(PHP 4, PHP 5, PHP 7, PHP 8)
imap_mime_header_decode — Decode MIME header elements
$string): array|falseDecodes MIME message header extensions that are non ASCII text (see » RFC2047).
stringThe MIME text
   The decoded elements are returned in an array of objects, where each
   object has two properties, charset and 
   text.
  
   If the element hasn't been encoded, and in other words is in
   plain US-ASCII, the charset property of that element is
   set to default.
  
   The function returns false on failure.
  
Example #1 imap_mime_header_decode() example
<?php
$text = "=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@example.com>";
$elements = imap_mime_header_decode($text);
for ($i=0; $i<count($elements); $i++) {
    echo "Charset: {$elements[$i]->charset}\n";
    echo "Text: {$elements[$i]->text}\n\n";
}
?>
The above example will output:
Charset: ISO-8859-1 Text: Keld Jørn Simonsen Charset: default Text: <keld@example.com>
In the above example we would have two elements, whereas the first element had previously been encoded with ISO-8859-1, and the second element would be plain US-ASCII.