Xcode - command / developer / usr / bin / clang failed with exit code 1

Question

I am just starting to program and trying to learn C.

For my homework, I had to compile a program, and I am sure that my code is right, but whenever I try to test it or even try to run programs directly from a book, I get this error.

Ld "/Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Products/Debug/Lab 2.app/Contents/MacOS/Lab 2" normal x86_64 cd "/Users/BasirJamil/Desktop/Lab 2" setenv MACOSX_DEPLOYMENT_TARGET 10.7 /Developer/usr/bin/clang -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.7.sdk -L/Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Products/Debug -F/Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Products/Debug -filelist "/Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Intermediates/Lab 2.build/Debug/Lab 2.build/Objects-normal/x86_64/Lab 2.LinkFileList" -mmacosx-version-min=10.7 -framework Cocoa -o "/Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Products/Debug/Lab 2.app/Contents/MacOS/Lab 2" ld: duplicate symbol _main in /Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Intermediates/Lab 2.build/Debug/Lab 2.build/Objects-normal/x86_64/File.o and /Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2-fuyrgmtkjwgafzctwttcpwxptwox/Build/Intermediates/Lab 2.build/Debug/Lab 2.build/Objects-normal/x86_64/main.o for architecture x86_64 Command /Developer/usr/bin/clang failed with exit code 1 

Can someone please explain what the problem is, and how can I fix it without getting too technical (if possible)? Remember that I'm still new to programming

Thanks in advance

Answer 1

 ld: duplicate symbol _main in /Users/BasirJamil/Library/Developer/Xcode/DerivedData/Lab_2 

You have a variable (most likely) or a function defined more than once. Actually, you may have defined _main twice.

This helps to read the entire error message, not just the last line. :-)

Check your code.

Answer 2

You may also get this error if you accidentally included an implementation file rather than a header file. for example #import "MyClass.m" instead of #import "MyClass.h"

Answer 3

As indicated in other answers, this is because the linker finds more than one character, which is called the same ... in this case "_main". There are a number of reasons why this can happen (global variables / methods with the same name, global variables / methods defined - unlike declared - .. h files included more than once, etc.).

However, this is due to Xcode, the first thing you can check is your build phases. It is possible that the “Compile Sources” build phase is the same file more than once. In your case, this is probably "main.m".

Somehow this happened to me today after I added a lot of localized .xib files to my project and Xcode crashed.

Answer 4

I had this error, what am I doing, just look in "Build Phases" → "Compile Sources" and delete all duplicate files.

Answer 5

This error speaks of 2 functions with the same name - main were defined. According to your description that you are new to C, I think you can make the same stupid mistake as me. At the very beginning, I just dragged all the source files that I can download to study C, 2 projects, including LUA and http-parser, after which I started creating and running an Xcode project, then I came across the same error message that you sent on here.

Answer 6

I got the same error, I used the menu file-> open recent-> clear. after i did this, the error will disappear. There is nothing wrong with the code, just clear the story ...