# imap_fetchheader

(PHP 4, PHP 5, PHP 7)

imap_fetchheader — Returns header for a message

### 说明

imap_fetchheader ( resource `$imap_stream` , int `$msg_number` [, int `$options` = 0 ] ) : string

This function causes a fetch of the complete, unfiltered » RFC2822 format header of the specified message.

### 参数

`imap_stream`

  由 imap_open() 返回的 IMAP 流。

`msg_number`

  The message number

`options`

  The possible `options` are:

  - `FT_UID` - The `msgno` argument is a UID
  - `FT_INTERNAL` - The return string is in "internal" format, without any attempt to canonicalize to CRLF newlines
  - `FT_PREFETCHTEXT` - The RFC822.TEXT should be pre-fetched at the same time. This avoids an extra RTT on an IMAP connection if a full message text is desired (e.g. in a "save to local file" operation)

### 返回值

Returns the header of the specified message as a text string.

### 参见

- imap_fetch_overview() - Read an overview of the information in the headers of the given message