Apple Mach-O Linker Error when compiling for devic

Question

I've just upgraded to xcode 4.0 and I can no longer deploy to iPhone, I get a Apple Mach-O Linker Error, it still works for the simulator though.

    Ld /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Intermediates/iParcel.build/Debug-iphoneos/iParcel.build/Objects-normal/armv7/iParcel normal armv7
    cd /Users/yveswheeler/iParcel
    setenv IPHONEOS_DEPLOYMENT_TARGET 3.2
    setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/g++-4.2 -arch armv7 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk -L/Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos -F/Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos -filelist /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Intermediates/iParcel.build/Debug-iphoneos/iParcel.build/Objects-normal/armv7/iParcel.LinkFileList -dead_strip -all_load -ObjC -lxml2 -miphoneos-version-min=3.2 -framework UIKit -framework CoreGraphics -framework QuartzCore /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Core.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Network.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Style.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UI.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UICommon.a /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UINavigator.a -framework AddressBook -lz.1.2.3 -framework Foundation -framework CFNetwork -framework MobileCoreServices -framework SystemConfiguration -framework MessageUI -framework AudioToolbox -o /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Intermediates/iParcel.build/Debug-iphoneos/iParcel.build/Objects-normal/armv7/iParcel

arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Core.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Network.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20Style.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UI.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UICommon.a: No such file or directory
arm-apple-darwin10-g++-4.2.1: /Users/yveswheeler/Library/Developer/Xcode/DerivedData/iParcel-fkeqjcjcbbhjwhdssjptkdxzzzxh/Build/Products/Debug-iphoneos/libThree20UINavigator.a: No such file or directory
Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/g++-4.2 failed with exit code 1

Answer 1

I had exactly the same problem just because I had two same constants in different classes. You also can have this problem if you import .m file not .h file

Answer 2

This did a trick for me:

Go to

1) Products > clean

2) Windows > Projects

3) Select your project and click on "Delete" derived Data

4) Products > Build

Answer 3

Bizarre error. For me, I just cleaned and restarted Xcode and the problem went away.

Answer 4

I just try to create a category class file and got this weird issue..and finally....

Wrong way to create category class that causes the issue:

New File -> Cocoa Touch -> Objective-C class, then I modified the name of files to Category Class like name.. (i.e. OriginalClass_CategoryName.h/m to OriginalClass+CategoryName.h/m, and also modified the contents in the file).

Right way here:

New File -> Cocoa Touch -> Objective-C category, and it'll auto generate files (OriginalClass+CategoryName.h/m).

Oh, how stupid I am!!

Answer 5

One possibility: Turn on "Dead code stripping" in the Xcode 4 build settings.

Another possibility: It could be that you switched to using LLVM for some framework that was previously using GCC. Moving back to GCC (or LLVM GCC) may get rid of those warnings.

Answer 6

Re: Problem as outlined in title:

Just in case anyone else missed the obvious...

I came across this error after installing a new version of Xcode4 and dragging existing files into a new project. I had failed to spot that the 'add to targets' checkbox was left unchecked in the 'Choose options for adding files:' dialog. Correcting my omission in Targets>Build Phases>Compile Sources solved the problem.