How to fix the session_register() deprecated issue?

Use $_SESSION directly to set variables. Like this:

$_SESSION['name'] = 'stack';

Instead of:

$name = 'stack';
session_register("name");

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Don't use it. The description says:

Register one or more global variables with the current session.

Two things that came to my mind:

1. Using global variables is not good anyway, find a way to avoid them.
2. You can still set variables with $_SESSION['var'] = "value".

See also the warnings from the manual:

If you want your script to work regardless of register_globals, you need to instead use the $_SESSION array as $_SESSION entries are automatically registered. If your script uses session_register(), it will not work in environments where the PHP directive register_globals is disabled.

This is pretty important, because the register_globals directive is set to False by default!

Further:

This registers a global variable. If you want to register a session variable from within a function, you need to make sure to make it global using the global keyword or the $GLOBALS[] array, or use the special session arrays as noted below.

and

If you are using $_SESSION (or $HTTP_SESSION_VARS), do not use session_register(), session_is_registered(), and session_unregister().