我的一个朋友要求我尽可能多地用objective-c重写Box2D。我开始写作，到目前为止，当我构建项目时，我遇到了一些链接器错误，我遇到了以前的类似问题，但它没有帮助。我得到的错误是：
Ld /Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Products/Debug/Obj-Box2D normal x86_64
cd /Users/aizen-qa/Desktop/Obj-Box2D
setenv MACOSX_DEPLOYMENT_TARGET 10.9
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -L/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Products/Debug -F/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Products/Debug -filelist /Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Obj-Box2D.LinkFileList -mmacosx-version-min=10.9 -fobjc-arc -fobjc-link-runtime -framework Foundation -Xlinker -dependency_info -Xlinker /Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Obj-Box2D_dependency_info.dat -o /Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Products/Debug/Obj-Box2D
duplicate symbol _Ob2IsValid in:
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec3.o
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Mat22.o
duplicate symbol _Ob2InvSqr in:
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec3.o
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Mat22.o
duplicate symbol _Ob2IsValid in:
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec3.o
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec2.o
duplicate symbol _Ob2InvSqr in:
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec3.o
/Users/aizen-qa/Library/Developer/Xcode/DerivedData/Obj-Box2D-bwsosdvwkjzsscahpbqrbrnzlall/Build/Intermediates/Obj-Box2D.build/Debug/Obj-Box2D.build/Objects-normal/x86_64/Ob2Vec2.o
ld: 4 duplicate symbols for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
我读过类似的问题，并尝试了诸如检查导入不使用.m和重复变量名称等解决方案。但是我注意到向量的类具有相同的实例变量名称x，y，那么这是我是否收到错误的原因？
在多个实现文件中定义而不是声明数据元素。 这通常是因为包含的标头中的某些内容。
在引用 Ob2InvSqr 或 Ob2IsValid 的位置查找，并确保这些项目的存储只执行一次。
文件 Ob2Vec2.o 和 Ob2Vec3.o 包含相同的符号_Ob2InvSqr
这很可能意味着您在同一目标中同时拥有 Ob2Vec2.m 和 Ob2Vec3.m。
确保只有一个真正编译
我想你的一个头文件中_Ob2IsValid(...)了一个内联函数，但该函数没有内联（它太大了？
如果是这种情况，您可以像这样强制它内联：
__attribute__((always_inline)) inline void MyFunction(...) {}
或者只是让它出线
多亏了评论表MartinR，我才能够解决这个问题。这是因为我在.h文件中定义了一个函数，我将其包含在多个Objective-C类中。所以我所做的是将函数头放在 .h 文件中，并将其实现放在 .m 文件中。