我正在Xcode 5中制作原型，但有很多错误，所以我决定回到绘图板并开始一个新项目。当我创建新项目时，它有一个叮当错误，就像上一个一样。
这是它所说的
Ld /Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Products/Debug-iphonesimulator/Trivia in a Jar.app/Trivia in a Jar normal i386
cd "/Users/jaydenkelly/Desktop/Trivia in a Jar"
setenv IPHONEOS_DEPLOYMENT_TARGET 7.0
setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator7.0.sdk -L/Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Products/Debug-iphonesimulator -F/Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Products/Debug-iphonesimulator -filelist /Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Intermediates/Trivia in a Jar.build/Debug-iphonesimulator/Trivia in a Jar.build/Objects-normal/i386/Trivia in a Jar.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=7.0 -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker /Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Intermediates/Trivia in a Jar.build/Debug-iphonesimulator/Trivia in a Jar.build/Objects-normal/i386/Trivia in a Jar_dependency_info.dat -o /Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Products/Debug-iphonesimulator/Trivia in a Jar.app/Trivia in a Jar
duplicate symbol _i in:
/Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Intermediates/Trivia in a Jar.build/Debug-iphonesimulator/Trivia in a Jar.build/Objects-normal/i386/Game.o
/Users/jaydenkelly/Library/Developer/Xcode/DerivedData/Trivia_in_a_Jar-cqzkvawfethhydcaldqtecmwfkkm/Build/Intermediates/Trivia in a Jar.build/Debug-iphonesimulator/Trivia in a Jar.build/Objects-normal/i386/Test.o
ld: 1 duplicate symbol for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
看起来你有两个全局变量_i，一个在Game.m，一个在Test.m文件中。如果您不需要它们在整个程序中可见，只需将它们设为static即可。