(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::close — Closes a previously opened database connection
$connection
   , int $close_type
   )Closes a previously opened database connection.
Note:
Failing to call the parent implementation may cause memory leaks or crash PHP. This is not considered a bug. Please, keep in mind that the mysqlnd library functions have never been designed to be exposed to the user space.
connectionThe connection to be closed. Do not modify!
close_type
      Why the connection is to be closed. The value
      of close_type is one of
      MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT,
      MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT,
      MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED or
       MYSQLND_UH_MYSQLND_CLOSE_LAST. The
       latter should never be seen, unless the default
       behaviour of the mysqlnd library
       has been changed by a plugin.
     
   Returns TRUE on success.
   Otherwise, returns FALSE
  
Example #1 MysqlndUhConnection::close() example
<?php
function close_type_to_string($close_type) {
 $mapping = array(
  MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED => "MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED",
  MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT => "MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT",
  MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT => "MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT",
  MYSQLND_UH_MYSQLND_CLOSE_LAST => "MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT"
 );
 return (isset($mapping[$close_type])) ? $mapping[$close_type] : 'unknown';
}
class proxy extends MysqlndUhConnection {
  public function close($res, $close_type) {
   printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
   printf("close_type = %s\n", close_type_to_string($close_type));
   /* WARNING: you must call the parent */
   $ret = parent::close($res, $close_type);
   printf("%s returns %s\n", __METHOD__, var_export($ret, true));
   return $ret;
 }
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->close();
?>
The above example will output:
proxy::close(array ( 0 => NULL, 1 => 0, )) close_type = MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT proxy::close returns true