symbol(s) not found for architecture i386

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.

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...

Sometimes there are source files which are missing from your target.

1. examine which symbols are missing
2. target->build phases->compile source
3. add the missing source files if they are not listed
4. command+b for bliss

You can select the files that seem to be "missing" and check in the right-hand utility bar that their checkboxes are selected for the Target you are building.

You are using ASIHTTPRequest so you need to setup your project. Read the second part here

https://allseeing-i.com/ASIHTTPRequest/Setup-instructions

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.

Thought to add my solution for this, after spending a few hours on the same error :(

The guys above were correct that the first thing you should check is whether you had missed adding any frameworks, see the steps provided by Pruthvid above.

My problem, it turned out, was a compile class missing after I deleted it, and later added it back in again.

Check your "Compile Sources" as shown for the reported error classes. Add in any missing classes that you created.

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

Make sure that the missing framework is actually listed under "Target/Build Phases/Link Binary With Libraries" if not just add it. As mentioned before it usually indicates a missing framework.

In my project there were two identical framework listed, when I removed one of them I had this error, because it also removed it form the the "Link Binary With Libraries" list. I added back and the problem disappeared (and I still have two frameworks listed)

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.

Does your project depend on another project, and is that a target in that project set up to be a direct dependency of your main target? If this is the case and the dependency isn't set up, the dependent target may not be getting built for all configurations (i.e. the simulator)

Just a wild guess.

Another situation that can cause this problem is if your code calls into C++, or is called by C++ code. I had a problem with my own .c file's utility function showing up as "symbol not found" when called from Obj-C. The fix was to change the file type: in Xcode 4, use the extended info pane to set the file type to "Objective-C++ Source"; in Xcode 3, use "Get Info" to change file type to "source.cpp.objcpp".

In my case none of the posted solutions worked. I had to delete the project and make a fresh checkout from the SVN server. Lucky me the project was hosted in a version control system. Don't know what I'd do otherwise.

In a C++ project using a defined templatized class, while receiving the same error, I selected .cpp file with the defined templatized class in the Project Navigator, then Delete > Remove Reference. Also the associated .h file, while still referenced in the project, needs to have a #include statement to the .cpp as follows:

#ifndef __CircularBuffer__CircularBufferT__
#define __CircularBuffer__CircularBufferT__

... snip ...

#include "CircularBufferT.cpp"
#endif /* defined(__CircularBuffer__CircularBufferT__) */

If you want to see, a simple project example is on github:

This is a little bit of indirection trickery and I don't recall the original source of this workaround.

If this error appears suddenly, it means the project is missing some frameworks. 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.

The other thing is if you added any classes in the compiled resources and removed that classes from the project then the error appears. The best thing to do is remove the classes from the compile resources(Build settings--> compile sources) which have removed from the project.

In my case i have added the admob classes in the project and compiled the project. In a later case i dont want to include admobs in my project so i deleted the references of the admob classes from my project. When this error occurred i deleted the .m class of my admob from compile resources solved this problem.

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

Another reason this could be happening is when you UPGRADE an SDK.

If you simply delete the group, and then drag and drop the new folder to project, the "Library Search Path" would have both the SDKs. To solve, simply delete the old SDK path.

I had used a CLGeocoder without adding a Core.Location Framework. Basically this error can mean multiple things. I hope this helps someone else.

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.

Came across this issue in Xcode 11, fix was changing the Minimum Deployment Target from 10.0 to 11.0, hope this helps someone :)