title: xcode with boost : linker(Id) Warning about visibility settings
body: <p>I have been using a boost framework from the link below for my iPhone Xcode project:
  <a href="https://goodliffe.blogspot.com/2010/09/building-boost-framework-for-ios-iphone.html" rel="noreferrer">https://goodliffe.blogspot.com/2010/09/building-boost-framework-for-ios-iphone.html</a></p>
  
  <p>it works fine but I always get hundreds of Apple Mach-O Linker(id) Warnings like:</p>
  
  <blockquote>
    <p>Direct access in __ZN5boost15program_options6detail7cmdline24handle_additional_parserERSt6vectorISsSaISsEE to global weak symbol __ZTVN5boost17bad_function_callE means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings.</p>
  </blockquote>
  
  <p>How to get rid of those warnings in code?</p>
  
  <p>edited:
  By set <strong>Symbols Hidden by Default</strong> = YES, I managed to get rid of most of the warnings but there are 3 more left which won't go away, can anyone tell me why?</p>
  
  <p>edited again:
  After a rebuild the remaining 3 warning are gone as well! So my solution did work!</p>