POSIXgetaddrinfo分配稍后必须使用freeaddrinfo释放的内存。参见http://manpages.ubuntu.com/manpages/xenial/en/man3/getaddrinfo.3.html为了简化API,我创建了这个函数:importFoundationenumSystemError:Swift.Error{casegetaddrinfo(Int32,Int32?)}publicfuncgetaddrinfo(node:String?,service:String?,hints:addrinfo?)throws->[addrinfo]{varerr