isset_null.php at phc - Free PHP Code

<?php
  if(isset($a)) echo "a is set\n"; else echo "a is not set\n";
  $a = NULL;
  if(isset($a)) echo "a is set\n"; else echo "a is not set\n";
  $a = 1;
  if(isset($a)) echo "a is set\n"; else echo "a is not set\n";
  $a = NULL;
  if(isset($a)) echo "a is set\n"; else echo "a is not set\n";
?>