$form_state for an autocomplete callback I'm trying to get the value of $form_state for my autocomplete textfield.

Basically, I have a search textfield and checkboxes to restrict the autocomplete.  What would be the best way of passing the checkbox values to the autocomplete?
The autocomplete callback just gets the string that needs to be auto-completed.
In your case, the only solution I can think of is that the checkboxes use an AJAX callback that is used to set a value the autocomplete function can then access.