[jQuery] Why (function($){ ...})(jQuery) instead of (function(){var $ = jQuery; ...})()?

[jfine]

The (rather long) subject line says it all.

This idiom is widely used to avoid having to assume $ == jQuery and at
the same time avoiding writing jQuery all the time.
   (function($){
        ...
    })(jQuery)

I'm wondering if instead this would work.
  (function(){
      var $ = jQuery;
           ...
     })()

The reason I ask is that I'd like to shorthand several things in this
way.  The first method requires me to go down to the end of a (long)
function body to find out what, say '_' and 'C' really mean (private
and Constants, say), whereas the second method tells me up front.

I know enough JavaScript to think of this alternative approach, but
not enough to be sure that it will work in all relevant circumstances.

--
Jonathan