Only variables should be passed by reference

Question

// Other variables
$MAX_FILENAME_LENGTH = 260;
$file_name = $_FILES[$upload_name][\'name\'];
//echo \"testing-\".$file_name.\"
\";
//$file_name = strtolower         


        

Answer 1

$file_extension = end(explode('.', $file_name)); //ERROR ON THIS LINE

change this line as,

$file_extension = end((explode('.', $file_name))); //no errors

Technique is simple please put one more brackets for explode,

(explode()), then only it can perform independently..