在mac上构建Google测试时出现链接错误(命令行)

Question

我目前正在尝试构建一些使用Google C++测试框架的测试代码，但我一直收到一个错误，说明

ld：警告：在/usr/local/lib/libgtest.dylib中，文件是为不受支持的文件格式构建的，该格式不是链接的体系结构（i386）

我试图让问题尽可能简单：

我有一个主要功能cmtest.cc

#include <gtest/gtest.h>
/** Main entry point */
int main(int argc, char**argv, char**envArg)
{
    testing::InitGoogleTest(&argc, argv);
    return(RUN_ALL_TESTS());
}

真正基本的测试代码CrazyTest.cc

#include <gtest/gtest.h>
TEST(CrazyTest, one) {
    EXPECT_EQ(2, 2);
}

我使用以下命令来构建gtest和我的测试代码。

g++ -o CrazyTest.o -c -Wall -Werror=non-virtual-dtor -pipe -std=c++98 -fno-rtti -fno-exceptions -fno-strict-aliasing -Wno-deprecated -g -arch i386 -arch x86_64 -mmacosx-version-min=10.5.4 -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_HAS_RTTI=0 -I/opt/gtest-1.6.0/include CrazyTest.cc
g++ -o cmtest.o -c -Wall -Werror=non-virtual-dtor -pipe -std=c++98 -fno-rtti -fno-exceptions -fno-strict-aliasing -Wno-deprecated -g -arch i386 -arch x86_64 -mmacosx-version-min=10.5.4 -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_HAS_RTTI=0 -I/opt/gtest-1.6.0/include cmtest.cc
g++ -o gtest-all.o -c -Wall -Werror=non-virtual-dtor -pipe -std=c++98 -fno-rtti -fno-exceptions -fno-strict-aliasing -Wno-deprecated -g -arch i386 -arch x86_64 -mmacosx-version-min=10.5.4 -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_HAS_RTTI=0 -I/opt/gtest-1.6.0 -I/opt/gtest-1.6.0/include /opt/gtest-1.6.0/src/gtest-all.cc
ar rc libgtest.a gtest-all.o
ranlib libgtest.a
g++ -o cmtest -arch i386 -arch x86_64 -mmacosx-version-min=10.5.4 CrazyTest.o cmtest.o -lstdc++ -lgtest

最后一个构建步骤给了我以下错误，我无法找出原因。我能够在其他操作系统上进行实际的测试（而不是显示的简单测试），macOS（豹子）给我带来了问题。

 ld: warning: in /usr/local/lib/libgtest.dylib, file was built for unsupported file format which is not the architecture being linked (i386)
Undefined symbols for architecture i386:
  "testing::Test::~Test()", referenced from:
      CrazyTest_one_Test::~CrazyTest_one_Test()in CrazyTest.o
      CrazyTest_one_Test::~CrazyTest_one_Test()in CrazyTest.o
  "testing::internal::AssertHelper::~AssertHelper()", referenced from:
      CrazyTest_one_Test::TestBody()      in CrazyTest.o
  "testing::Test::Test()", referenced from:
      CrazyTest_one_Test::CrazyTest_one_Test()in CrazyTest.o
  "testing::internal::GetTestTypeId()", referenced from:
      __static_initialization_and_destruction_0(int, int)in CrazyTest.o
  "testing::Test::TearDown()", referenced from:
      vtable for CrazyTest_one_Testin CrazyTest.o
  "testing::internal::EqFailure(char const*, char const*, testing::internal::String const&, testing::internal::String const&, bool)", referenced from:
      testing::AssertionResult testing::internal::CmpHelperEQ<int, int>(char const*, char const*, int const&, int const&)in CrazyTest.o
  "testing::UnitTest::GetInstance()", referenced from:
      _main in cmtest.o
  "testing::internal::IsTrue(bool)", referenced from:
      testing::internal::scoped_ptr<std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> > >::reset(std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >*)in CrazyTest.o
      testing::internal::scoped_ptr<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >::reset(std::basic_string<char, std::char_traits<char>, std::allocator<char> >*)in CrazyTest.o
  "testing::UnitTest::Run()", referenced from:
      _main in cmtest.o
  "testing::internal::AssertHelper::operator=(testing::Message const&) const", referenced from:
      CrazyTest_one_Test::TestBody()      in CrazyTest.o
  "testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)", referenced from:
      CrazyTest_one_Test::TestBody()      in CrazyTest.o
  "testing::AssertionSuccess()", referenced from:
      testing::AssertionResult testing::internal::CmpHelperEQ<int, int>(char const*, char const*, int const&, int const&)in CrazyTest.o
  "testing::Test::SetUp()", referenced from:
      vtable for CrazyTest_one_Testin CrazyTest.o
  "testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)", referenced from:
      __static_initialization_and_destruction_0(int, int)in CrazyTest.o
  "testing::InitGoogleTest(int*, char**)", referenced from:
      _main in cmtest.o
ld: symbol(s) not found for architecture i386
collect2: ld returned 1 exit status
lipo: can't open input file: /var/tmp//ccZQiF8k.out (No such file or directory)

我已经为我所构建的所有东西定义了-arch i386和-arch x86_64，所以我无法弄清楚我错过了什么。我在Mac电脑上不怎么编程，这个特殊的问题让我陷入了困境。

任何建议都会很有帮助。

Answer 1

找到解决方案。事实证明，使用的构建指令是正确的，问题是在执行构建的计算机上，另一位开发人员使用Google Test Framework 1.5做了一些工作，他们在编译器搜索路径中的计算机上安装了库。这导致编译器首先找到另一个未使用多个体系结构选项编译的库。

Answer 2

使用相同的编译器（-flags）编译gtest和您的项目

如果您使用Apple g++编译gtest，同时使用例如自制软件安装gcc，则链接到gtest将导致此错误。这正是谷歌建议在项目中集成静态链接的gtest，而不是使用预编译的二进制文件的原因。

Answer 3

如果gmock和gtest不同步，您可能也会遇到这个问题。我在gmock-1.6.0和gtest-1.7.0中也有类似的构建错误：

../../../third_party/gmock/build/libgmock.a(gmock-all.cc.o): In function `testing::internal::ParseGoogleMockFlagValue(char const*, char const*, bool)':
gmock-all.cc:(.text+0x3b5c): undefined reference to `testing::internal::String::Format(char const*, ...)'
../../../third_party/gmock/build/libgmock.a(gmock-all.cc.o): In function `testing::internal::String::operator==(char const*) const':
gmock-all.cc:(.text._ZNK7testing8internal6StringeqEPKc[testing::internal::String::operator==(char const*) const]+0x33): undefined reference to `testing::internal::String::Compare(testing::internal::String const&) const'
collect2: ld returned 1 exit status

同时切换到1.7.0或同时切换到1.6.0解决了问题。