FWIW, OS X is UNIX 03 certified: <a href="http:&#x2F;&#x2F;www.opengroup.org&#x2F;openbrand&#x2F;register&#x2F;brand3612.htm" rel="nofollow">http:&#x2F;&#x2F;www.opengroup.org&#x2F;openbrand&#x2F;register&#x2F;brand3612.htm</a><p>Android, for these purposes, is, of course, Linux with a different libc, so most of the POSIXy stuff is there, even if bionic is pretty awful.