The PHP tmpfile() function creates a temporary file with a unique name in read-write (w+) mode.

The file is automatically removed when closed, with fclose() or when the script ends.

<?php
$temp = tmpfile();

fwrite($temp, 'Testing');

// rewind to the beginning of the file
rewind($temp);

// read 1k from file
echo fread($temp, 1024);

fclose($temp);
?>

// creates a temporary file with a unique name in read-write (w+) mode
// writes to the file
// reads from the file
// closes the file

tmpfile()