tmpfile.php

<?php
function getTmp() {
    // returns file handle, similar to the one returned by fopen, for the new file or false on failure.
    $handle = tmpfile();
    $path = stream_get_meta_data($handle)['uri'];
    var_dump(fwrite($handle, 'foo')); // 3
    var_dump(fread($handle, 42));     // ""
    var_dump(fgets($handle));         // false
    var_dump(file_get_contents($path)); // "foo"
    var_dump(file_exists($path));   // true

    return $path;
}

$path = getTmp();
var_dump(file_exists($path));   // false ???