<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></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 2, 2016, at 6:24 PM, Jean-Denis Muys via swift-users <<a href="mailto:swift-users@swift.org" class="">swift-users@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Hi,<div class=""><br class=""></div><div class="">Xcode seems to think that [some] builtins can be used from Swift. It autocompletes popcount for example, and command-clicking the function opens a bona fide interface file, with the following declaration (among others):<br class=""><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: menlo;" class=""><span style="font-variant-ligatures:no-common-ligatures;color:rgb(187,44,162)" class="">public</span><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(187,44,162)" class="">func</span><span style="font-variant-ligatures:no-common-ligatures" class=""> __builtin_popcount(</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(187,44,162)" class="">_</span><span style="font-variant-ligatures:no-common-ligatures" class="">: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(112,61,170)" class="">UInt32</span><span style="font-variant-ligatures:no-common-ligatures" class="">) -> </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(112,61,170)" class="">Int32</span></div></div><div class=""><span style="font-variant-ligatures:no-common-ligatures;color:rgb(112,61,170)" class=""><br class=""></span></div><div class="">However, when I try to compile code that uses that function, I get an unresolved identifier compiler error.</div><div class=""><br class=""></div><div class="">I guess I need to import some module, but which one?</div></div></div></div></blockquote><br class=""></div><div>Huh, that is odd. It should not be made available to Swift code like that. Please file a jira or radar ticket, thank you!</div><div><br class=""></div><div>-Chris</div><br class=""></body></html>