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Flags

property Flags: TIdMessageFlagsSet read write;

Example​

procedure MarkMessageForLocalProcessing;
var
  Msg: TIdMessage;
begin
  Msg := Email;
  if Msg = nil then Exit;

  Msg.Flags := Msg.Flags + [mfSeen, mfAnswered];
  Msg.Flags := Msg.Flags - [mfDeleted];
end;

Usage​

Flags stores IMAP mailbox state such as seen or answered separately from the message headers and body serialized by TIdMessage.

Additional Technical Info​

Flags is a set of TIdMessageFlags values representing IMAP mailbox state. Its type is TIdMessageFlagsSet. The available system flags are:

ValueIMAP spellingMeaning
mfAnswered\AnsweredThe message has been answered.
mfFlagged\FlaggedThe message is specially marked.
mfDeleted\DeletedThe message is marked for removal, not necessarily expunged.
mfDraft\DraftThe message has not completed composition.
mfSeen\SeenThe message has been read.
mfRecent\RecentThe server considers the message recent for the session.

The property is a direct value field. Reading returns a set value; assigning replaces the entire set. Use set union (+) and difference (-) when changing one flag without discarding the others, as in the example.

Mailbox metadata, not a message header​

Flags is not an RFC message header. GenerateHeader, ProcessHeaders, SaveToFile and LoadFromFile do not project it into or recover it from the saved message. Copying an .eml file therefore does not preserve this property.

Indy's IMAP retrieval paths assign the server response to both Flags and UID. IMAP store operations translate the first five values to system flags. The server-side store implementation does not accept mfRecent in its add/remove list because \Recent is server/session managed. Merely assigning this property changes only the in-memory TIdMessage; it does not issue an IMAP STORE command or update a remote mailbox.

Lifecycle and safe use​

New and cleared messages have []. ClearHeader resets Flags even though it does not reset every message setting. A later IMAP fetch can replace the complete set with the flags returned by the server.

Treat the value as a snapshot. Another client, server rule or subsequent operation can change mailbox state after it was fetched. Before destructive actions, distinguish mfDeleted from actual expunging and apply the mailbox API's concurrency and UID rules. Do not infer message content, trust or delivery status from these flags.

The example is source-reviewed only and changes only the current in-memory message; no IMAP operation was executed.

External references

Created 2026-07-15