title: Compiling Objective-C files into object files (.o)
body: <p>I have been tasked to create object .o files for an iOS project in Xcode 4. I have tried the following command which works on NSObject classes </p>
  
  <pre><code>gcc -c implemtationfile.m
  </code></pre>
  
  <p>but if I try to run the command on a class inherited from UIViewController for example I get a ton of errors starting with</p>
  
  <pre><code>UIKit/UIKit.h: No such file or directory
  </code></pre>
  
  <p>Secondly, since there are multiple files in the project, is it possible to create one .o file for all source files?</p>