是什么导致 macOS Mojave 上的 GoogleTest 链接错误？ [复制]答案

【问题标题】：What is causing GoogleTest Link Error on macOS Mojave? [duplicate]是什么导致 macOS Mojave 上的 GoogleTest 链接错误？ [复制]
【发布时间】：2020-02-29 00:41:10
【问题描述】：

我不确定我是否有需要向 cmake 附加参数的问题，或者我自己的 Makefile 有问题。我正在尝试构建和安装 googletest 以用于我的一个项目。我在 macOS mojave 上运行，通过 Homebrew 安装了 cmake。要安装 googletest，我做了以下操作：

git clone https://github.com/google/googletest
cd googletest
mkdir build
cd build
cmake ..
make
make install

我编译我的源文件和测试文件。以下是 Makefile 生成的用于编译名为 Point2d.cpp 的文件的示例命令：

clang++ -arch x86_64 -c -std=c++11 -stdlib=libc++ -O2 -I /usr/local/include -c -o ../build/core/Point2d.o core/Point2d.cpp

然后我尝试链接我所有的目标文件。这是由 makefile 生成的命令（其中 main.o 是包含运行测试的主要函数的目标文件）：

clang++ -arch x86_64 ../build/core/Point2d.o ../build/PointTest.o ../build/main.o -o ../bin/test -L /usr/local/lib

导致链接错误：

Undefined symbols for architecture x86_64:
  "testing::InitGoogleTest(int*, char**)", referenced from:
      _main in main.o
  "testing::Test::SetUp()", referenced from:
      vtable for Point2dTests_Constructors_Test in PointTest.o
  "testing::Test::TearDown()", referenced from:
      vtable for Point2dTests_Constructors_Test in PointTest.o
  "testing::Test::Test()", referenced from:
      testing::internal::TestFactoryImpl<Point2dTests_Constructors_Test>::CreateTest() in PointTest.o
  "testing::Test::~Test()", referenced from:
      Point2dTests_Constructors_Test::~Point2dTests_Constructors_Test() in PointTest.o
      Point2dTests_Constructors_Test::~Point2dTests_Constructors_Test() in PointTest.o
  "testing::Message::Message()", referenced from:
      Point2dTests_Constructors_Test::TestBody() in PointTest.o
  "testing::UnitTest::GetInstance()", referenced from:
      _main in main.o
  "testing::UnitTest::Run()", referenced from:
      _main in main.o
  "testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)", referenced from:
      Point2dTests_Constructors_Test::TestBody() in PointTest.o
  "testing::internal::AssertHelper::~AssertHelper()", referenced from:
      Point2dTests_Constructors_Test::TestBody() in PointTest.o
  "testing::internal::GetTestTypeId()", referenced from:
      __GLOBAL__sub_I_PointTest.cpp in PointTest.o
  "testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, testing::internal::CodeLocation, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)", referenced from:
      __GLOBAL__sub_I_PointTest.cpp in PointTest.o
  "testing::internal::GetBoolAssertionFailureMessage(testing::AssertionResult const&, char const*, char const*, char const*)", referenced from:
      Point2dTests_Constructors_Test::TestBody() in PointTest.o
  "testing::internal::IsTrue(bool)", referenced from:
      testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
      testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
  "testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)", referenced from:
      testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
      testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
  "testing::internal::GTestLog::~GTestLog()", referenced from:
      testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
      testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
  "testing::internal::AssertHelper::operator=(testing::Message const&) const", referenced from:
      Point2dTests_Constructors_Test::TestBody() in PointTest.o
  "typeinfo for testing::Test", referenced from:
      typeinfo for Point2dTests_Constructors_Test in PointTest.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [../bin/test] Error 1
make: *** [test] Error 2

【问题讨论】：

你需要告诉编译器你要链接google测试库。将-lgtest（或任何库名称）添加到您的链接阶段。
@AlexDenisov "make install" for googletest 将库添加到 /usr/local/lib 目录...这就是为什么在链接期间我指定 -L /usr/local/lib。这不会有那种效果吗？
-L 告诉链接器/编译器在哪里查找库，但您还应该使用 -l 标志告诉它要链接哪些库
解决了。我是如此接近..但到目前为止大声笑。我会发布参考您的评论的答案。非常感谢。

标签： c++ c++11 cmake clang googletest

【解决方案1】：

解决了。请参阅@AlexDenisov 发布的问题的cmets

【讨论】：