symbol(s) not found for architecture i386

Question

When trying to compile with Xcode, I am getting the following error:

  **Ld /Users/doronkatz/Library/Developer/Xcode/DerivedData/iKosher-bphnihrngmqtkqfgievrrumzmyce/Build/Products/Debug-iphonesimulator/iKosher.app/iKosher normal i386
    cd /Users/doronkatz/Sites/xCode/iKosher
    setenv MACOSX_DEPLOYMENT_TARGET 10.6
    setenv PATH "/Xcode4/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Xcode4/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Xcode4/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 -arch i386 -isysroot /Xcode4/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator4.2.sdk -L/Users/doronkatz/Library/Developer/Xcode/DerivedData/iKosher-bphnihrngmqtkqfgievrrumzmyce/Build/Products/Debug-iphonesimulator -L/Users/doronkatz/Sites/xCode/iKosher -F/Users/doronkatz/Library/Developer/Xcode/DerivedData/iKosher-bphnihrngmqtkqfgievrrumzmyce/Build/Products/Debug-iphonesimulator -filelist /Users/doronkatz/Library/Developer/Xcode/DerivedData/iKosher-bphnihrngmqtkqfgievrrumzmyce/Build/Intermediates/iKosher.build/Debug-iphonesimulator/iKosher.build/Objects-normal/i386/iKosher.LinkFileList -mmacosx-version-min=10.6 -all_load -ObjC -Xlinker -objc_abi_version -Xlinker 2 -lz -framework Security -framework CFNetwork -framework CoreData -framework Foundation -framework UIKit -framework CoreGraphics -framework QuartzCore -o /Users/doronkatz/Library/Developer/Xcode/DerivedData/iKosher-bphnihrngmqtkqfgievrrumzmyce/Build/Products/Debug-iphonesimulator/iKosher.app/iKosher

Undefined symbols for architecture i386:
  "_UTTypeCreatePreferredIdentifierForTag", referenced from:
      +[ASIHTTPRequest mimeTypeForFileAtPath:] in ASIHTTPRequest.o
  "_UTTypeCopyPreferredTagWithClass", referenced from:
      +[ASIHTTPRequest mimeTypeForFileAtPath:] in ASIHTTPRequest.o
  "_kUTTagClassMIMEType", referenced from:
      +[ASIHTTPRequest mimeTypeForFileAtPath:] in ASIHTTPRequest.o
  "_kUTTagClassFilenameExtension", referenced from:
      +[ASIHTTPRequest mimeTypeForFileAtPath:] in ASIHTTPRequest.o
  "_SCNetworkReachabilitySetCallback", referenced from:
      -[Reachability startNotifier] in Reachability.o
  "_SCNetworkReachabilityScheduleWithRunLoop", referenced from:
      -[Reachability startNotifier] in Reachability.o
  "_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from:
      -[Reachability stopNotifier] in Reachability.o
  "_SCNetworkReachabilityCreateWithName", referenced from:
      +[Reachability reachabilityWithHostName:] in Reachability.o
  "_SCNetworkReachabilityCreateWithAddress", referenced from:
      +[Reachability reachabilityWithAddress:] in Reachability.o
  "_SCNetworkReachabilityGetFlags", referenced from:
      -[Reachability currentReachabilityStatus] in Reachability.o
      -[Reachability isReachable] in Reachability.o
      -[Reachability isConnectionRequired] in Reachability.o
      -[Reachability isConnectionOnDemand] in Reachability.o
      -[Reachability isInterventionRequired] in Reachability.o
      -[Reachability isReachableViaWWAN] in Reachability.o
      -[Reachability isReachableViaWiFi] in Reachability.o
      ...
ld: symbol(s) not found for architecture i386
collect2: ld returned 1 exit status**

Not sure what it means.

Answer 1

If you get this sort of thing appearing suddenly, it usually means the project is missing some frameworks it needs. Libraries and dependent projects can require frameworks, so if you've added one recently then that can cause this error.

To add frameworks, right click on the project name in the project view, select Add, then select Existing frameworks... from the list. Then find the framework with the symbols you're missing.

As to how you find which frameworks you need, I've found using google the easiest, though you could probably use the Xcode help search too. Search for one of the symbols, doing your best to work out the unmangled name (e.g., SCNetworkReachabilityGetFlags), and then the first documentation link you find at developer.apple.com is often the right one. You usually don't have to hunt very far. In this case, that's this page:

https://developer.apple.com/documentation/systemconfiguration/scnetworkreachability-g7d

Then at the top of the page, it tells you which framework to use, SystemConfiguration in this case. So add that to the project, and compile again.

Then just keep doing this until it works...

Edit: I've never used the simulator, but this is what you do on the device - I assume it's the same...

Answer 2

I've been stumped by this one before only to realize I added a data-only @interface and forgot to add the empty @implementation block.

Answer 3

I fixed a similar error on my project by changing the Build Settings > Architectures for ALL of my targets.

The problem: When I upgraded from Xcode 4.4 to Xcode 4.5, my project still compiled fine on the simulator but did not compile on devices. On devices it threw the error "symbol(s) not found for architecture armv7s," along with the misleading "Apple Mach-O Linker Error" and "clang: error: linker command failed with exit code 1 (use -v to see invocation)."

The cause (in my case): My project had multiple targets, and even though the Build Settings > Architectures for the main target was set to include armv7s architecture, the main target depended on another target (listed under Build Phases > Dependencies), and I hadn't thought to reset the Build Settings > Architectures for that other target, and I had to change that to include armv7s. I suppose the simulator and device run on different architectures, and that's why the simulator was OK while the device wasn't.

Answer 4

The problem is that target membership for the added filed is missing to the app target .So select the file and add the checkmark to the box of target membership

For example if the error shown in a method definition in common.m

Answer 5

This happened to me while trying to copy over the PSPDFKIT demo library into my project. I followed all the instructions in the site + all the suggestions on this page.. for some reason it kept on giving the above error, the problem was that if i grepped the message in the error method.. it only appeared in the binary (obviously I have no access to the source code b/c I have to pay for it).

I noticed this in the instruction page though:

So I went to the guts of that config file and found this:

OTHER_LDFLAGS=$(inherited) -ObjC -fobjc-arc -lz -framework CoreText -framework CoreMedia -framework MediaPlayer -framework AVFoundation -framework ImageIO -framework MediaPlayer -framework MessageUI -framework CoreGraphics -framework Foundation -framework QuartzCore -framework AVFoundation -framework CFNetwork -framework MobileCoreServices -framework SystemConfiguration -weak_framework UIKit

Then I went to the sample project provided by the author of the said library.. and noticed that the previous flags where copied verbatim to the other linker flags in my build settings.. however in my project.. they were not!.. So i simply copied and pasted them into my project's build settings other linker flags and everything worked!

take away point: if you are relying on some .xcconfig file on your setup, double check with a sample code source or something and make sure that it has actually been applied.. it wasn't applied properly in my case

Answer 6

I solved it using the following method (for XCode 4):

1) Select the project in the project navigation window which will show project summary on right

2) Select 4th tab build phases

3) Select Link binary with library option

4) Add framework for which you are getting

5) Move the framework from main folder to the frameworks folder

6) Build it again and errors are gone.