---------------------
is_session() FUNCTION
---------------------

  ------------
  USAGE FORMAT
  ------------

    Where $rv is the numeric return value of the function:
    
    $rv = &is_session();

  -----------
  DESCRIPTION
  -----------

    Returns whether or not a cookie-based PTM Session is currently in progress
    based on the existence of $_SESSION{'ID'}. If the hash value is defined a
    current session is assumed. If the hash value is not defined no session is
    thought to exist.

  ---------
  ARGUMENTS
  ---------

    NONE

  -------
  RETURNS
  -------

    1 if a session is currently in progress.
    0 if no session is in progress.

  --------------
  USAGE EXAMPLES
  --------------

    -----------------------------------------------
    Example 1: If a Session Exists, End the Session
    -----------------------------------------------

      <?:
        if (&is_session()) {
          &end_session();
        }
      ?>

  --------
  SEE ALSO
  --------

    TAGS

      PREPROCESS

    VARIABLES

      %_COOKIES, %_SESSION, %_SET_COOKIES

    FUNCTIONS

      delete_cookie(), end_session(), session_add(), session_delete(),
      session_domain(), session_id(), session_name(), session_path(),
      session_secure(), set_cookie(), start_session(), update_session()