title: Xcode and Objective-C++ can't find <cstdio>
body: <p>I'm writing Cocoa code that uses some classes defined in a C++ library.  I give the filename the extension .mm, and things are usually fine.</p>
  
  <p>But not always.  Sometimes Xcode 4 disappoints me with: "Lexical or Preprocessor issue:  'cstdio' not found".   I can't figure out how to make Xcode find it.  Nor can I figure out why it works sometimes, but not others.  What do you think?</p>
  
  <p>Edit:  Noise.   My filename extension was not .mm, but rather .m.   :(   There is not, and there never was, a problem.  See below.</p>