<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=""><div class="">Hi all,</div><div class=""><br class=""></div><div class="">Inside my CFSocketCallBack a pointer to a sockaddr is provided wrapped in a CFData structure. The sockaddr could be either a sockaddr_in (IPv4) or sockaddr_in6 (IPv6) struct. In order to discover which struct you’re dealing with, the attribute sa_family can be inspected. In C this would look something like this:</div><div class=""><br class=""></div><div class=""><pre class="lang-c prettyprinted prettyprint" style="margin-top: 0px; padding: 5px; border: 0px; font-size: 13px; width: auto; max-height: 600px; overflow: auto; font-family: Consolas, Menlo, Monaco, 'Lucida Console', 'Liberation Mono', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', 'Courier New', monospace, sans-serif; background-color: rgb(239, 240, 241); color: rgb(57, 51, 24); word-wrap: normal;"><code style="margin: 0px; padding: 0px; border: 0px; font-family: Consolas, Menlo, Monaco, 'Lucida Console', 'Liberation Mono', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', 'Courier New', monospace, sans-serif; white-space: inherit;" class=""><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">struct</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> sockaddr_storage sa</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">;</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">switch</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> </span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">(((</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sockaddr</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">*)&</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sa</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">)-></span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sa_family</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">)</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">{</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">case</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> AF_INET</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">:</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
inet_ntop</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">AF_INET</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> </span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">&(((</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sockaddr_in</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">*)&</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sa</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">)-></span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sin_addr</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">),</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> </span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">...);</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">break</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">;</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">case</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> AF_INET6</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">:</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
inet_ntop</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">AF_INET6</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> </span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">&(((</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sockaddr_in6</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">*)&</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sa</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">)-></span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">sin6_addr</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">),</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);"> </span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">...);</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; color: rgb(16, 16, 148);">break</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">;</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">
</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; color: rgb(48, 51, 54);">}</span></code></pre><div class="">(from: <a href="http://stackoverflow.com/a/13167913" class="">http://stackoverflow.com/a/13167913</a>)</div></div><div class=""><br class=""></div><div class="">Wheras to do this in Swift 3, the only way I found thus far is this:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal; color: rgb(52, 149, 175);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">var</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> generic = </span><span style="font-variant-ligatures: no-common-ligatures" class="">CFDataGetBytePtr</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(data).</span><span style="font-variant-ligatures: no-common-ligatures" class="">withMemoryRebound</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(to: </span><span style="font-variant-ligatures: no-common-ligatures" class="">sockaddr</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">self</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">, capacity: 1) {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">return</span><span style="font-variant-ligatures: no-common-ligatures" class=""> $0.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">pointee</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">switch</span><span style="font-variant-ligatures: no-common-ligatures" class=""> generic.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">sa_family</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; line-height: normal; color: rgb(52, 149, 175);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">case</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">sa_family_t</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">AF_INET</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">):</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ipv4 = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">withUnsafePointer</span><span style="font-variant-ligatures: no-common-ligatures" class="">(to: &generic) {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> $0.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">withMemoryRebound</span><span style="font-variant-ligatures: no-common-ligatures" class="">(to: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">sockaddr_in</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">, capacity: 1) {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> $0.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">pointee</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""> //...</div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: rgb(4, 51, 255);" class="">case</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="color: rgb(52, 149, 175); font-variant-ligatures: no-common-ligatures;" class="">sa_family_t</span><span style="font-variant-ligatures: no-common-ligatures;" class="">(</span><span style="color: rgb(52, 149, 175); font-variant-ligatures: no-common-ligatures;" class="">AF_INET6</span><span style="font-variant-ligatures: no-common-ligatures;" class="">):</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ipv6 = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">withUnsafePointer</span><span style="font-variant-ligatures: no-common-ligatures" class="">(to: &generic) {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> $0.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">withMemoryRebound</span><span style="font-variant-ligatures: no-common-ligatures" class="">(to: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">sockaddr_in6</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">, capacity: 1) {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> $0.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">pointee</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""> //...</div><div style="margin: 0px; line-height: normal;" class=""><span style="color: rgb(4, 51, 255); font-variant-ligatures: no-common-ligatures;" class="">default</span><span style="font-variant-ligatures: no-common-ligatures;" class="">:</span></div><div style="margin: 0px; line-height: normal;" class=""> //…</div><div style="margin: 0px; line-height: normal;" class="">}</div><div style="margin: 0px; line-height: normal; color: rgb(4, 51, 255);" class=""><br class=""></div></div></div><div class="">This looks very ugly with all the closures and ``withMemoryRebound``. Is there a better way to do this? I think there should be something more “Swifty”.</div><div class=""><br class=""></div><div class="">—</div><div class="">Bouke</div></body></html>