这是一个非常简单的C++程序.
// test.h class Test { public: Test(); }; // test.cpp #include "test.h" Test::Test() { // do something } // main.cpp #include "test.h" int main() { Test t; return 0; }
我试图使用此命令行在OSX上使用clang ++编译它,我收到此错误:
[test]$ clang++ main.cpp -o main Undefined symbols for architecture x86_64: "Test::Test()", referenced from: _main in main-017149.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
这是使用-v
开关的编译:
[test]$ clang++ main.cpp -o main -v Apple LLVM version 6.0 (clang-600.0.34.4) (based on LLVM 3.5svn) Target: x86_64-apple-darwin13.2.0 Thread model: posix "/Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.9.0 -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name main.cpp -mrelocation-model pic -pic-level 2 -mdisable-fp-elim -masm-verbose -munwind-tables -target-cpu core2 -target-linker-version 241 -v -resource-dir /Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0 -stdlib=libc++ -fdeprecated-macro -fdebug-compilation-dir /Users/ramin/projects/algorithm_examples/test -ferror-limit 19 -fmessage-length 139 -stack-protector 1 -mstackrealign -fblocks -fobjc-runtime=macosx-10.9.0 -fencode-extended-block-signature -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -vectorize-slp -o /var/folders/z5/hyt30v7d7t7_w1xfpdgqp05w0000gn/T/main-d17898.o -x c++ main.cpp clang -cc1 version 6.0 based upon LLVM 3.5svn default target x86_64-apple-darwin13.2.0 ignoring nonexistent directory "/usr/include/c++/v1" #include "..." search starts here: #include <...> search starts here: /Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1 /usr/local/include /Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/include /Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include /usr/include /System/Library/Frameworks (framework directory) /Library/Frameworks (framework directory) End of search list. "/Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld" -demangle -dynamic -arch x86_64 -macosx_version_min 10.9.0 -o main /var/folders/z5/hyt30v7d7t7_w1xfpdgqp05w0000gn/T/main-d17898.o -lc++ -lSystem /Applications/Xcode6-Beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/lib/darwin/libclang_rt.osx.a Undefined symbols for architecture x86_64: "Test::Test()", referenced from: _main in main-d17898.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
我究竟做错了什么?
main.cpp
包括test.h
; 它不包括test.cpp
.您可以通过将它们指定为输入来同时编译和链接它们:
[test]$ clang++ main.cpp test.cpp -o main