[swift-users] Why we need `__attribute__((sentinel(0,1)))`?

[哀殿]

Hello Swift community,
 
I found  `__attribute__((sentinel(0,1)))` at https://github.com/apple/swift-clang/blob/c52d85ede49adaec457400697b1d4c1b7ea12881/test/Analysis/variadic-method-types.m#L46.
 
But I can't imagine how different it is from the `__attribute__((sentinel))`.

So,why we need `__attribute__((sentinel(0,1)))`?
Thanks.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-users/attachments/20160907/f6d5bb2b/attachment.html>