(PHP 5, PHP 7)
iconv_mime_decode_headers — Decodes multiple MIME header fields at once
$encoded_headers
   [, int $mode = 0
   [, string $charset = ini_get("iconv.internal_encoding")
  ]] )Decodes multiple MIME header fields at once.
encoded_headersThe encoded headers, as a string.
mode
       mode determines the behaviour in the event
       iconv_mime_decode_headers() encounters a malformed
       MIME header field. You can specify any combination
       of the following bitmasks.
       
| Value | Constant | Description | 
|---|---|---|
| 1 | ICONV_MIME_DECODE_STRICT | If set, the given header is decoded in full conformance with the standards defined in » RFC2047. This option is disabled by default because there are a lot of broken mail user agents that don't follow the specification and don't produce correct MIME headers. | 
| 2 | ICONV_MIME_DECODE_CONTINUE_ON_ERROR | If set, iconv_mime_decode_headers() attempts to ignore any grammatical errors and continue to process a given header. | 
charset
       The optional charset parameter specifies the
       character set to represent the result by. If omitted,
       iconv.internal_encoding
       will be used.
      
   Returns an associative array that holds a whole set of
   MIME header fields specified by
   encoded_headers on success, or FALSE
   if an error occurs during the decoding.
  
Each key of the return value represents an individual field name and the corresponding element represents a field value. If more than one field of the same name are present, iconv_mime_decode_headers() automatically incorporates them into a numerically indexed array in the order of occurrence.
Example #1 iconv_mime_decode_headers() example
<?php
$headers_string = <<<EOF
Subject: =?UTF-8?B?UHLDvGZ1bmcgUHLDvGZ1bmc=?=
To: example@example.com
Date: Thu, 1 Jan 1970 00:00:00 +0000
Message-Id: <example@example.com>
Received: from localhost (localhost [127.0.0.1]) by localhost
    with SMTP id example for <example@example.com>;
    Thu, 1 Jan 1970 00:00:00 +0000 (UTC)
    (envelope-from example-return-0000-example=example.com@example.com)
Received: (qmail 0 invoked by uid 65534); 1 Thu 2003 00:00:00 +0000
EOF;
$headers =  iconv_mime_decode_headers($headers_string, 0, "ISO-8859-1");
print_r($headers);
?>
The above example will output:
Array
(
    [Subject] => Prüfung Prüfung
    [To] => example@example.com
    [Date] => Thu, 1 Jan 1970 00:00:00 +0000
    [Message-Id] => <example@example.com>
    [Received] => Array
        (
            [0] => from localhost (localhost [127.0.0.1]) by localhost with SMTP id example for <example@example.com>; Thu, 1 Jan 1970 00:00:00 +0000 (UTC) (envelope-from example-return-0000-example=example.com@example.com)
            [1] => (qmail 0 invoked by uid 65534); 1 Thu 2003 00:00:00 +0000
        )
)