unset variable in php

Question

I just read about unset variable through php manual.

The php manual says \"unset() destroys the specified variables\"

This def seems per

Answer 1

unset(self::$somethingstatic); will raise an Fatal error, because the variable is static (always there, can't be unset).

the documentation refers specifically to static variables defined inside a function, consider:

function t($stage)
{
  static $shell = 23;
  switch($stage) {
    case 1:
      $shell++;
      break;
    case 2:
      unset($shell);
      break;
    case 3:
      $shell--;
    break;
  }
  echo $shell;
}

because $shell is a static variable, it's always there (static) so any other time you mention $shell that is simply a reference - when you unset it, you are unsetting the reference (think unlink'ing a symlink) - the static variable is however still there (that's what static means).

thus if you call the above function t(1) will echo 24, t(2) will echo nothing, and t(3) will (rightly) echo 23 :)

help any?