title: How to fix Command /Developer/usr/bin/clang failed with exit code 1?
body: <p>Hi there I am new to C programming and have been using Xcode to write my simple CS HW.  They have been working fine until a couple weeks ago when I keep getting this error code below.  I went ahead and try to run some old programs that I know for sure works but still get this error.  I looked everywhere and can't find the solution.  If you have a solution please help.  Although I would love a specific answer, I am very new to this and would hope you take that into consideration when explaining.  Thank you very much.  </p>
  
  <pre><code>Ld /Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Products/Debug/Test normal x86_64
      cd /Users/------/Desktop/Test
      setenv MACOSX_DEPLOYMENT_TARGET 10.7
      /Developer/usr/bin/clang -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.7.sdk -L/Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Products/Debug -F/Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Products/Debug -filelist /Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/Test.LinkFileList -mmacosx-version-min=10.7 -o /Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Products/Debug/Test
  
  ld: duplicate symbol _main in /Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/HW4.o and /Users/------/Library/Developer/Xcode/DerivedData/Test-gehcspqxloqgaahbdyjslulobzys/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/HW3.o for architecture x86_64
  Command /Developer/usr/bin/clang failed with exit code 1
  </code></pre>
  
  <p>what is this error code?</p>
  
  <pre><code>Command /Developer/usr/bin/clang failed with exit code 1
  </code></pre>