Xcode duplicate symbol _main - iphone

I'm getting the following error in Xcode 3.2.1 on Snow Leopard 10.6.2 whenever I try to compile any iPhone application generated by Appcelerator Titanium. However, the build error only appears when I select iPhone simulator on the architecture menu and if I select the iPhone device, I am able to run the app on my device .
Further more, the iPhone simulator launches successfully and executes the program directly from the Titanium environment which uses Xcode to build .
Why is this happening ?
ld: duplicate symbol _main in Resources/libTitanium.a(main.o) and /Users/prithviraj/Documents/project/Final/build/iphone/build/Final.build/Debug-iphonesimulator/Final.build/Objects-normal/i386/main.o
collect2: ld returned 1 exit status
Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

I can't tell you why this is happening, but I can suggest a workaround. When I commented out the entire contents of the main.m file that was generated for my Titanium project, I was able to compile successfully and run on the Simulator. Let me know if that works for you.

Check to see if you have multiple declarations of main function in your project.

I just spent a couple hours battling this one. It was because I was using the -all_load linker flag. If you are using that flag to get around the category bug, there are some other solutions -- see here.

I had a similar problem. A unit test class was accidentally included in my build. If you search your project for "main(" you'll probably find the duplicate functions.

This happened to me for 2 reasons:
1: Class A calls class B and both had imported the same class. Fix it by importing the class in .m file.
2: Two classes have a constant with the same name (even if the constant is defined in the .m file). Fix it by changing the name of the constants.

I had this problem because I define a file as such:
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
...
}
And also had a file main.m:
int main(int argc, char* argv[])
{
#autoreleasepool {
int retVal = UIApplicationMain(argc, argv, nil, #"AppDelegate");
return retVal;
}
}

Seems as though there are multiple ways to get into this state. Mine was different. I read a hint where you could drag from a .xib event selector into the .h implementation of your view controller and it would auto-gen your methods. It did - which was cool. I immediately started getting duplicate symbol errors - which was not cool.
I did not have time to dig deep into the linker to see what happened. I created a new view controller, copied the context of my old .xib into the new guy. Deleted the old .h, .m and .xib and built and it worked again. Very odd, very annoying time waste.
There is obviously some bug with this xcode "convenience".

I found this happened when i had an implementation file with a main function in it (say abc.m) and also had another main.m. Once I commented out the main function in abc.m, the project compiled successfully.

Based off what I can tell from these other answers, I'm going to need to be remove a bunch of main methods.
But to do that easily I first need to remove all the gd comments from my files because they are assiduously documented with comments at nearly every other line
This regular expression matches all C multi-line comments including their delimeters & may help you on your journey
/\*((?!\*/).)*\*/

I spent more than an hour in searching for a correct answer but nothing worked for me.
Finally the xcode it self telling something is duplicated, so go to that particular folder(in this case: /Users/prithviraj/Documents/project/Final/build/iphone/build/Final.build/Debug-iphonesimulator/Final.build/Objects-normal/i386/main.o) and delete all the files and also check same in your project whether that particular class/interface is declared twice if yes delete it.
After deletion clean and run the project.
It worked for me hope this helps(-_-).

Delete /Users/{username}/Library/Developer/Xcode/DerivedData folder and build again.

Related

Remote Swift Package: Xcode won't pause at this breakpoint because it has not been resolved [duplicate]

Shortly after updating to Xcode 13.2.1 I started seeing some weird behaviour of breakpoints. When I run an app (in a simulator) some of my breakpoints change their look and turn to dotted blue outlined. Xcode does not stop execution at these breakpoints although code has been compiled, loaded and executed. I checked it in Console by adding some prints.
When I hover over breakpoint Xcode shows a message:
Xcode won't pause at this breakpoint because it has not been resolved
Resolving it requires that:
The line at the breakpoint is compiled.
The compiler generates debug information that is not stripped out (check the Build Settings).
The library for the breakpoint is loaded.
All trivial solutions like reloading, reapplying breakpoints have not helped.
Did anybody else see something like this? Is there a way to solve it?
Screenshot for reference:
Ok, so in my particular case rebooting laptop has helped. All breakpoints are now good. But it would still be nice to know the cause of the problem.
Make sure that the file in which you are adding breakpoint is having correct target set in target membership.
Click on .m file in which you want to add breakpoint.
Select the file inspector.
Check if you have selected correct target for that file or not (check below image).
What worked for me, was to select the files, delete them with - Delete>Move To Trash - and then drag the files back from the trash to the project.
In my case the issue was happening, because class was not added to the target, which I was trying to build.
For my case somehow the code path was never invoked and very likely considered as dead code. The same thing applies when not adding the file to the target that you want to debug.
This can be the case or somehow debugger might not be able to resolve your breakpoint. The first thing in this case should be cleaning derived data and any caches.
But instead of recloning your repo you can just delete breakpoint config from the location described in this answer
In Xcode 14 the problem is much more prevalent and "consistent". I figured out one pattern where it always fails and how to mitigate it.
If you have a final class then breakpoints set on or inside a private method will have that issue. If you remove private from the method or final from the class the breakpoints will get resolved properly.
If tried everything and nothing worked I suggest the following:
Reclone your repo
This is what worked for me.
I just passed through this problem and the solution for me was recreating the files.
Note: The ones I was trying to originally breakpoint on were copied from another project. When I created the new files, even though their Identity and Type looked just the same (target membership, encoding, paths), for some reason breakpoints started to work again.
Note 2: When copying and pasting code to your new files (if done manually), migrated breakpoints - created in the older file - will continue to fail. Only the ones created in this new file will work properly.
Hope it helps.
My case
Working on framework development. Framework is injected into the sample app for development/run purpose. Breakpoints inside the framework won't work.
Fix
Just removing xcframework in sample app and replacing with framework.
Reason
xcframework are precompiled outside of the app, so lib isn't compiled when project is built and that's why breakpoints doesn't work.
For me reboot the Xcode, and it works~

Xcode builds app correctly, but unable to launch?

I'm running 10.10 with Xcode 6.1.
And I'm having trouble getting an app I wrote to work. After hours and hours I finally got it to build correctly after accidentally messing with something, but now I'm getting an error I don't have permission to view the file (if I open directly in Xcode) or if I try to open it from the Finder it says the App is damaged or corrupt and can't be open. If it matters it's written in Swift.
I've literally spent 6 hours on this (Just trying to get it to build) so any help would be greatly appreciated! Austen
Here's the Xcode workspace, project, files, and a build if anyone needs to take a look: http://pattersoncode.ca/ServerChecker.zip
There are a several issues here. I can't help you with all of them, but I can put you on the right path, at least.
The app won't launch because it wasn't built correctly. Specifically, there's not any actual binary executable in the built .app. You can see this by right-clicking on the built Server Checker.app and choosing Show Package Contents. In there is a Contents folder; open that. Inside that should be a folder called MacOS, in which your actual binary executable would be. But it's not there. This isn't really an app at all.
Reason is, you have a custom build rule for swift files that's making them not compile at all. Just remove that, you don't need it.
In Xcode, click on the top-level item of the project (it says something like ServerChecker, 1 target, OS X SDK 10.10). Then, under TARGETS, select ServerChecker. Click Build Rules. The thing that says "Swift source files using Script", that we don't need. Click the little X in the top-right corner, and click Delete when prompted. Now try to build again.
You'll get an error:
Undefined symbols for architecture x86_64:
"_main", referenced from:
implicit entry/start for main executable
Since you don't have a main.swift file, your app doesn't have a main entry point. In Swift, you must either provide an NSApplicationMain function (usually in main.swift), or you can declare your app delegate as NSApplicationMain, which has the effect of calling NSApplicationMain with your delegate class. I recommend the latter.
Open up AppDelegate.swift, and add #NSApplicationMain to your AppDelegate class. It should look like:
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
...
}
Now your app should build again. Right-click it and Show Package Contents to verify that there's actually an executable binary in there.
The app still won't run. It looks like on launch there's an error that a library couldn't be loaded.
Hopefully that helps you get moving, anyway. I really need to get back to work now. :)

Issue By Adding NON ARC Files to ARC iPhone Application?

I added add .h and .m files from an non ARC application to ARC iphone Application. I set -fno-objc-arc as compilerflag in build phases to these files. But when I try running this application after adding these files I am facing a problem. Application does not give any error is just shows failed once and stops the process of building.
I am confused and trying to understand what is the problem in this. After I delete these non ARC files, it is running normally.
First, you add the .h file but don't set any compile flag on it - your comment on this is a bit confusing - in fact your question and comments are confusing. So lets try to sort this out:
you added both the .m and the .h to your project - you can see them in the left pane
the .m file was added to the build phase of the desired target with a compile flag of -fno-objc-arc
Now it gets tricky, as your question is self contradictory:
1) you tried to build and the build failed. So then edit your post and provide the error messages.
2) the build succeeded, you ran the project, but it failed somehow. Problem is you don't tell us how it failed.
So, in addition to clarify your question, please note that if you add a non-ARC file to your project, that file must conform to certain conventions, which you can read about in the ARC docs (two very short articles, one from Apple, one from llvm). For instance, if you have a method in that file that starts with "init" or "create" then whatever object it returns must be retained not autoreleased.
I personally have used non-ARC files with an ARC project for a year now with no problems.
Just do the following thing:
Reset your simulator.
2 . Clear your Build
in your non arc file content remove the release,retain,autoreleasepool and auto release.
After build and run. hope it will work.

Cannot compile my app with few classes from the Google Mac Toolbox

UPDATE:
Here is more detailed compiler output:
So I am working on a simple app. I want to be able to do some encoding/decoding of strings, so I have added these three files from the Google Mac ToolBox to my project:
GTMDefines.h
GTMNSString+HTML.h
GTMNSString+HTML.m
Since my project uses ARC, I have added the files to the build phases and set the -fno-objc-arc flag so they don't compile with ARC. See the screenshot:
Now I go to my main view controller and add this line:
#import "GTMNSString+HTML.m"
And I try to compile my project. I get errors like these:
How can I solve this? I am new to iOS development so please explain well.
To get rid of the first two warnings (no rule to process file...) remove GTMDefines.h and GTMNSString+HTML.h from your "Compile sources". Only .m-files need to be there.
You never want to import .m files, even if it's technically possible! To get rid of your errors, change your import from
#import "GTMNSString+HTML.m"
to
#import "GTMNSString+HTML.h"

gcc-4.2 failed with exit code 1 iphone

I've seen this error with different variations on discussion forums but being a non programmer I'm not sure how to progress this.
Basically I have code which I found to help me with changing the background colors of cells on a grouped uitableview. The code introduced a line as such:
CGContextAddArcToPoint(c, minx, miny, midx, miny, ROUND_SIZE);
This gave an error indicated that it wasn't declared, so I added to my .h file the following under import uikit:
#import <UIKit/UIKit.h>
#define ROUND_SIZE 10
Now it shows that I have an error:
Command/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1 iphone
Some discussions talk about libraries but because I don't have a programming background I don't understand what to do. I also see that some people show a log output but I'm not sure where that comes from as I don't get any debug windows because I'm guessing it doesn't get that far. I simply click 'Build and Go' and I get this error in the Message window.
Any thoughts?
As you can see from the many different responses this error is caused by many different problems. Luckily, I have found the Meta Solution!
In xcode, right click the error line and choose "Open These Latest Results as Transcript Text File". This will open the real xcode output log, which should contain a better description of the error then was previously seen.
-Evan
I have gone through that same problem. There may be some file which has no refference . You can see that type of file in red letter. Remove that file.
You probably don't have the CoreGraphics.framework added to your frameworks list.
To make sure, click the "Frameworks" folder on Xcode. If the framework isn't listed on the table to the right, you'll need to add it by right-clicking the Frameworks folder, chooseing "Add Existing Framework..." and then choosing it from the list.
I've found the problem after seeing the Build Results window that Dave mentioned (thank you!!!). I had a different version of the same .h and .m file because I was testing with different code. I deleted the unnecessary files as it was seeing something in there as a duplicate.
The build was successful.
Thank you!
You can see the error message output from GCC by selecting "Build Results" from the "Build" menu or by pressing ⇧⌘B.
you have defined the same static constants!!!!
static NSString *kSectionTitleKey = #"sectionTitleKey";
static NSString *kSectionTitleKey = #"sectionTitleKey";
the problem is
nothing about the CoreGraphics.framework
Evans answer is the best thing you can do to find the exact reason of why you are having that error. In most cases, in my experience, is that there have been files that have been deleted but haven't been removed from the project.
This type of exit code error occures due to Any of your framework or Library overlap. so solve this problem check your error log and find out duplicate object symbols waring in log than you got actual file which is overlap in code.
Another fix to this problem that was the answer to my fix was that I had two classes with the same name. A webservices helper had created an Invoice class, and when I tried to add a file with that same name it didn't have any problems until I tried to compile.
So make sure all your classes have unique names :)
xcode build errors:
Unsupported compiler ‘GCC 4.2′ selected for architecture ‘i386′
Solution:
This can be caused by importing a project for a pre- iOS 5 SDK into a copy of xcode with iOS 5 SDK only.
To fix,
click your Project -> Build Settings. Then under Build Options, there is an entry for Compiler for C/C++/Objective-C. Choose Apple LLVM compiler 3.0.
When u create a file , u have to disable [uncheck] cocos2d libraries & then add the file. so that gcc-4.2 error will be rectified :) checkout!!!
This problem also arises when you rename the XIB file. You have to replace the old name with the new name in the xib files as well as in the navigation controller (if used).
For me, I found the solution above helpful....
"Open These Latest Results as Transcript Text File" which explained it couldn't find libGDataTouchStaticLib.a. I then had to build the static library for Gdata.xcodeproj (changing the active target > GdataTouchStaticLib) then had to manually add this file by dragging it to the targets > MYAPPNAME > Link Binary With Libraries. Build & Run.. All Good.
This issue could be because some libraries might be missing. Right click on the error line and click on "Open these results as transcript text files" and check the missing library.
I had the same problem, noticed that it was looking for a file in the wrong folder, essentially, don't store projects in folders with apostrophes in their name!
I had the same problem. The reason was, I had two int main(int argc, char *argv[]) functions.
I've gotten the same error and solved in a very strange way. Cleaning and rebuilding the project doesn't solve it but simply adding an empty line in ApplicationViewController.mm has forced the compiler to rebuild "something" and the error has gone by itself.
I just add that the same project compiles without error on iMac and failed on macBook.
I was getting this error on building a cocos2d project using xcode 4.3 on Lion. To fix this error, I followed the instructions here: http://www.mac.ph/cocos2d-templates-and-xcode-43
Here is one of the possible solutions:
Remove the .m(implementation) file import statement from the viewController class if it is included along with related .h(header) file.
Instead of including (by mistake)
#include "myClass.h"
#include "myClass.m"
Include only the required header file as:
#include "myClass.h"
Thanks,
Prodeveloper