title: Cross-platform development - Delphi 2011: How to made a Windows-tied library cross-platform?
body: <p>As perhaps you know already, most probably the next version of Delphi will be <a href="http://wings-of-wind.com/2009/09/11/kylix-2011/" rel="nofollow noreferrer">cross-platform</a>. Also, here are some <a href="http://wings-of-wind.com/2009/09/08/where-do-you-want-to-go-tommorow-cross-platform-native-code/" rel="nofollow noreferrer">polls</a> on the matter.</p>
  
  <p>While writing a cross-compiler isn't a thing which interests us very much now, porting a library which was/is Windows-tied to multiple platforms, certainly does. </p>
  
  <p>You can think, for example at VCL (Delphi's standard library). While it was designed for Windows only, it has value in it, and, of course, there are huge codebases which depend on it.</p>
  
  <p><strong>The question is:</strong>
  Which would be the best approach to made an application / library cross-platform aware <em>ensuring</em> a smooth conversion / upgrade path (as much as possible of course)?</p>
  
  <p>I stress it again, we are not interested which is the best way to do cross-platform development <strong>only</strong> (there were questions on this theme). We are interested also in yet another requirement: <em>The old code base / installations management.</em></p>
  
  <p>PS: Experiences and/or methodologies from similar situations with other languages (eg. C/C++) which are regarded as <em>standard practices</em> are welcomed.</p>
  
  <p>Thanks in advance.</p>