入口点 (_main) 未定义 xcode 6

Question

I can't for the life of me find a solution to this! I'm using Swift. All of a sudden I get this error:

Undefined symbols for architecture i386:
  "_main", referenced from:
     implicit entry/start for main executable
ld: symbol(s) not found for architecture i386

It doesn't matter what simulator/device I try to run for, I still get it:

Undefined symbols for architecture x86_64:
  "_main", referenced from:
     implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64

What is this?! I've almost removed everything from my project. Ie all frameworks and everything. It's still there.

Please help me

Answer 1

Have this in your AppDelegate.swift:

import UIKit

@UIApplicationMain

Answer 2

Another cause (not for you but for others searching for an answer) is that AppDelegate.swift is for some reason not included in the app target. I don't know why that would happen-- I assume it was user error on my part-- but without that you'll get this error, and the cause isn't obvious. Make sure the checkbox for the file is checked in the app target.

Answer 3

我有同样的问题，但我只是忘了把@UIApplicationMain放在 AppDelegate.swift 的顶部

Answer 4

我的问题是：“main.m”已删除项目。

Answer 5

My problem was the following. I had 2 AppDelegate files. The original one that I wanted to delete, and another one I wanted to add. I first added the new one to the project and then deleted the old one. Following this order created a linker error. It worked when I deleted the new one and added it again to the project. Cheers

Answer 6

我有同样的错误，发现 main.m 包含在项目文件列表中，但没有在目标成员列表中打勾。

Answer 7

Some of the classes and frameworks(like FB SDK) are not ticked like in the picture. So, I manually ticked(only .m files and frameworks) in all classes and frameworks in the Project Navigator.

Answer 8

If this error come you have two problems:

1. you comment out (with // ) the appleDelegate.swift , you should uncomment it
2. you miss the appleDelegate.swift in your project

Answer 9

要在 Xcode 12.3 中解决此问题，请将@main属性添加到AppDelegate 。