undefined reference to testing::internal::EqFailure in gtest

Question

I am trying to do a test for a function using GoogleTest an now it is not finding anymore the EqFailure thing:

/usr/include/gtest/gtest.h:1337: undefined reference to `testing::internal::EqFailure(char const*, char const*, testing::internal::String const&, testing::internal::String const&, bool)'

I am writing the test like this:

test_file.cpp:

#include <gtest/gtest.h>

#include "tools/CMorphology.hpp"

TEST(erode_Morph, crossKernel_Morph)
{
  // initialize matrix to be eroded
  cv::Mat matrix = (cv::Mat_<uchar>(5, 5) << 1, 1, 1, 1, 1,
                                             1, 1, 0, 1, 1,
                                             1, 1, 1, 1, 1,
                                             1, 0, 1, 1, 1,
                                             1, 1, 1, 1, 1
            );
  // initialize the cross kernel
  cv::Mat kernel = cv::getStructuringElement(cv::MORPH_CROSS, cv::Size(3, 3));
  // initialize the vector expected as output
  cv::Mat verMat = (cv::Mat_<uchar>(5, 5) << 1, 1, 0, 1, 1,
                                             1, 0, 0, 0, 1,
                                             1, 0, 0, 1, 1,
                                             0, 0, 0, 1, 1,
                                             1, 0, 1, 1, 1);

  // call erode(...)
  Morphology morphology;
  cv::Mat matrixOut;
  morphology.erode(matrix, kernel, matrixOut);

  for (int i = 0; i < matrixOut.rows; i++)
  {
    for (int j = 0; j < matrixOut.rows; j++)
    {
      EXPECT_EQ(matrixOut.ptr<uchar>(i)[j], verMat.ptr<uchar>(i)[j]);
    }
  }
}

I am using OpenCV and if needed, I'll post the other files.

CMake file is here:

cmake_minimum_required(VERSION 2.8)

set(EXECUTABLE_NAME lpdetect)
project(${EXECUTABLE_NAME})

option(DEBUG "Display images for each step" OFF)

if (DEBUG)
        set(CMAKE_CXX_FLAGS "-g -Wall -Wno-unknown-pragmas -Wno-reorder -Wno-sign-compare -Wno-switch -std=gnu++11 -DDISPLAY_IMGS -DBOOST_LOG_DYN_LINK")
else()
        set(CMAKE_CXX_FLAGS "-g -Wall -Wno-unknown-pragmas -Wno-reorder -Wno-sign-compare -Wno-switch -std=gnu++11 -DBOOST_LOG_DYN_LINK")
endif()

find_package(OpenCV REQUIRED core
                             imgproc
                             features2d
                             nonfree
                             highgui
                             )

find_package(Boost REQUIRED COMPONENTS filesystem
                                       program_options
                                       system
                                       thread
                                       locale
                                       regex
                                       date_time
                                       log
                                       log_setup
                                       timer
                                       )

include_directories(src/main/cpp
                    ${Boost_INCLUDE_DIRS}
                    ${OpenCV2_INCLUDE_DIRS}
                    )

add_executable( ${EXECUTABLE_NAME}
                             src/main/cpp/main.cpp
# and the other files
                             )

target_link_libraries(${EXECUTABLE_NAME} ${OpenCV_LIBS}
                                         "-laws-cpp"
                                         "-lcasablanca"
                                         ${Boost_LIBRARIES}
                                         "-lcrypto"
                                         )


find_package(GTest REQUIRED gtest_main
                            pthread)

enable_testing()

include_directories( ${GTEST_INCLUDE_DIRS} )

add_executable(${EXECUTABLE_NAME}_test src/test/cpp/test_Morphology.cpp
                                       src/main/cpp/tools/CMorphology.cpp
                                       src/main/cpp/tools/CMorphology.hpp
                       )

target_link_libraries(${EXECUTABLE_NAME}_test
                                       ${OpenCV_LIBRARIES}
                                       ${Boost_LIBRARIES}
                                       ${GTEST_LIBRARIES}
                                       )

add_test(${EXECUTABLE_NAME}_test
         ${EXECUTABLE_NAME}_test
         )

I have done this a wile ago, and after some commits it is displaying this error. Why does it no longer find that?

Answer 1

Here I provide another case that may possible be a reason for such a link error:

In my project, for some compatibility reason I have to compile my project with a macro "-D_GLIBCXX_USE_CXX11_ABI=0", which forces the compiler to use old C++11 ABI for compilation(in GCC>5.0). However, the gtest library used was compiled before, and was just compiled directly without this option.

And finally i got a similar error but the function signature of testing::internal::EqFailure is like "testing::internal::EqFailure(char const*, char const*, std::__cxx11::string const&, std::__cxx11::string const&, bool)". I don't quite remember the exact signature but there was something like "__cxx11" in the string args rather than std::string. And when I found it I figured out that this may caused by that macro I used.

So this problem was finally solved by recompiling the gtest with "-D_GLIBCXX_USE_CXX11_ABI=0" and then link the new library.

Hope this answer may help for someone.