isset() or session_is_registred()

[danzene]

what are the advantages or dis, of using the session_is_registered() function in my conditional statement, instead of using the isse() function? which one should i be using? for checking session vars?

session_start();
session_register("open_files");
if (! isset($open_files)){
$open_files = array ();
}
if (! isset($open_files[$ID])){
$open_files[$ID]=file("$text_dir/$ID");
}

[[deleted]]

The session_is_registered function is meant to see if a variable exists in a session. This says nothing about wether that variable is still available in the script.
Try this:

session_start();
$r='hello';
session_register('r');
unset($r);
if (session_is_registered('r'))
{
echo 'r is regisered';
}
else
{
echo 'r is not regisered';
}
if (isset($r))
{
echo 'r exists';
}
else
{
echo 'r does not exists';
};