can test the if relationship is significant in cancor?

i have try hard to find the answer by google,but i can not find any solution.
so i wan to ask:
1,can we test the if canonical relationship is significant after using cancor?
2,if it can,how? 
3,if not,is it under-developed or there is not need to do it?or there is no good way to do it?

i hope my question is not too silly.