如何利用make在ubuntu上解决主建筑工程的多重定义

Question

我只想使用makefile (不使用cmake )在linux上构建一个gtest项目。我在这里学习了本教程：

http://www.yolinux.com/TUTORIALS/Cpp-GoogleTest.html

但是获得了主要错误的多个定义--见下文。

我上的是ubuntu v20.04

angus@angus-VirtualBox:~/Documents/code/gtest_make_only/test/src$ uname -a 5.11.0-38-通用#42~20.04.1-Ubuntu 9月28日20:41:07 UTC 2021 x86_64 GNU/Linux

我安装了这样的设备：

git clone https://github.com/google/googletest.git
mkdir build
cd build
sudo snap install cmake --classic
cmake .. -DBUILD_GMOCK=OFF
make
sudo make install

如果我现在看看我的系统

/usr/local/include -带有头文件的gtest目录

/usr/local/lib -包含libgtest.a和libgtest_main.a

我在示例中修改了Makefile，如下所示：

CXX = g++
CXXFLAGS = -g -L/usr/local/lib -lgtest -lgtest_main -lpthread
INCS = -I./ -I../../src -I/usr/local/include
OBJS = ../../src/Addition.o Addition_Test.o ../../src/Multiply.o Multiply_Test.o

testAll: $(OBJS)
    $(CXX) $(CXXFLAGS) $(INCS) -o testAll  Main_TestAll.cpp $(OBJS)

.cpp.o:
    $(CXX) $(CXXFLAGS) -c $< -o $@ $(INCS)

clean:
    rm testAll *.o testAll.xml

我还必须整理代码示例--比如代码中有加法的地方--必须更改为Addition.hpp，即文件名。

下面的生成错误。怎么解决这个问题？

我确实尝试了从Makefile中删除-lgtest_main，但随后得到了错误：

/home/angus/Documents/code/gtest_make_only/test/src/Main_TestAll.cpp:5: undefined reference to `testing::InitGoogleTest(int*, char**)'

生成错误：

angus@angus-VirtualBox:~/Documents/code/gtest_make_only/test/src$ make
g++ -g -L/usr/local/lib -lgtest -lgtest_main -lpthread -c Multiply_Test.cpp -o Multiply_Test.o -I./ -I../../src -I/usr/local/include
g++ -g -L/usr/local/lib -lgtest -lgtest_main -lpthread -I./ -I../../src -I/usr/local/include -o testAll  Main_TestAll.cpp ../../src/Addition.o Addition_Test.o ../../src/Multiply.o Multiply_Test.o
/usr/bin/ld: /tmp/cc4xkhF1.o: in function `RUN_ALL_TESTS()':
/home/angus/Documents/code/gtest_make_only/test/src/Main_TestAll.cpp:4: multiple definition of `main'; /usr/local/lib/libgtest_main.a(gtest_main.cc.o):gtest_main.cc:(.text+0x0): first defined here
/usr/bin/ld: /usr/local/lib/libgtest_main.a(gtest_main.cc.o): in function `main':
gtest_main.cc:(.text+0x3a): undefined reference to `testing::InitGoogleTest(int*, char**)'
/usr/bin/ld: /usr/local/lib/libgtest_main.a(gtest_main.cc.o): in function `RUN_ALL_TESTS()':
gtest_main.cc:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0x9): undefined reference to `testing::UnitTest::GetInstance()'
/usr/bin/ld: gtest_main.cc:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0x11): undefined reference to `testing::UnitTest::Run()'
/usr/bin/ld: /tmp/cc4xkhF1.o: in function `main':
/home/angus/Documents/code/gtest_make_only/test/src/Main_TestAll.cpp:5: undefined reference to `testing::InitGoogleTest(int*, char**)'
/usr/bin/ld: Addition_Test.o: in function `AdditionTest_twoValues_Test::TestBody()':
/home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:20: undefined reference to `testing::Message::Message()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:20: undefined reference to `testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:20: undefined reference to `testing::internal::AssertHelper::operator=(testing::Message const&) const'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:20: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:21: undefined reference to `testing::Message::Message()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:21: undefined reference to `testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:21: undefined reference to `testing::internal::AssertHelper::operator=(testing::Message const&) const'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:21: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:20: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:21: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: Addition_Test.o: in function `__static_initialization_and_destruction_0(int, int)':
/home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:16: undefined reference to `testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, testing::internal::CodeLocation, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)'
/usr/bin/ld: Addition_Test.o: in function `testing::internal::SuiteApiResolver<AdditionTest>::GetSetUpCaseOrSuite(char const*, int)':
/usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::IsTrue(bool)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: Addition_Test.o: in function `testing::internal::SuiteApiResolver<AdditionTest>::GetTearDownCaseOrSuite(char const*, int)':
/usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::IsTrue(bool)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: Addition_Test.o: in function `testing::AssertionResult testing::internal::CmpHelperEQ<int, int>(char const*, char const*, int const&, int const&)':
/usr/local/include/gtest/gtest.h:1549: undefined reference to `testing::AssertionSuccess()'
/usr/bin/ld: Addition_Test.o: in function `testing::AssertionResult testing::internal::CmpHelperEQFailure<int, int>(char const*, char const*, int const&, int const&)':
/usr/local/include/gtest/gtest.h:1532: undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
/usr/bin/ld: Addition_Test.o: in function `AdditionTest::~AdditionTest()':
/home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:5: undefined reference to `testing::Test::~Test()'
/usr/bin/ld: Addition_Test.o:(.data.rel.ro._ZTI12AdditionTest[_ZTI12AdditionTest]+0x10): undefined reference to `typeinfo for testing::Test'
/usr/bin/ld: Addition_Test.o: in function `AdditionTest::AdditionTest()':
/home/angus/Documents/code/gtest_make_only/test/src/Addition_Test.cpp:5: undefined reference to `testing::Test::Test()'
/usr/bin/ld: Multiply_Test.o: in function `MultiplyTest_twoValues_Test::TestBody()':
/home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:18: undefined reference to `testing::Message::Message()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:18: undefined reference to `testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:18: undefined reference to `testing::internal::AssertHelper::operator=(testing::Message const&) const'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:18: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:19: undefined reference to `testing::Message::Message()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:19: undefined reference to `testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:19: undefined reference to `testing::internal::AssertHelper::operator=(testing::Message const&) const'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:19: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:18: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: /home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:19: undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
/usr/bin/ld: Multiply_Test.o: in function `__static_initialization_and_destruction_0(int, int)':
/home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:14: undefined reference to `testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, testing::internal::CodeLocation, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)'
/usr/bin/ld: Multiply_Test.o: in function `testing::internal::SuiteApiResolver<MultiplyTest>::GetSetUpCaseOrSuite(char const*, int)':
/usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::IsTrue(bool)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:527: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: Multiply_Test.o: in function `testing::internal::SuiteApiResolver<MultiplyTest>::GetTearDownCaseOrSuite(char const*, int)':
/usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::IsTrue(bool)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: /usr/local/include/gtest/internal/gtest-internal.h:548: undefined reference to `testing::internal::GTestLog::~GTestLog()'
/usr/bin/ld: Multiply_Test.o: in function `MultiplyTest::~MultiplyTest()':
/home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:5: undefined reference to `testing::Test::~Test()'
/usr/bin/ld: Multiply_Test.o:(.data.rel.ro._ZTI12MultiplyTest[_ZTI12MultiplyTest]+0x10): undefined reference to `typeinfo for testing::Test'
/usr/bin/ld: Multiply_Test.o: in function `MultiplyTest::MultiplyTest()':
/home/angus/Documents/code/gtest_make_only/test/src/Multiply_Test.cpp:5: undefined reference to `testing::Test::Test()'
collect2: error: ld returned 1 exit status
make: *** [Makefile:7: testAll] Error 1

Answer 1

你的命令行都错了。

库规范应该遵循源文件和对象文件。正确的行应该如下所示：

g++ -g -I./ -I../../src -o testAll  Main_TestAll.cpp ../../src/Addition.o Addition_Test.o ../../src/Multiply.o Multiply_Test.o -lgtest_main -lgtest -lpthread 

有关解释，请参见这篇博客文章。