# imap_uid

(PHP 4, PHP 5, PHP 7)

imap_uid — This function returns the UID for the given message sequence number

### 说明

imap_uid ( resource `$imap_stream` , int `$msg_number` ) : int

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().

### 参数

`imap_stream`

  由 imap_open() 返回的 IMAP 流。

`msg_number`

  The message number.

### 返回值

The UID of the given message.

### 注释

> Note:

> This function is not supported by POP3 mailboxes.

### 参见

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