imap_uid

(PHP 4, PHP 5, PHP 7, PHP 8)

imap_uidThis function returns the UID for the given message sequence number

Description

imap_uid(IMAP\Connection $imap, int $message_num): int|false

This function returns the UID for the given message sequence number. An UID is a unique identifier that will not change over time while a message sequence number may change whenever the content of the mailbox changes.

This function is the inverse of imap_msgno().

Parameters

imap

An IMAP\Connection instance.

message_num

The message number.

Return Values

The UID of the given message.

Changelog

Version Description
8.1.0 The imap parameter expects an IMAP\Connection instance now; previously, a valid imap resource was expected.

Notes

Note:

This function is not supported by POP3 mailboxes.

See Also

  • imap_msgno() - Gets the message sequence number for the given UID

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User Contributed Notes 4 notes

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8
Denis Rendler
9 years ago
I would like to point out that, at least in the case of Gmail, the UIDs of emails are changed if they are moved from one folder to another. Even if moved back to the same folder the UIDs get incremented and thus changed.
I found this the hard way after relaying on the notion that UIDs do not change as I found almost everywhere in the docs.
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5
steve_foley at excite dot com
22 years ago
Please note that message_id in the header is NOT the UID - and its dangerous to use as many mail progs don't put a message id in
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4
Maikel
14 years ago
Be aware that the uid is unique in a single mailbox. That means a message can have as much uids as mailboxes
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2
Andreas Seeger
16 years ago
The uid will change in case of unsing imap_expunge. Be shure that
all work ist done before using imap_expunge.
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