Xcode，重复符号 _main
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Xcode, Duplicate symbol _main
提问by huggie
I have duplicate symbol _main.
我有重复的符号_main。
The problem is it says "Duplicate symbol _main in /Users/.../i386/main-B9843B6026D6EFA4.o and /Users/.../i386/main-B9843B6026D6EFA4.o", the XXX and XXX are actually the same .o file. I don't know why it thinks it's duplicate symbol when it's the same .o?!
问题是它说“/Users/.../i386/main-B9843B6026D6EFA4.o和/Users/.../i386/main-B9843B6026D6EFA4.o中的重复符号_main”，XXX和XXX实际上是一样的。文件。我不知道为什么它认为它是相同的 .o 时它是重复的符号？！
Any help appreciated, thanks.
任何帮助表示赞赏，谢谢。
回答by huggie
Ah..I figure out it's that I have multiple entries under Targets/Compiled Sources ( in newer XCode it's under Build Phases/Compile Sources ). I removed them and the problem is solved. The multiple entry thing probably has to do with Git merge.
啊..我发现我在 Targets/Compiled Sources 下有多个条目（在较新的 XCode 中，它位于 Build Phases/Compile Sources 下）。我删除了它们，问题就解决了。多条目的事情可能与 Git 合并有关。
回答by dvkch
It appeared that in my case I was importing a .m file instead of its .h counterpart. Solved by editing
似乎在我的情况下，我正在导入一个 .m 文件而不是它的 .h 对应文件。通过编辑解决
#import "Tools.m"
into
进入
#import "Tools.h"
回答by Stefan
I also had this problem and it was caused by code I imported from another project. I did a grep for "int main" in my project directory:
我也有这个问题，它是由我从另一个项目导入的代码引起的。我在我的项目目录中为“int main”做了一个 grep：
grep -nr "int main" .
and found
并发现
./main.m:13:int main(int argc, char *argv[])
./IMPORTED_DIR/main.m:13:int main(int argc, char *argv[])
the IMPORTED_DIR contained the extra main.m that was causing the error for me
IMPORTED_DIR 包含导致我错误的额外 main.m
I removed that file from the Project -> Targets -> Build phases -> Compile sources list and then it compiled
我从项目 -> 目标 -> 构建阶段 -> 编译源列表中删除了该文件，然后编译
回答by Arbaz Shaikh
I was facing the same issue with using two third party framework. (AppLovin and Flurry) And I came to know that by removing "all_load" from "Other Linker Flags" in build settings.
我在使用两个第三方框架时遇到了同样的问题。（AppLovin 和 Flurry）我通过在构建设置中从“其他链接器标志”中删除“all_load”来了解这一点。
回答by Kas1a
I had the same problem opening a project, that was created with Xcode 4.0.2, with Xcode 4.1. I simply solved by clicking on "Modernize Project" (Editor/Modernize Project). This procedure automatically removed all duplicates.
我在打开一个项目时遇到了同样的问题，该项目是使用 Xcode 4.0.2 创建的，使用 Xcode 4.1。我只是通过单击“现代化项目”（编辑器/现代化项目）来解决。此过程会自动删除所有重复项。
回答by altosh
If still have a problem, try to search like this: "int main(", and remove those files except main.m
如果还有问题，尝试这样搜索："int main("，并删除除main.m之外的那些文件
回答by InvulgoSoft
Just got this problem myself, but after reading huggie's solution which did lead me on the right track, I was left a bit confused. So current solution in Xcode: Choose project, target -> build phases and click validate settings
我自己刚遇到这个问题，但在阅读了 Huggie 的解决方案后，它确实引导我走上了正确的道路，我有点困惑。所以Xcode中的当前解决方案：选择项目，目标->构建阶段并单击验证设置
Then Xcode will auto fix its own mistake. It is always nice when the tools tries to stop your progress ;)
然后Xcode会自动修复它自己的错误。当工具试图阻止你的进步时，总是很好;)
回答by Pierre-Francoys Brousseau
In my case, I declared an NSString in my constants file (imported by many classes) but forgot to define it as static!!
就我而言，我在我的常量文件（由许多类导入）中声明了一个 NSString 但忘记将其定义为静态！！
e.g. NSString* PARAMS = @"paramA";should be: static NSString* PARAMS = @"paramA";
例如 NSString* PARAMS = @"paramA";应该是：static NSString* PARAMS = @"paramA";
Reading the full error message allowed me to figure this out: "Duplicate symbol PARAMS". Don't be afraid and try to understand error messages! Sometimes they might even tell you exactly what you did wrong.
阅读完整的错误消息让我明白了这一点：“重复符号参数”。不要害怕并尝试理解错误消息！有时他们甚至可能会确切地告诉您您做错了什么。
回答by kraftydevil
You can get this for method names too!
您也可以为方法名称获取此信息！
I got duplicate symbol _runOnMainQueueWithoutDeadlockingafter adding DBCamera via CocoaPods and it was because both my category on NSObject (NSObject+Tools.h) and the GPUImage dependency file GPUImageOutput.m both had a method called 'runOnMainQueueWithoutDeadlocking'.
我duplicate symbol _runOnMainQueueWithoutDeadlocking在通过 CocoaPods 添加 DBCamera 之后得到了，这是因为我在 NSObject (NSObject+Tools.h) 上的类别和 GPUImage 依赖文件 GPUImageOutput.m 都有一个名为“runOnMainQueueWithoutDeadlocking”的方法。
I was fortunate enough to be able to remove my method from code because I wasn't actually using it anymore or anywhere.
我很幸运能够从代码中删除我的方法，因为我实际上不再使用它或在任何地方使用它。
It's probably what I deserve for putting a category on NSObject.
这可能是我在 NSObject 上放置一个类别的应得的。
回答by Fluffhead
In my case, I had imported another project, in order to utilize a library contained within. It resulted my project having two main.m files.
就我而言，我导入了另一个项目，以便利用其中包含的库。这导致我的项目有两个 main.m 文件。
This was even more confusing, since the error didn't show up until several builds later.
这更令人困惑，因为错误直到几次构建之后才出现。
