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XLIV. IMAP, POP3 and NNTP Functions


These functions are not limited to the IMAP protocol, despite their name. The underlying c-client library also supports NNTP, POP3 and local mailbox access methods.


This extension requires the c-client library to be installed. Grab the latest version from ftp://ftp.cac.washington.edu/imap/ and compile it.

It's important that you do not copy the IMAP source files directly into the system include directory as there may be conflicts. Instead, create a new directory inside the system include directory, such as /usr/local/imap-2000b/ (location and name depend on your setup and IMAP version), and inside this new directory create additional directories named lib/ and include/. From the c-client directory from your IMAP source tree, copy all the *.h files into include/ and all the *.c files into lib/. Additionally when you compiled IMAP, a file named c-client.a was created. Also put this in the lib/ directory but rename it as libc-client.a.

Note: To build the c-client library with SSL or/and Kerberos support read the docs supplied with the package.


To get these functions to work, you have to compile PHP with --with-imap[=DIR], where DIR is the c-client install prefix. From our example above, you would use --with-imap=/usr/local/imap-2000b. This location depends on where you created this directory according to the description above. Windows users may include the php_imap.dll DLL in php.ini

Note: Depending how the c-client was configured, you might also need to add --with-imap-ssl=/path/to/openssl/ and/or --with-kerberos=/path/to/kerberos into the PHP configure line.


The IMAP extension cannot be used in conjuction with the recode, YAZ or Cyrus extensions. This is due to the fact that they both share the same internal symbol.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

NIL (integer)

OP_DEBUG (integer)

OP_READONLY (integer)

Open mailbox read-only

OP_ANONYMOUS (integer)

Don't use or update a .newsrc for news (NNTP only)


OP_SILENT (integer)

OP_PROTOTYPE (integer)

OP_HALFOPEN (integer)

For IMAP and NNTP names, open a connection but don't open a mailbox.

OP_EXPUNGE (integer)

OP_SECURE (integer)

CL_EXPUNGE (integer)

silently expunge the mailbox before closing when calling imap_close()

FT_UID (integer)

The parameter is a UID

FT_PEEK (integer)

Do not set the \Seen flag if not already set

FT_NOT (integer)

FT_INTERNAL (integer)

The return string is in internal format, will not canonicalize to CRLF.


ST_UID (integer)

The sequence argument contains UIDs instead of sequence numbers

ST_SILENT (integer)

ST_SET (integer)

CP_UID (integer)

the sequence numbers contain UIDS

CP_MOVE (integer)

Delete the messages from the current mailbox after copying with imap_mail_copy()

SE_UID (integer)

Return UIDs instead of sequence numbers

SE_FREE (integer)


Don't prefetch searched messages

SO_FREE (integer)

SO_NOSERVER (integer)

SA_MESSAGES (integer)

SA_RECENT (integer)

SA_UNSEEN (integer)

SA_UIDNEXT (integer)


SA_ALL (integer)


This mailbox has no "children" (there are no mailboxes below this one).


This is only a container, not a mailbox - you cannot open it.

LATT_MARKED (integer)

This mailbox is marked. Only used by UW-IMAPD.


This mailbox is not marked. Only used by UW-IMAPD.

SORTDATE (integer)

Sort criteria for imap_sort(): message Date


Sort criteria for imap_sort(): arrival date

SORTFROM (integer)

Sort criteria for imap_sort(): mailbox in first From address


Sort criteria for imap_sort(): message subject

SORTTO (integer)

Sort criteria for imap_sort(): mailbox in first To address

SORTCC (integer)

Sort criteria for imap_sort(): mailbox in first cc address

SORTSIZE (integer)

Sort criteria for imap_sort(): size of message in octets

TYPETEXT (integer)




TYPEAUDIO (integer)

TYPEIMAGE (integer)

TYPEVIDEO (integer)

TYPEOTHER (integer)

ENC7BIT (integer)

ENC8BIT (integer)

ENCBINARY (integer)

ENCBASE64 (integer)


ENCOTHER (integer)

See Also

This document can't go into detail on all the topics touched by the provided functions. Further information is provided by the documentation of the c-client library source (docs/internal.txt). and the following RFC documents:

  • RFC2821: Simple Mail Transfer Protocol (SMTP).

  • RFC2822: Standard for ARPA internet text messages.

  • RFC2060: Internet Message Access Protocol (IMAP) Version 4rev1.

  • RFC1939: Post Office Protocol Version 3 (POP3).

  • RFC977: Network News Transfer Protocol (NNTP).

  • RFC2076: Common Internet Message Headers.

  • RFC2045 , RFC2046 , RFC2047 , RFC2048 & RFC2049: Multipurpose Internet Mail Extensions (MIME).

A detailed overview is also available in the books Programming Internet Email by David Wood and Managing IMAP by Dianna Mullet & Kevin Mullet.

Table of Contents
imap_8bit --  Convert an 8bit string to a quoted-printable string
imap_alerts --  This function returns all IMAP alert messages (if any) that have occurred during this page request or since the alert stack was reset
imap_append --  Append a string message to a specified mailbox
imap_base64 -- Decode BASE64 encoded text
imap_binary --  Convert an 8bit string to a base64 string
imap_body -- Read the message body
imap_bodystruct --  Read the structure of a specified body section of a specific message
imap_check -- Check current mailbox
imap_clearflag_full -- Clears flags on messages
imap_close -- Close an IMAP stream
imap_createmailbox -- Create a new mailbox
imap_delete --  Mark a message for deletion from current mailbox
imap_deletemailbox -- Delete a mailbox
imap_errors --  This function returns all of the IMAP errors (if any) that have occurred during this page request or since the error stack was reset.
imap_expunge -- Delete all messages marked for deletion
imap_fetch_overview --  Read an overview of the information in the headers of the given message
imap_fetchbody --  Fetch a particular section of the body of the message
imap_fetchheader -- Returns header for a message
imap_fetchstructure --  Read the structure of a particular message
imap_get_quota --  Retrieve the quota level settings, and usage statics per mailbox
imap_get_quotaroot --  Retrieve the quota settings per user
imap_getacl --  Gets the ACL for a given mailbox
imap_getmailboxes --  Read the list of mailboxes, returning detailed information on each one
imap_getsubscribed -- List all the subscribed mailboxes
imap_header -- Alias of imap_headerinfo()
imap_headerinfo -- Read the header of the message
imap_headers --  Returns headers for all messages in a mailbox
imap_last_error --  This function returns the last IMAP error (if any) that occurred during this page request
imap_list -- Read the list of mailboxes
imap_listmailbox -- Alias of imap_list()
imap_listscan --  Read the list of mailboxes, takes a string to search for in the text of the mailbox
imap_listsubscribed -- Alias of imap_lsub()
imap_lsub -- List all the subscribed mailboxes
imap_mail_compose --  Create a MIME message based on given envelope and body sections
imap_mail_copy -- Copy specified messages to a mailbox
imap_mail_move -- Move specified messages to a mailbox
imap_mail --  Send an email message
imap_mailboxmsginfo -- Get information about the current mailbox
imap_mime_header_decode -- Decode MIME header elements
imap_msgno --  This function returns the message sequence number for the given UID
imap_num_msg --  Gives the number of messages in the current mailbox
imap_num_recent -- Gives the number of recent messages in current mailbox
imap_open -- Open an IMAP stream to a mailbox
imap_ping -- Check if the IMAP stream is still active
imap_qprint -- Convert a quoted-printable string to an 8 bit string
imap_renamemailbox -- Rename an old mailbox to new mailbox
imap_reopen -- Reopen IMAP stream to new mailbox
imap_rfc822_parse_adrlist -- Parses an address string
imap_rfc822_parse_headers -- Parse mail headers from a string
imap_rfc822_write_address --  Returns a properly formatted email address given the mailbox, host, and personal info.
imap_scanmailbox -- Alias of imap_listscan()
imap_search --  This function returns an array of messages matching the given search criteria
imap_set_quota -- Sets a quota for a given mailbox
imap_setacl --  Sets the ACL for a giving mailbox
imap_setflag_full -- Sets flags on messages
imap_sort -- Sort an array of message headers
imap_status --  This function returns status information on a mailbox other than the current one
imap_subscribe -- Subscribe to a mailbox
imap_thread --  Return threaded by REFERENCES tree
imap_timeout --  Set or fetch imap timeout
imap_uid --  This function returns the UID for the given message sequence number
imap_undelete --  Unmark the message which is marked deleted
imap_unsubscribe -- Unsubscribe from a mailbox
imap_utf7_decode --  Decodes a modified UTF-7 encoded string.
imap_utf7_encode --  Converts ISO-8859-1 string to modified UTF-7 text.
imap_utf8 --  Converts MIME-encoded text to UTF-8






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