gtest installed with conan: undefined reference to

问题:

I use cmake to build my project and conan to install Google Test as dependency:

conanfile.txt

[requires]
gtest/1.7.0@lasote/stable

[generators]
cmake

[imports]
bin, *.dll -> ./build/bin
lib, *.dylib* -> ./build/bin

CMakeLists.txt

PROJECT(MyTestingExample)
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)

INCLUDE(conanbuildinfo.cmake)
CONAN_BASIC_SETUP()

ADD_EXECUTABLE(my_test test/my_test.cpp)
TARGET_LINK_LIBRARIES(my_test ${CONAN_LIBS})

test/my_test.cpp

#include <gtest/gtest.h>
#include <string>

TEST(MyTest, foobar) {
    std::string foo("foobar");
    std::string bar("foobar");
    ASSERT_STREQ(foo.c_str(), bar.c_str()); // working
    EXPECT_FALSE(false); // error
}

Build

$ conan install --build=missing
$ mkdir build && cd build
$ cmake .. && cmake --build .

I can use ASSERT_STREQ, but if I use EXPECT_FALSE I get an unexpected error:

my_test.cpp:(.text+0x1e1): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
collect2: error: ld returned 1 exit status

What's wrong with my configuration?

回答1:

The issue is that you are installing conan dependencies using the default settings (which is build type Release):

$ conan install --build=missing
# equivalent to
$ conan install -s build_type=Release ... --build=missing

The default settings can be seen in your conan.conf file

Then, you are using cmake in a nix system with the default build type which is Debug, which is a single-conf environment (opposed to multi-configuration Debug/Release environments, as Visual Studio), so when you are doing:

$ cmake .. && cmake --build .
# equivalent to
$ cmake .. -DCMAKE_BUILD_TYPE=Debug && cmake --build .

The incompatibility of Debug/Release build leads to that unresolved issue. So the solution would be to use the same build type that matches your installed dependencies:

$ cmake .. -DCMAKE_BUILD_TYPE=Release && cmake --build .

If using multi-configuration environments like Visual Studio, the correct way would be:

$ cmake .. && cmake --build . --config Release