Description of Problem: flock($open_fp, LOCK_EX) always returns a false value
(and fails to lock).

Version-Release number of selected component (if applicable): php-4.0.6-13

How Reproducible: I used the following command-line script (but the bug occurs
from within mod_php too):

#!/usr/bin/php -q
<?php
  if (!($fp = fopen('/tmp/lock.file', 'r'))) {
    die("couldn't open file to lock\n");
  } else {
    flock($fp, LOCK_EX) or print "couldn't get lock!!\n";
    print "HELLO\n"; sleep(5); print "GOODBYE\n";
    flock($fp, LOCK_UN);
    fclose($fp);
  }
?>

Additional Information:
It was working fine in php-4.0.6-9.7.0