imap_fetchheader

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)