Limited friend list in Open Graph

I received a question from one of the users of my application, and I am doubting if this is a programming bug on our end. When requesting the friend list of the user, the API only returned 480 out of 580 friends. Is the friend list limited to this number? Or is it likely that the other 100 users have very strict pri开发者_开发百科vacy settings regarding external applications? If none of these two questions is true there must be a bug in my coding, but before I dive in I thought I'd ask.

Use ?limit=5000 or a higher amount because the default limit is 500. Otherwise, make multiple calls using the next and prev navigation links included in the json response. The reason you are getting 480 instead of 500 is probably because users have changed their privacy settings or opted out of Facebook application platform entirely. Their query first gets 500 friends, and then removes the people that have opted out.