title: linker errors when integrating admob sdk into iOS app
body: <p>I integrated Google's AdMob SDK into a working iPhone app.  I'm getting 12 errors that all start with 'Apple Mach-O Linker (Id) Error'.  The text of the error messages typically refer to a low level objective C object called from a google library.  For example:</p>
  
  <p><em>Undefined symbols for architecture i386:
    "_NSInMemoryStoreType", referenced from:
        anon in libGoogleAnalytics.a(GAIDataStore.o)
        +[GAIDataStore memoryContextWithModel:withError:] in libGoogleAnalytics_debug.a(GAIDataStore.o)</em></p>
  
  <p>I thought I might not be linking a necessary framework but that all seems to be in order.  I followed the instructions at <a href="https://developers.google.com/mobile-ads-sdk/docs/" rel="noreferrer">https://developers.google.com/mobile-ads-sdk/docs/</a> and my linked libraries tab looks like this:</p>
  
  <p><img src="https://i.stack.imgur.com/5R9pJ.png" alt="screenshot of linked libraries"></p>
  
  <p>Unless I'm mistaken, it includes the frameworks that AdMob needs.  Any suggestions much appreciated.</p>