Only Variables can be passed by reference error

Question

An error occurred in script \'/usr/local/apache2/htdocs/read.php\' on line 197: Only variables should be passed by reference (line 196 is $ext = strtolo

Answer 1

You need to make the result of explode() a variable before you pass it on

$var = explode('.',$filename);
$ext = strtolower(array_pop($var));