title: Multiple Interface declarations in one file
body: <p>I am really struggling with with passing variables from one class to another.  I was following the answer in <a href="https://stackoverflow.com/questions/5210535/passing-data-between-view-controllers">this</a> question, and was able to implement the first part (Passing Data Forward) successfully.  My problem is when I get to the second part (Passing Data Back), I get hung up on <code>4)</code> where I need to declare an interface for my second.h file.  I already have an interface declared in that .h file:</p>
  
  <pre><code>@interface RootViewController : UITableViewController &lt;UISplitViewControllerDelegate&gt;{
  </code></pre>
  
  <p>And when I try to declare another one, I run into lots of errors.  I read that it is possible, I am just not sure the exact syntax I guess.</p>
  
  <p>Here's the complete .h file</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  
  @protocol SubstitutableDetailViewController
  - (void)showRootPopoverButtonItem:(UIBarButtonItem *)barButtonItem;
  - (void)invalidateRootPopoverButtonItem:(UIBarButtonItem *)barButtonItem;
  @end
  
  
  @interface RootViewController : UITableViewController &lt;UISplitViewControllerDelegate&gt;{
  
      UISplitViewController *splitViewController;
  
      UIPopoverController *popoverController;    
      UIBarButtonItem *rootPopoverButtonItem;
  
      NSMutableArray *logMessages;
  }
  
  @property (nonatomic, assign) IBOutlet UISplitViewController *splitViewController;
  
  @property (nonatomic, retain) UIPopoverController *popoverController;
  @property (nonatomic, retain) UIBarButtonItem *rootPopoverButtonItem;
  
  
  @end
  </code></pre>