Linker Command failed with exit code 1 (use -v to

问题:

I can't get rid of this error!

I have tried all sorts of things like clearing Derived Data(Preferences->Locations->click gray arrow to open Derived Data folder in Finder->right-click, move to trash), cleaning the project(CMD+Shift+K or Product->Clean), updating carthage and dependencies, checked other answers on StackOverflow (mostly adjustments in Build Settings/Phases), and recloned the app from github, etc.

The same project works on my collaborators computers..

EDIT: From the current top-rated answer, I was able to debug a little further...I am still not sure how to fix though. It looks like I have something in the project twice? I looked and can't find anything showing up twice!

Here's a picture of the log:

回答1:

i was facing same issue today in xcode 8 version 8.3.2

right click on issue --> reveal in log

then you are able to check what is causing that issue

回答2:

Maybe you installed a pod file and you are still trying to build from the .xcodeproj file instead of .xcworkspace

回答3:

the only thing that worked for me was to run pod deintegrate and pod install

回答4:

did you try a clean? cmd + shift + k

回答5:

Okay...So here is what solved my problem...

in App Delegate File:

#import "AppDelegate.h"
#import "DarkSkyAPI.h"
//#import "Credentials.h"

I had imported Credentials.h already in the DarkSkyAPI.m file in my project. Commenting out the extra import made the error go away!

Some things to mention and maybe help anyone in the future. @umairqureshi_6's answer did help me along the process, but did not solve it. He led to where I was able to dig out the info. I kept seeing AppDelegate and DarkSkyAPI files showing up in the error log and the information it was pulling from Credentials file was causing the error. I knew it had to be in one of these 3 files, so I immediately checked imports, because I remembered hearing that the .h carries all the imports from its .m file. Boom!

回答6:

I k now the question has already been answered. But if this helps somebody save some time : I had the same error. I checked everything to find a very small and stupid mistake from my side. I imported a core data ManagedObject custom file in a view controller of my project. I accidentally imported the .m file instead of the .h file which was causing the duplicate symbol in architecture error (linker command failed) because my .m file of properties class imports the .h file of core data class and hence causing duplicate import.

So just check if u have imported the right files before you try multiple solutions.!

回答7:

A lot of solutions are mentioned above. No one worked for me(but please try above first).

Select Project -> Select Target -> Linked Framework and Libraries -> Add all pod libraries . (remove if they exist in embedded binaries)

Now remove these from Framework Folder in left file explorer of xcode.

This solved my issue.

回答8:

Select the project-> Build Phase->Link Binary with libraries and add all pod libraries.

回答9:

I had the same problem using Carthage for dependencies.

Just go to Select Project -> Build Settings -> Search for Enable Bitcode -> If it is selected to Yes, select No.

That solved this problem for me.

回答10:

For any one having this issue with Flurry framework. This is what fixed my issue. For me the issue was that i had imported the following files but never used them. "libFlurryTVOS_9.2.3" "libFlurryWatch_9.2.3"

So all I had to do was go to project target settings and remove these 2 files from the "Linked framework and libraries" section and the problem was solved.

回答11:

I just had to do import Foundation!

I was using Kitura for Swift server side and kept forgetting this!

回答12:

Here is my problem and solution:

I removed two files from the source code using source tree(Version controller). After applying the diff, that contains the two classes I removed, Xcode didn't add it automatically. So I got linker error.

I manually added the files, by right click on group name and select "Add files to ". Now my error got resolved.

If anyone faced the linker error regarding class file, then try to add it manually.

回答13:

I had same problem.

The cause was that I declared same global variable in 2 files. So it was showing same error saying 2 duplicate symbols.

The solution was to remove those variables.

回答14:

Did not have this problem when I built and ran on my own device. Only had this problem with simulators. I just simply restarted my computer and ran it. It worked.

回答15:

Ok, I had the same problem just today and started googling it, when I came across this thread. I haven't finished reading the question when the answer struck my mind: I declared a class with an empty constructor

class MyClass{
    MyClass();

    void func_one(){
    // code
    }

    void func_two(){
    // code
    }

    ~MyClass(){
        cout << "Deleting object" << endl;
     }
};

Then I thought why not terminating (not sure if I'm correct with word selection here, but who cares) the constructor of my class with curly braces ({}). So I did:

class MyClass{
    MyClass(){}

    void func_one(){
    // code
    }

    void func_two(){
    // code
    }

    ~MyClass(){
        cout << "Deleting object" << endl;
     }
};

The problem eliminated, my code started working perfectly.

I know, the good practice is to investigate the issue and find the real cause, but this worked for me.