Mail::Box::MH::Index - keep index files for messages.
 Mail::Box::MH::Index
   is a Mail::Reporter
 my $index = Mail::Box::MH::Index->new;
 $index->read(...)
 $index->write(...)
Message folders which store their data in one single file per
    message are very inefficient for producing subject overviews and for
    computing message threads. The
    "Mail::Box::MH::Index" object is able to
    store and read a the headers of a set of
    "Mail::Box::MH::Message" messages which
    are part of a single "Mail::Box::MH"
    folder in one file.
When the "Mail::Box::MH::Index"
    functionality is enabled by specifying Mail::Box::MH::new(keep_index) when
    opening a folder, the index file is automatically read. When the folder is
    closed, a new index file is created.
Special care is taken to avoid problems which occur when the user
    changes or removes message files without updating the index. If the index is
    not trustworthy it will not be used (costing some performance for the reader
    of the folder).
Extends "DESCRIPTION" in Mail::Reporter.
Extends "METHODS" in Mail::Reporter.
Extends "Constructors" in Mail::Reporter.
  - Mail::Box::MH::Index->new(%options)
- 
     -Option   --Defined in     --Default
  filename                    <required>
  head_type                   Mail::Message::Head::Subset
  head_wrap                   72
  log        Mail::Reporter   'WARNINGS'
  trace      Mail::Reporter   'WARNINGS'
    
  - filename =>
    FILENAME
- The FILENAME which is used to store the headers of all the e-mails for one
      folder. This must be an absolute pathname.
- head_type =>
    CLASS
- The type of headers which will be used to store header information when it
      is read from the index file. You can not be sure the index contains all
      header line (the mailbox may have been updated without updating the index)
      so this will usually be (an sub-class of)
    Mail::Message::Head::Subset.
- head_wrap =>
    INTEGER
- The preferred number of character in each header line.
- log => LEVEL
- trace => LEVEL
 
  - $obj->append($messages)
- Append $messages to the index file.
- $obj->filename()
- Returns the name of the index file.
- $obj->get($msgfile)
- Look if there is header info for the specified
      $msgfile. The filename represents one message in
      folder type which are organized as directory. This method will return an
      object of the new(head_type) as specified during creation of the index
      object, or "undef" if the information is
      not known or not trustworthy -i.e. the file size changed.
- $obj->read()
- Read the index file. The header objects can after this be requested with
      the get() method.
- $obj->write($messages)
- Write an index file containing the headers specified
      $messages (Mail::Message objects).
Extends "Error handling" in Mail::Reporter.
  - $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,
    $callback] )
- Mail::Box::MH::Index->defaultTrace(
    [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
- Inherited, see "Error handling" in Mail::Reporter
- $obj->errors()
- Inherited, see "Error handling" in Mail::Reporter
- $obj->log( [$level, [$strings]] )
- Mail::Box::MH::Index->log(
    [$level, [$strings]] )
- Inherited, see "Error handling" in Mail::Reporter
- $obj->logPriority($level)
- Mail::Box::MH::Index->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
Extends "Cleanup" in Mail::Reporter.
  - $obj->DESTROY()
- Inherited, see "Cleanup" in Mail::Reporter
  - 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.
This module is part of Mail-Box distribution version 3.011, built
    on April 18, 2025. Website: http://perl.overmeer.net/CPAN/
Copyrights 2001-2025 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/