title: Undefined symbols for architecture arm64 xcode 7.3
body: <p>I have created a static library with simple math function and built a universal binary with it. Build for active architectures only was set to NO while building this. </p>
  
  <pre><code>lipo -info libcheckC.a
  Architectures in the fat file: libcheckC.a are: armv7 x86_64 arm64 
  </code></pre>
  
  <p>I have added this file to another project and verified that
  Other linker flags have -ObjC, -lcheckC, $(inherited)</p>
  
  <p>The library is also present under "Build Phases --> Link binary with libraries".</p>
  
  <p>I have created the bridging header and added the header file to my project.</p>
  
  <p>I am still getting the error </p>
  
  <pre><code>Undefined symbols for architecture arm64:
  "_squareOf", referenced from:
        checkCLib.ViewController.calculate (__ObjC.UIButton) -&gt; () in ViewController.o
  ld: symbol(s) not found for architecture arm64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>I am using Xcode 7.3</p>
  
  <p>When I try the command manually, I fire following - copied from Xcode with added -v and going deeper from there.  I get following details.</p>
  
  <pre><code>@(#)PROGRAM:ld  PROJECT:ld64-264.3.101
  configured to support archs: armv6 armv7 armv7s arm64 i386 x86_64 x86_64h armv6m armv7k armv7m armv7em (tvOS)
  Library search paths:
  /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/
  /Users/test/Documents/MyIApps/checkCLib/checkCLib
  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphoneos
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.3.sdk/usr/lib
  Framework search paths:
  /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/
  /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Debug-iphoneos
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.3.sdk/System/Library/Frameworks/
  Undefined symbols for architecture arm64:
    "_squareOf", referenced from:
    checkCLib.ViewController.calculate (__ObjC.UIButton) -&gt; () in ViewController.o
  ld: symbol(s) not found for architecture arm64
  </code></pre>
  
  <p>The library exists at the mentioned path, contains the symbol and supports the architecture as well.</p>
  
  <pre><code>lipo -info /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/libcheckC.a
  Architectures in the fat file: /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/libcheckC.a are: armv7 x86_64 arm64 
  
  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/nm /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/libcheckC.a
  
  /Users/test/Library/Developer/Xcode/DerivedData/Build/Products/Release-universal/libcheckC.a(square.o):
  0000000000000000 T _sqaureOf
  </code></pre>