WeberTrivia.com -> PHP Manual -> session

Description

bool session_register ( mixed name [, mixed ...])

session_register() accepts a variable number of arguments, any of which can be either a string holding the name of a variable or an array consisting of variable names or other arrays. For each name, session_register() registers the global variable with that name in the current session.

Caution

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.

register_globals: important note: Since PHP 4.2.0, the default value for the PHP directive register_globals is off. The PHP community encourages all to not rely on this directive but instead use other means, such as the superglobals.

Caution

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.

Caution

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

This function returns TRUE when all of the variables are successfully registered with the session.

If session_start() was not called before this function is called, an implicit call to session_start() with no parameters will be made. $_SESSION does not mimic this behavior and requires session_start() before use.

You can also create a session variable by simply setting the appropriate member of the $_SESSION or $HTTP_SESSION_VARS (PHP < 4.1.0) array.

 <?php
// Use of session_register() is deprecated
$barney = "A big purple dinosaur.";
session_register("barney");

// Use of $_SESSION is preferred, as of PHP 4.1.0
$_SESSION["zim"] = "An invader from another planet.";

// The old way was to use $HTTP_SESSION_VARS
$HTTP_SESSION_VARS["spongebob"] = "He's got square pants.";
?>

Note: It is currently impossible to register resource variables in a session. For example, you cannot create a connection to a database and store the connection id as a session variable and expect the connection to still be valid the next time the session is restored. PHP functions that return a resource are identified by having a return type of resource in their function definition. A list of functions that return resources are available in the resource types appendix.
If $_SESSION (or $HTTP_SESSION_VARS for PHP 4.0.6 or less) is used, assign values to $_SESSION. For example: $_SESSION['var'] = 'ABC';