title: Portable Class Library vs. library project
body: <p>I want to know the difference between PCL (Portable Class Library) and a normal library. </p>
  
  <p>PCL uses profiles with which it can be determined which platforms and features are available. Both can generate a DLL which can be used on different platforms. For a normal library project you can also set the target framework (e.g. .NET 3.5). <a href="http://developer.xamarin.com/guides/cross-platform/application_fundamentals/building_cross_platform_applications/sharing_code_options/" rel="noreferrer">Xamarin</a> says that <code>#if</code> compiler directives are only suitable for Shared Projects, which means they are not used in PCL. I think the PCL and the library project are very similar.</p>
  
  <p>So what are the differences, when dealing with different mobile platforms?</p>