<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Oct 14, 2015, at 3:49 PM, Duncan P. N. Exon Smith <<a href="mailto:dexonsmith@apple.com" class="">dexonsmith@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">My understanding is that we don't expect clang to be used with *newer* libc++ headers, just older or equal. This kind of break is a little unfortunate, but probably fine. Ted, can you confirm?</span></div></blockquote></div><br class=""><div class="">On Apple platforms, we will always be shipping new clangs whenever the libc++ headers are updated, so I see no concerns there. That’s pretty much in line with how we handle our headers + compiler changes in general at Apple. For example, we rolled out new Objective-C changes in the last update that were widely and unconditionally adopted in our headers. Even the Clang we released the previous year can no longer parse those headers because of those language changes.</div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>