{
    "content": [
        {
            "type": "text",
            "text": "# Mail::Box::MH (info)\n\n## NAME\n\nMail::Box::MH - handle MH folders\n\n## SYNOPSIS\n\nuse Mail::Box::MH;\nmy $folder = new Mail::Box::MH folder => $ENV{MAIL}, ...;\n\n## DESCRIPTION\n\nThis documentation describes how MH mailboxes work, and what you can do\nwith the MH folder object \"Mail::Box::MH\".\n\n## Sections\n\n- **Mail::Box::MH(3pm)    User Contributed Perl Documentation   Mail::Box::MH(3pm)**\n- **NAME**\n- **INHERITANCE**\n- **SYNOPSIS**\n- **DESCRIPTION**\n- **OVERLOADED**\n- **METHODS**\n- **DETAILS**\n- **DIAGNOSTICS**\n- **SEE ALSO**\n- **LICENSE**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n"
        }
    ],
    "structuredContent": {
        "command": "Mail::Box::MH",
        "section": "",
        "mode": "info",
        "summary": "Mail::Box::MH - handle MH folders",
        "synopsis": "use Mail::Box::MH;\nmy $folder = new Mail::Box::MH folder => $ENV{MAIL}, ...;",
        "tldr_summary": null,
        "tldr_examples": [],
        "tldr_source": null,
        "flags": [],
        "examples": [],
        "see_also": [],
        "section_outline": [
            {
                "name": "Mail::Box::MH(3pm)    User Contributed Perl Documentation   Mail::Box::MH(3pm)",
                "lines": 1,
                "subsections": []
            },
            {
                "name": "NAME",
                "lines": 2,
                "subsections": []
            },
            {
                "name": "INHERITANCE",
                "lines": 5,
                "subsections": []
            },
            {
                "name": "SYNOPSIS",
                "lines": 3,
                "subsections": []
            },
            {
                "name": "DESCRIPTION",
                "lines": 5,
                "subsections": []
            },
            {
                "name": "OVERLOADED",
                "lines": 11,
                "subsections": []
            },
            {
                "name": "METHODS",
                "lines": 361,
                "subsections": []
            },
            {
                "name": "DETAILS",
                "lines": 59,
                "subsections": []
            },
            {
                "name": "DIAGNOSTICS",
                "lines": 81,
                "subsections": []
            },
            {
                "name": "SEE ALSO",
                "lines": 3,
                "subsections": []
            },
            {
                "name": "LICENSE",
                "lines": 7,
                "subsections": []
            }
        ],
        "sections": {
            "Mail::Box::MH(3pm)    User Contributed Perl Documentation   Mail::Box::MH(3pm)": {
                "content": "",
                "subsections": []
            },
            "NAME": {
                "content": "Mail::Box::MH - handle MH folders\n",
                "subsections": []
            },
            "INHERITANCE": {
                "content": "Mail::Box::MH\nis a Mail::Box::Dir\nis a Mail::Box\nis a Mail::Reporter\n",
                "subsections": []
            },
            "SYNOPSIS": {
                "content": "use Mail::Box::MH;\nmy $folder = new Mail::Box::MH folder => $ENV{MAIL}, ...;\n",
                "subsections": []
            },
            "DESCRIPTION": {
                "content": "This documentation describes how MH mailboxes work, and what you can do\nwith the MH folder object \"Mail::Box::MH\".\n\nExtends \"DESCRIPTION\" in Mail::Box::Dir.\n",
                "subsections": []
            },
            "OVERLOADED": {
                "content": "Extends \"OVERLOADED\" in Mail::Box::Dir.\n\noverload: \"\"\nInherited, see \"OVERLOADED\" in Mail::Box\n\noverload: @{}\nInherited, see \"OVERLOADED\" in Mail::Box\n\noverload: cmp\nInherited, see \"OVERLOADED\" in Mail::Box\n",
                "subsections": []
            },
            "METHODS": {
                "content": "Extends \"METHODS\" in Mail::Box::Dir.\n\nConstructors\nExtends \"Constructors\" in Mail::Box::Dir.\n\nMail::Box::MH->new(%options)\n-Option           --Defined in     --Default\naccess             Mail::Box        'r'\nbodydelayedtype  Mail::Box        Mail::Message::Body::Delayed\nbodytype          Mail::Box        Mail::Message::Body::Lines\ncoerceoptions     Mail::Box        []\ncreate             Mail::Box        <false>\ndirectory          Mail::Box::Dir   <derived from folder name>\nextract            Mail::Box        10240\nfieldtype         Mail::Box        undef\nfixheaders        Mail::Box        <false>\nfolder             Mail::Box        $ENV{MAIL}\nfolderdir          Mail::Box        $ENV{HOME}/.mh\nheaddelayedtype  Mail::Box        Mail::Message::Head::Delayed\nheadtype          Mail::Box        Mail::Message::Head::Complete\nindex                               undef\nindexfilename                      <foldername>/.index\nindextype                          Mail::Box::MH::Index\nkeepdups          Mail::Box        <false>\nkeepindex                          0\nlabels                              undef\nlabelsfilename                     <foldername>/.mhsequence\nlabelstype                         Mail::Box::MH::Labels\nlockfile          Mail::Box        <indexfile>\nlocktimeout       Mail::Box        1 hour\nlocktype          Mail::Box        Mail::Box::Locker::DotLock\nlockwait          Mail::Box        10 seconds\nlocker             Mail::Box        undef\nlog                Mail::Reporter   'WARNINGS'\nmanager            Mail::Box        undef\nmessagetype       Mail::Box        <folder-class>::Message\nmultiparttype     Mail::Box        Mail::Message::Body::Multipart\nremovewhenempty  Mail::Box        <true>\nsaveonexit       Mail::Box        <true>\ntrace              Mail::Reporter   'WARNINGS'\ntrusted            Mail::Box        <depends on folder location>\n\naccess => MODE\nbodydelayedtype => CLASS\nbodytype => CLASS|CODE\ncoerceoptions => ARRAY\ncreate => BOOLEAN\ndirectory => DIRECTORY\nextract => INTEGER | CODE | METHOD | 'LAZY'|'ALWAYS'\nfieldtype => CLASS\nfixheaders => BOOLEAN\nfolder => FOLDERNAME\nfolderdir => DIRECTORY\nheaddelayedtype => CLASS\nheadtype => CLASS\nindex => OBJECT\nYou may specify an OBJECT of a type which extends\nMail::Box::MH::Index (at least implements a \"get()\" method), as\nalternative for an index file reader as created by\n\"Mail::Box::MH\".\n\nindexfilename => FILENAME\nThe FILENAME which is used in each directory to store the headers\nof all mails. The filename shall not contain a directory path.\n(e.g. Do not use \"/usr/people/jan/.index\", nor \"subdir/.index\",\nbut say \".index\".)\n\nindextype => CLASS\nkeepdups => BOOLEAN\nkeepindex => BOOLEAN\nKeep an index file of the specified mailbox, one file per\ndirectory.  Using an index file will speed up things\nconsiderably, because it avoids reading all the message files the\nmoment that you open the folder.  When you open a folder, you can\nuse the index file to retrieve information such as the subject of\neach message, instead of having to read possibly thousands of\nmessages.\n\nlabels => OBJECT\nYou may specify an OBJECT of a type which extends\nMail::Box::MH::Labels (at least implements the \"get()\" method),\nas alternative for labels file reader as created by\n\"Mail::Box::MH\".\n\nlabelsfilename => FILENAME\nIn MH-folders, messages can be labeled, for instance based on the\nsender or whether it is read or not.  This status is kept in a\nfile which is usually called \".mhsequences\", but that name can\nbe overruled with this flag.\n\nlabelstype => CLASS\nlockfile => FILENAME\nlocktimeout => SECONDS\nlocktype => CLASS|STRING|ARRAY\nlockwait => SECONDS\nlocker => OBJECT\nlog => LEVEL\nmanager => MANAGER\nmessagetype => CLASS\nmultiparttype => CLASS\nremovewhenempty => BOOLEAN\nsaveonexit => BOOLEAN\ntrace => LEVEL\ntrusted => BOOLEAN\n\nThe folder\nExtends \"The folder\" in Mail::Box::Dir.\n\n$obj->addMessage($message, %options)\nInherited, see \"The folder\" in Mail::Box\n\n$obj->addMessages(@messages)\nInherited, see \"The folder\" in Mail::Box\n\nMail::Box::MH->appendMessages(%options)\nAppend a message to a folder which is not open.\n\n-Option  --Defined in     --Default\nfolder    Mail::Box        <required>\nmessage   Mail::Box        undef\nmessages  Mail::Box        undef\nshare     Mail::Box        <false>\n\nfolder => FOLDERNAME\nmessage => MESSAGE\nmessages => ARRAY-OF-MESSAGES\nshare => BOOLEAN\n$obj->close(%options)\nInherited, see \"The folder\" in Mail::Box\n\n$obj->copyTo($folder, %options)\nInherited, see \"The folder\" in Mail::Box\n\n$obj->delete(%options)\nInherited, see \"The folder\" in Mail::Box\n\n$obj->directory()\nInherited, see \"The folder\" in Mail::Box::Dir\n\n$obj->folderdir( [$directory] )\nInherited, see \"The folder\" in Mail::Box\n\n$obj->name()\nInherited, see \"The folder\" in Mail::Box\n\n$obj->organization()\nInherited, see \"The folder\" in Mail::Box\n\n$obj->size()\nInherited, see \"The folder\" in Mail::Box\n\n$obj->type()\nInherited, see \"The folder\" in Mail::Box\n\n$obj->update(%options)\nInherited, see \"The folder\" in Mail::Box\n\n$obj->url()\nInherited, see \"The folder\" in Mail::Box\n\nFolder flags\nExtends \"Folder flags\" in Mail::Box::Dir.\n\n$obj->access()\nInherited, see \"Folder flags\" in Mail::Box\n\n$obj->isModified()\nInherited, see \"Folder flags\" in Mail::Box\n\n$obj->modified( [BOOLEAN] )\nInherited, see \"Folder flags\" in Mail::Box\n\n$obj->writable()\nInherited, see \"Folder flags\" in Mail::Box\n\nThe messages\nExtends \"The messages\" in Mail::Box::Dir.\n\n$obj->current( [$number|$message|$messageid] )\nInherited, see \"The messages\" in Mail::Box\n\n$obj->find($messageid)\nInherited, see \"The messages\" in Mail::Box\n\n$obj->findFirstLabeled( $label, [BOOLEAN, [$msgs]] )\nInherited, see \"The messages\" in Mail::Box\n\n$obj->message( $index, [$message] )\nInherited, see \"The messages\" in Mail::Box\n\n$obj->messageId( $messageid, [$message] )\nInherited, see \"The messages\" in Mail::Box\n\n$obj->messageIds()\nInherited, see \"The messages\" in Mail::Box\n\n$obj->messages( <'ALL'|$range|'ACTIVE'|'DELETED'|$label|\n!$label|$filter> )\nInherited, see \"The messages\" in Mail::Box\n\n$obj->nrMessages(%options)\nInherited, see \"The messages\" in Mail::Box\n\n$obj->scanForMessages($message, $messageids, $timespan, $window)\nInherited, see \"The messages\" in Mail::Box\n\nSub-folders\nExtends \"Sub-folders\" in Mail::Box::Dir.\n\n$obj->listSubFolders(%options)\nMail::Box::MH->listSubFolders(%options)\nInherited, see \"Sub-folders\" in Mail::Box\n\n$obj->nameOfSubFolder( $subname, [$parentname] )\nMail::Box::MH->nameOfSubFolder( $subname, [$parentname] )\nInherited, see \"Sub-folders\" in Mail::Box\n\n$obj->openRelatedFolder(%options)\nInherited, see \"Sub-folders\" in Mail::Box\n\n$obj->openSubFolder($subname, %options)\nInherited, see \"Sub-folders\" in Mail::Box\n\n$obj->topFolderWithMessages()\nMail::Box::MH->topFolderWithMessages()\nInherited, see \"Sub-folders\" in Mail::Box\n\nInternals\nExtends \"Internals\" in Mail::Box::Dir.\n\n$obj->coerce($message, %options)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->create($foldername, %options)\nMail::Box::MH->create($foldername, %options)\n-Option   --Defined in--Default\nfolderdir  Mail::Box   undef\n\nfolderdir => DIRECTORY\n$obj->determineBodyType($message, $head)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->folderToDirectory($foldername, $folderdir)\nInherited, see \"Internals\" in Mail::Box::Dir\n\nMail::Box::MH->foundIn( [$foldername], %options )\nInherited, see \"Internals\" in Mail::Box\n\n$obj->highestMessageNumber()\nReturns the highest number which is used in the folder to store a\nfile.  This method may be called when the folder is read (then this\nnumber can be derived without file-system access), but also when\nthe folder is not read (yet).\n\n$obj->index()\nCreate a index reader/writer object.\n\n$obj->labels()\nCreate a label reader/writer object.\n\n$obj->lineSeparator( [<STRING|'CR'|'LF'|'CRLF'>] )\nInherited, see \"Internals\" in Mail::Box\n\n$obj->locker()\nInherited, see \"Internals\" in Mail::Box\n\n$obj->messageInFile($filename)\nInherited, see \"Internals\" in Mail::Box::Dir\n\n$obj->read(%options)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->readMessageFilenames($directory)\nInherited, see \"Internals\" in Mail::Box::Dir\n\n$obj->readMessages(%options)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->storeMessage($message)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->toBeThreaded($messages)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->toBeUnthreaded($messages)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->updateMessages(%options)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->write(%options)\nInherited, see \"Internals\" in Mail::Box\n\n$obj->writeMessages(%options)\n-Option  --Defined in     --Default\nmessages  Mail::Box        <required>\nrenumber                   <true>\n\nmessages => ARRAY\nrenumber => BOOLEAN\nPermit renumbering of message.  By default this is true, but for\nsome unknown reason, you may be thinking that messages should not\nbe renumbered.\n\nOther methods\nExtends \"Other methods\" in Mail::Box::Dir.\n\n$obj->timespan2seconds($time)\nMail::Box::MH->timespan2seconds($time)\nInherited, see \"Other methods\" in Mail::Box\n\nError handling\nExtends \"Error handling\" in Mail::Box::Dir.\n\n$obj->AUTOLOAD()\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->addReport($object)\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level,\n$callback] )\nMail::Box::MH->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level,\n$callback] )\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->errors()\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->log( [$level, [$strings]] )\nMail::Box::MH->log( [$level, [$strings]] )\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->logPriority($level)\nMail::Box::MH->logPriority($level)\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->logSettings()\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->notImplemented()\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->report( [$level] )\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->reportAll( [$level] )\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->trace( [$level] )\nInherited, see \"Error handling\" in Mail::Reporter\n\n$obj->warnings()\nInherited, see \"Error handling\" in Mail::Reporter\n\nCleanup\nExtends \"Cleanup\" in Mail::Box::Dir.\n\n$obj->DESTROY()\nInherited, see \"Cleanup\" in Mail::Box\n",
                "subsections": []
            },
            "DETAILS": {
                "content": "Extends \"DETAILS\" in Mail::Box::Dir.\n\nDifferent kinds of folders\nExtends \"Different kinds of folders\" in Mail::Box::Dir.\n\nAvailable folder types\nExtends \"Available folder types\" in Mail::Box::Dir.\n\nFolder class implementation\nExtends \"Folder class implementation\" in Mail::Box::Dir.\n\nHow MH folders work\nMH-type folders use a directory to store the messages of one folder.\nEach message is stored in a separate file.  This seems useful, because\nchanges in a folder change only a few of these small files, in contrast\nwith file-based folders where changes in a folder cause rewrites of\nhuge folder files.\n\nHowever, MH-based folders perform very bad if you need header\ninformation of all messages.  For instance, if you want to have full\nknowledge about all message-threads (see Mail::Box::Thread::Manager) in\nthe folder, it requires to read all header lines in all message files.\nAnd usually, reading your messages in threads is desired.\n\nSo, each message is written in a separate file.  The filenames are\nnumbers, which count from 1.  Next to these message files, a directory\nmay contain a file named \".mhsequences\", storing labels which relate\nto the messages.  Furthermore, a folder-directory may contain sub-\ndirectories, which are seen as sub-folders.\n\nThis implementation\nThis implementation supports the \".mh-sequences\" file and sub-folders.\nNext to this, considerable effort it made to avoid reading each\nmessage-file.  This should boost performance of the MailBox\ndistribution over other Perl-modules which are able to read folders.\n\nFolder types which store their messages each in one file, together in\none directory, are bad for performance.  Consider that you want to know\nthe subjects of all messages, while browser through a folder with your\nmail-reading client.  This would cause all message-files to be read.\n\nMail::Box::MH has two ways to try improve performance.  You can use an\nindex-file, and use on delay-loading.  The combination performs even\nbetter.  Both are explained in the next sections.\n\nAn index-file\nIf you specify new(keepindex), then all header-lines of all messages\nfrom the folder which have been read once, will also be written into\none dedicated index-file (one file per folder).  The default filename\nis \".index\"\n\nHowever, index-files are not supported by any other reader which\nsupports MH (as far as I know).  If you read the folders with such I\nclient, it will not cause unrecoverable conflicts with this index-file,\nbut at most be bad for performance.\n\nIf you do not (want to) use an index-file, then delay-loading may save\nyour day.\n",
                "subsections": []
            },
            "DIAGNOSTICS": {
                "content": "Error: Cannot append message without lock on $folder.\nIt is impossible to append one or more messages to the folder which\nis not opened, because locking it fails.  The folder may be in use\nby an other application, or you may need to specify some lock\nrelated options (see new()).\n\nError: Cannot create MH folder $name: $!\nFor some reason, it is impossible to create the folder.  Check the\npermissions and the name of the folder.  Does the path to the\ndirectory to be created exist?\n\nError: Cannot write folder $name without lock.\nIt is impossible to get a lock on the folder, which means that the\nchanges can not be made.  You may need to tune the lock related\noptions which are available at folder creation.\n\nWarning: Changes not written to read-only folder $self.\nYou have opened the folder read-only --which is the default set by\nnew(access)--, made modifications, and now want to close it.  Set\nclose(force) if you want to overrule the access mode, or close the\nfolder with close(write) set to \"NEVER\".\n\nError: Copying failed for one message.\nFor some reason, for instance disc full, removed by external\nprocess, or read-protection, it is impossible to copy one of the\nmessages.  Copying will proceed for the other messages.\n\nError: Destination folder $name is not writable.\nThe folder where the messages are copied to is not opened with\nwrite access (see new(access)).  This has no relation with write\npermission to the folder which is controlled by your operating\nsystem.\n\nWarning: Different messages with id $msgid\nThe message id is discovered more than once within the same folder,\nbut the content of the message seems to be different.  This should\nnot be possible: each message must be unique.\n\nError: Folder $name is opened read-only\nYou can not write to this folder unless you have opened the folder\nto write or append with new(access), or the \"force\" option is set\ntrue.\n\nError: Folder $name not deleted: not writable.\nThe folder must be opened with write access via new(access),\notherwise removing it will be refused.  So, you may have write-\naccess according to the operating system, but that will not\nautomatically mean that this \"delete\" method permits you to.  The\nreverse remark is valid as well.\n\nError: Invalid timespan '$timespan' specified.\nThe string does not follow the strict rules of the time span syntax\nwhich is permitted as parameter.\n\nWarning: Message-id '$msgid' does not contain a domain.\nAccording to the RFCs, message-ids need to contain a unique random\npart, then an \"@\", and then a domain name.  This is made to avoid\nthe creation of two messages with the same id.  The warning emerges\nwhen the \"@\" is missing from the string.\n\nError: Package $package does not implement $method.\nFatal error: the specific package (or one of its superclasses) does\nnot implement this method where it should. This message means that\nsome other related classes do implement this method however the\nclass at hand does not.  Probably you should investigate this and\nprobably inform the author of the package.\n\nError: Unable to create subfolder $name of $folder.\nThe copy includes the subfolders, but for some reason it was not\npossible to copy one of these.  Copying will proceed for all other\nsub-folders.\n\nError: Unable to write message for $folder to $filename: $!\nThe new message could not be written to its new file, for the\nspecific reason.\n\nError: Writing folder $name failed\nFor some reason (you probably got more error messages about this\nproblem) it is impossible to write the folder, although you should\nbecause there were changes made.\n",
                "subsections": []
            },
            "SEE ALSO": {
                "content": "This module is part of Mail-Box distribution version 3.009, built on\nAugust 18, 2020. Website: http://perl.overmeer.net/CPAN/\n",
                "subsections": []
            },
            "LICENSE": {
                "content": "Copyrights 2001-2020 by [Mark Overmeer]. For other contributors see\nChangeLog.\n\nThis program is free software; you can redistribute it and/or modify it\nunder the same terms as Perl itself.  See http://dev.perl.org/licenses/\n\nperl v5.30.3                      2020-08-20                Mail::Box::MH(3pm)",
                "subsections": []
            }
        }
    }
}