Clang error: duplicate symbol even after renaming symbol

Question

When i build my project I get a duplicate symbol error from clang.

    duplicate symbol _server in:
    /Users/ashwinjeyakumar/Library/Developer/Xcode/DerivedData/Hikes-emzsxfmokzerjhevoirupbsrobpm/Build/Intermediates/Hikes.build/Release-iphonesimulator/Hikes.build/Objects-normal/i386/HikeViewController.o
    /Users/ashwinjeyakumar/Library/Developer/Xcode/DerivedData/Hikes-emzsxfmokzerjhevoirupbsrobpm/Build/Intermediates/Hikes.build/Release-iphonesimulator/Hikes.build/Objects-normal/i386/HikeSearchResultsViewController.o
ld: 1 duplicate symbol for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

To debug this, I found where I defined server (it was a property) and removed it, replacing it with an info.plist entry. The error wouldn't go away though. I've tried:

renaming the Server entry in Info.Plist
'rm -rf' under /Users/[myusername]/Library/Developer/Xcode/DerivedData

A Shift+cmd+F search of my xcode project doesnt find any results for 'server' but the error still persists.

hmm i think this linker error might be a red herring. I have a "scene is unreachable due to lack of entry points" warning as well in the Issue Navigator. Maybe its not getting to the linker stage at all and that error is just a hangaround? — theraju, Dec 07 '12 at 05:46
nope, made the warning go away and this error still persists — theraju, Dec 07 '12 at 05:49

score 0 · Answer 1 · answered Dec 07 '12 at 06:32

0

I had an import "Constants.h" in my project. Constants.h had the following:

#ifndef Hikes_Constants_h
#define Hikes_Constants_h

#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
NSString *server = @"http://192.168.56.101:3000/";

#endif

The catch was that Constants.h was no longer in my XCode project, so searches for the symbol never gave results. I finally noticed i was importing a header that wasn't in the project.

answered Dec 07 '12 at 06:32

theraju

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As an aside, this pattern will generally give you the duplicate symbol problem if you include `Constants.h` in more than one .m file. The `#ifndef` statement is only effective once per .m file, so `Contants.h` (and notably your `server` definition) will be compiled twice, and you'll have duplicate symbols. You .h should use the `extern` construct. See http://stackoverflow.com/questions/538996/constants-in-objective-c. BTW, `FOUNDATION_EXPORT` is, effectively, just `extern`. – Rob Dec 08 '12 at 08:06

Clang error: duplicate symbol even after renaming symbol

1 Answers1