how do I get a sidebar's id or number for use with is_active_sidebar()

From the codex

is_active_sidebar( $index ); ?> 
Parameters

$index
    (mixed) (required) Sidebar name, id or number. 

When i try any of my sidebar names it doesnt work; yet when I put in random numbers 1,2 and 3 guessing that my sidebars are numbered that way and it works, but this is not reliable. There is a trac issue about this and I suspect that there may be an issue with the function at the moment ( and also the example from twentyten in the codex seems to use a slug not a name) so what i want is a way of getting the sidebar’s name id or number as wordpress understands it.

EDIT ( this is the code i used to register the sidebar – i ended up adding the line ‘id’ => ‘right-sidebar’, after ‘name’ => etc to get the solution described below in the comment )

if ( function_exists('register_sidebar') )
register_sidebar(array(
'name' => 'Right Sidebar',
'before_widget' => '<li id="%1$s" class="widget %2$s">',
'after_widget' => '</li>',
'before_title' => '<h4>',
'after_title' => '</h4>',
));

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Found a solution to the problem. I added a line of code id => ‘my-sidebar-id’ to the register_sidebar array so now i know the sidebar ID. There may be another way of doing it but this method seems to work fine for me now anyway.

if ( function_exists('register_sidebar') )
register_sidebar(array(
'name' => 'Right Sidebar',
'id' => 'right-sidebar',
'before_widget' => '<li id="%1$s" class="widget %2$s">',
'after_widget' => '</li>',
'before_title' => '<h4>',
'after_title' => '</h4>',
));

Straight from the php docBlock:

@param mixed $index Sidebar name, id or number to check

Hard to say anything if I don’t see any code you used to register your sidebar.