I've got an HTML form that has a PHP pgm to write the results to a file. I've basically copied it from The Web. It's not rocket surgery. It's running with PHP 7 on a Raspberry Pi with the most recent Raspbian. The PHP pgm reports that the file is writeable, that it succeeded, and so on, but the file remains empty. I've changed the permissions to 777 (for testing) and that doesn't help. I'm stumped. Here is the HTML: …