Would you please explain this a bit better?
Like some example maybe..?

so i'll try to explain now :)
my homepage uses sessions(i wrote a session handler) to store users information - some username, visited sections, etc data

i wrote a script, to check who is online right now - scanning for sessions active in last 3 minutes. script reads those session data from mysql table. data looks like this:

$session_data="user|a:2:{s:8:"username";s:6:"foobar";s:9:"useremail";s:0:"";}<some other data>..."

sou, it will be usefull to have function to get all these variables in one array. for example

$session_vars = get_session_vars($session_data);

as a result will be
$session_vars['username'] = 'foobar';
$session_vars['useremail'] = '';
...
and so on.

There is no need for a new function to do this, just change the prototype of 
session_decode function to

function session_decode($data, $overwrite_session = true);

then make the function returns an array with the session data always, this let to 
the programmer to choose overwrite the $_SESSION or just get the decoded array.

I think there is dup of this request.

Use php_serialize serialize handler, then you'll not have such issue.

php_serialize is available 5.6 or later.

php_serialize will be available from PHP 5.5.4.

http://git.php.net/?p=php-
src.git;a=commit;h=c51f77fe83cea3a48d89423863e6916b77628e47