 4

=item Mail::Box::Locker::FcntlLock-E<gt>B<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  FcntlLock
  timeout  Mail::Box::Locker  10 seconds
  trace    Mail::Reporter   'WARNINGS'

=over 2

=item expires => SECONDS

=item file => FILENAME

=item folder => FOLDER

=item log => LEVEL

=item method => STRING|CLASS|ARRAY

=item timeout => SECONDS|'NOTIMEOUT'

=item trace => LEVEL

=back

=back

=head2 The Locker

=over 4

=item $obj-E<gt>B<filename>([FILENAME])

See L<Mail::Box::Locker/"The Locker">

=item $obj-E<gt>B<folder>([FOLDER])

See L<Mail::Box::Locker/"The Locker">

=item $obj-E<gt>B<name>()

See L<Mail::Box::Locker/"The Locker">

=back

=head2 Locking

=over 4

=item $obj-E<gt>B<hasLock>()

See L<Mail::Box::Locker/"Locking">

=item $obj-E<gt>B<isLocked>()

=item $obj-E<gt>B<lock>()

=item $obj-E<gt>B<unlock>()

See L<Mail::Box::Locker/"Locking">

=back

=head2 Error handling

=over 4

=item $obj-E<gt>B<AUTOLOAD>()

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<addReport>(OBJECT)

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

=item Mail::Box::Locker::FcntlLock-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<errors>()

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<log>([LEVEL [,STRINGS]])

=item Mail::Box::Locker::FcntlLock-E<gt>B<log>([LEVEL [,STRINGS]])

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<logPriority>(LEVEL)

=item Mail::Box::Locker::FcntlLock-E<gt>B<logPriority>(LEVEL)

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<logSettings>()

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<notImplemented>()

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<report>([LEVEL])

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<reportAll>([LEVEL])

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<trace>([LEVEL])

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<warnings>()

See L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

=over 4

=item $obj-E<gt>B<DESTROY>()

See L<Mail::Box::Locker/"Cleanup">

=item $obj-E<gt>B<inGlobalDestruction>()

See L<Mail::Reporter/"Cleanup">

=back

=head1 DIAGNOSTICS

=over 4

=item Warning: Folder $folder already lockf'd

=item 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.

=item 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.

=item Error: Unable to open FcntlLock lock file $filename for $folder: $!

For FcntlLock style locking, a folder it must be opened, which does not
succeed for the specified reason.

=item Error: Will never get a FcntlLock 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.

=back

=head1 SEE ALSO

This module is part of Mail-Box distribution version 2.106,
built on August 15, 2012. Website: F<http://perl.overmeer.net/mailbox/>

=head1 LICENSE

Copyrights 2001-2012 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 F<http://www.perl.com/perl/misc/Artistic.html>

