Xcode: symbol(s) not found for architecture armv7

Question

I have this message from Xcode

Ld /Users/myUsername/Library/Developer/Xcode/DerivedData/myApp-gqsubryokdmrjmczxeqypzcgpths/Build/Intermediates/myApp.build/Debug-iphoneos/myApp.build/Objects-normal/armv7/myApp normal armv7
    cd /Users/myUsername/Documents/_IPAD/myApp
    setenv IPHONEOS_DEPLOYMENT_TARGET 4.3
    setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"


/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk -L/Users/myUsername/Library/Developer/Xcode/DerivedData/myApp-gqsubryokdmrjmczxeqypzcgpths/Build/Products/Debug-iphoneos -F/Users/myUsername/Library/Developer/Xcode/DerivedData/myApp-gqsubryokdmrjmczxeqypzcgpths/Build/Products/Debug-iphoneos -filelist /Users/myUsername/Library/Developer/Xcode/DerivedData/myApp-gqsubryokdmrjmczxeqypzcgpths/Build/Intermediates/myApp.build/Debug-iphoneos/myApp.build/Objects-normal/armv7/myApp.LinkFileList -dead_strip -fobjc-arc -fobjc-link-runtime -miphoneos-version-min=4.3 -framework AudioToolbox -framework SystemConfiguration -framework QuartzCore -framework OpenAL -framework CoreGraphics -framework CFNetwork -framework MessageUI -framework CoreData -framework AVFoundation -framework StoreKit -framework UIKit -framework Foundation -o /Users/myUsername/Library/Developer/Xcode/DerivedData/myApp-gqsubryokdmrjmczxeqypzcgpths/Build/Intermediates/myApp.build/Debug-iphoneos/myApp.build/Objects-normal/armv7/myApp



Undefined symbols for architecture armv7:
  "_OBJC_CLASS_$_ViewController", referenced from:
      objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)

What exactly is not found? If it is saying that something was not found where is this not found stuff being looked for? Or in other words, if xcode is searching for something it is searching somewhere, where and what?

Answer 1

I just ran into this. Turns out I didn't add the new source to all of the targets that needed it. Maybe this will help someone in the future.. :)

Answer 2

I got same error after updating xCode 6beta to xCode 6.0.1. After spending a lot of time I fixed it by deleting "Derived Data" from Window -> Organizer -> Projects -> #Select project# and pressed Delete in the "Derived Data".

Answer 3

The ViewController object is not found and it was referenced within AppDelegate. You do not link ViewController into your app. Check if your Compile Sources section within the Build Phases of your project shows ViewController.m.