--- name: "Mail::Message::Head::ListGroup" section: "3pm" platform: "linux" package: "perl-mail-message" version: "4.05-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/Mail::Message::Head::ListGroup" --- # Mail::Message::Head::ListGroup(3pm) mailinglist related header fields ## NAME Mail::Message::Head::ListGroup - mailinglist related header fields ## INHERITANCE ``` Mail::Message::Head::ListGroup is a Mail::Message::Head::FieldGroup is a Mail::Reporter ``` ## SYNOPSIS ``` my $lg = Mail::Message::Head::ListGroup->new(head => $head, ...); $head->addListGroup($lg); my $lg = $head->addListGroup(...); $lg->delete; ``` ## DESCRIPTION A *list group* is a set of header fields which are added by mailing-list managing software. This class knowns various details about that software. The knowledge and test messages which are used to initially implement this module is taken from Mail::ListDetector, written by Michael Stevens *mailto:michael@etla.org*. The logic is redesigned to add flexibility and use the powerful MailBox features. Extends "DESCRIPTION" in Mail::Message::Head::FieldGroup. ## METHODS Extends "METHODS" in Mail::Message::Head::FieldGroup. ### Constructors Extends "Constructors" in Mail::Message::Head::FieldGroup. - $obj-\>**address**() Returns a Mail::Message::Field::Address object (or `"undef"`) which defines the posting address of the mailing list. - $obj-\>**clone**() Inherited, see "Constructors" in Mail::Message::Head::FieldGroup - $obj-\>**from**($head\|$message) Create a `"Mail::Message::Head::ListGroup"` based in the specified `$message` or message `$head`. Improves base, see "Constructors" in Mail::Message::Head::FieldGroup - $any-\>**implementedTypes**() Inherited, see "Constructors" in Mail::Message::Head::FieldGroup - $obj-\>**listname**() Returns the name of the mailing list, which is usually a part of the e-mail address which is used to post the messages to. - $class-\>**new**($fields, %options) Construct an object which maintains one set of mailing list headers Improves base, see "Constructors" in Mail::Message::Head::FieldGroup ``` -Option --Defined in --Default address undef head Mail::Message::Head::FieldGroup undef listname rfc undef software Mail::Message::Head::FieldGroup undef type Mail::Message::Head::FieldGroup undef version Mail::Message::Head::FieldGroup undef ``` - address =\> STRING\|OBJECT Address of the mailing list, which may be specified as STRING or e-mail containing object (a Mail::Address or Mail::Identity. In any case, the data is converted into a Mail::Identity. - head =\> $head - listname =\> STRING A short textual representation of the mailing-list. - rfc =\> 'rfc2919'\|'rfc2369' Defines the mailing list software follows an rfc. - software =\> STRING - type =\> STRING - version =\> STRING - $obj-\>**rfc**() When the mailing list software follows the guidelines of one of the dedicated RFCs, then this will be returned otherwise `"undef"`. The return values can be `"rfc2919"`, `"rfc2369"`, or `"undef"`. ### Attributes Extends "Attributes" in Mail::Message::Head::FieldGroup. ### The header Extends "The header" in Mail::Message::Head::FieldGroup. - $obj-\>**add**( \<$field, $value\> \| $object ) Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**addFields**( \[$fieldnames\] ) Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**attach**($head) Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**delete**() Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**fieldNames**() Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**fields**() Inherited, see "The header" in Mail::Message::Head::FieldGroup - $obj-\>**head**() Inherited, see "The header" in Mail::Message::Head::FieldGroup ### Access to the header Extends "Access to the header" in Mail::Message::Head::FieldGroup. - $any-\>**isListGroupFieldName**($name) - $obj-\>**software**() Inherited, see "Access to the header" in Mail::Message::Head::FieldGroup - $obj-\>**type**() Inherited, see "Access to the header" in Mail::Message::Head::FieldGroup - $obj-\>**version**() Inherited, see "Access to the header" in Mail::Message::Head::FieldGroup ### Internals Extends "Internals" in Mail::Message::Head::FieldGroup. - $obj-\>**collectFields**() Scan the header for fields which are usually contained in mailing list software. This method is automatically called when a list group is constructed **from()** an existing header or message. Returned are the names of the list header fields found, in scalar context the amount. An empty list/zero indicates that this is not a mailing list message. Please warn the author of MailBox if you see that to few or too many fields are included. Improves base, see "Internals" in Mail::Message::Head::FieldGroup - $obj-\>**detected**($type, $software, $version) Inherited, see "Internals" in Mail::Message::Head::FieldGroup ### Error handling Extends "Error handling" in Mail::Message::Head::FieldGroup. - $obj-\>**AUTOLOAD**() Inherited, see "Error handling" in Mail::Reporter - $obj-\>**details**() Produce information about the detected/create list group, which may be helpful during debugging, by default to the selected file handle. Improves base, see "Error handling" in Mail::Message::Head::FieldGroup - $obj-\>**notImplemented**() Inherited, see "Error handling" in Mail::Reporter - $obj-\>**print**( \[$fh\] ) Inherited, see "Error handling" in Mail::Message::Head::FieldGroup ### Cleanup Extends "Cleanup" in Mail::Message::Head::FieldGroup. - $obj-\>**DESTROY**() Inherited, see "Cleanup" in Mail::Reporter ## DETAILS ### Mailing list fields *Detected lists* The Mail::Message::Head::ListGroup class can detect many different mailing lists, some of which are very popular and some of which are rare. Numerous fields in a header are added when the message is passed through a mailing list server. Each list software has defined its own fields, sometimes woth conflicting definitions. There are also two RFCs about mailing list: `"rfc2919"` and `"rfc2369"`. The following lists are currently detected. Between parenthesis is the string returned by **type()** when that differs from the software name. - • CommuniGate Legacy commercial MacOS implementation by Stalker Software Inc. \ - • CommuniGate Pro (CommuniGatePro) Commercial rfc2919 compliant implementation by Stalker Software Inc. \ - • Ecartis Commercial mailing list manager, formerly known as Listar. Produced by NodeRunner Computing. See \. - • Ezmlm Open Source mailing list manager, available from \. - • FML Open Source mailing list manager, see \. - • Listar Old name for Ecartis. - • Listbox Mailing lists defined at \. - • Mailman GNU's mailing list manager, available from \. - • Majordomo Free (licenced) mailing list manager by Great Circle Associates, available from \ - • Smartlist Related to procmail, as expressed by their shared main page at \. - • Yahoo! Groups (YahooGroups) Mailing lists defined at \. - • Listserv Commercial mailing list manager, produced by L-Soft. See \. ## DIAGNOSTICS - Error: cannot convert "$string" into an address object. The new(address) is coerced into a Mail::Message::Field::Address, which fails. Have a look at **Mail::Message::Field::Address::coerce()** to see what valid arguments are. Cast by `new()` - Error: class $package does not implement method $method. Fatal error: the specific `$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. Cast by `notImplemented()` ## SEE ALSO This module is part of Mail-Message version 4.05, built on April 10, 2026. Website: *http://perl.overmeer.net/mailbox/* ## LICENSE For contributors see file ChangeLog. This software is copyright (c) 2001-2026 by Mark Overmeer. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.