How to get an array of sentences using CFStringTokenizer?

I've created an string tokenizer like this:

stringTokenizer = CFStringTokenizerCreate(
                         NULL
                         , (CFStringRef)str
                         , CFRangeMake(0, [str length])
                         , kCFStringTokenizerUnitSentence
                         , userLocale);

But how do I obtain those sentences now from the tokenizer? The CF String Programming Guide doesn't mention CFStringTokenizer or tokens (did a full-text search in the PDF).