Facebook应用程序（非用户）访问令牌到期

Facebook APP访问令牌会过期吗？这些令牌与USER令牌不同；他们是这样获得的：

Do Facebook APP access tokens expire? These tokens are different than the USER tokens; they are acquired like this:

https://graph.facebook.com/oauth/access_token?grant_type=client_credentials&client_id={0}&client_secret={1})

如文档的应用程序登录部分所述在 http://developers.facebook.com/docs/authentication/ 。

as described in the App Login section of the document at http://developers.facebook.com/docs/authentication/.

在任何情况下它们都将失效吗？

Are there any circumstances under which they will become invalid?

注意：这不是关于USER访问令牌（明确记录）的问题。有一个相同的问题 http://facebook.*.com/questions/7322063 / does-app-login-access-token-expire 错误地关闭，因为它与有关用户访问令牌的另一个问题重复。

NB: This is NOT a question about USER access tokens (which are clearly documented). There was an identical question http://facebook.*.com/questions/7322063/does-app-login-access-token-expire wrongly closed as duplicate of another question about USER access tokens.