tempnam won't write to tmp directory

[SchweppesAle]

Trying to write my code's output to a csv file.  However, the following doesn't seem to be working

 

$tmpfname = tempnam("/tmp/", "FOO");
  
  $fp = fopen($tmpfname, 'w');
  $write_file = fwrite($fp, $output);
  fclose($fp);
  echo var_dump($write_file).'<br>';
  echo var_dump($tmpfname).'<br>';
  echo '<a href = "'.$tmpfname.'">download</a>';

 

output:

int(7)

string(14) "/tmp/FOOGfqKpL"

download//it's a link, ii just pasted this in here

 

the link takes you to ourdomain.com/tmp/FOOGfqKpL

 

also, the tmp folder's directory permissions are set to 777