MySQL ストアド プロシージャを使用するときに PHP で OUT パラメータにアクセスする方法

<code class="php">$mysqli = new mysqli(  "HOST", "USR", "PWD", "DBNAME" );
$ivalue=1;

// Execute the stored procedure and store the result.
$res = $mysqli->multi_query( "CALL myproc($ivalue,@x);SELECT @x" );

if( $res ) {
    $results = 0;

    // Iterate through the results.
    do {
        if ($result = $mysqli->store_result()) {

            // Display the result header.
            printf( "<b>Result #%u</b>:<br/>", ++$results );

            // Fetch and display the OUT parameter value.
            while( $row = $result->fetch_row() ) {
                foreach( $row as $cell ) {
                    echo $cell, "&amp;nbsp;";
                }
            }

            $result->close();
            if( $mysqli->more_results() ) echo "<br/>";
        }
    } while( $mysqli->next_result() );
}

// Close the mysqli connection.
$mysqli->close();</code>