CMake无法正确链接库

我正在做作业，我的项目树是

.
├── CMakeLists.txt
├── main.c
├── src
│   ├── CMakeLists.txt
│   ├── game
│   │   ├── game.c
│   │   └── game.h
│   └── main.c
└── test
    ├── CMakeLists.txt
    ├── homework_tests
    │   ├── CMakeLists.txt
    │   ├── gtest.cpp
    │   └── gtest.h
    └── lib
        └──googletest
            └──googletest
                └──[library files (not compiled)]

主.c文件中只有一个“Hello，world”。 在阅读之前： 我正在努力：
1.从源文件构建目标

src.so

2.构建google测试库（在

test/lib/

文件夹中）
3.从

tests/

文件夹中构建目标

runBasicTests

4.把它们联系在一起

我承认我不是CMake大师，所以请注意这一点

文件夹 现在，假设我们在项目根

/

： CMakeLists.txt

src/

： CMakeLists.txt game/game.h 家庭作业测试/CMakeLists.txt 家庭作业测试/gtest.cpp 问题是，当我尝试运行测试时，我得到一个链接器错误：

/opt/clion-2018.1/bin/cmake/bin/cmake --build 
/home/denis/CLionProjects/c_homework/cmake-build-debug --target 
runBasicTests -- -j 1

[ 25%] Built target gtest
Scanning dependencies of target src.so
[ 37%] Building C object src/CMakeFiles/src.so.dir/game/game.c.o
[ 50%] Linking C static library libsrc.so.a
[ 50%] **Built target src.so**
[ 75%] Built target gtest_main
[ 87%] Linking CXX executable runBasicTests
CMakeFiles/runBasicTests.dir/gtest.cpp.o: In function 
`gameTests_gameTest1_Test::TestBody()':
/home/denis/CLionProjects/c_homework/test/homework_tests/gtest.cpp:18:

          <---------------   Here   ----------------->   
undefined reference to `is_game_available(game_t, char const*)'
collect2: error: ld returned 1 exit status

test/homework_tests/CMakeFiles/runBasicTests.dir/build.make:98: recipe 
for target 'test/homework_tests/runBasicTests' failed
make[3]: *** [test/homework_tests/runBasicTests] Error 1
CMakeFiles/Makefile2:294: recipe for target 
'test/homework_tests/CMakeFiles/runBasicTests.dir/all' failed
make[2]: *** [test/homework_tests/CMakeFiles/runBasicTests.dir/all] 
Error 2
CMakeFiles/Makefile2:306: recipe for target 
'test/homework_tests/CMakeFiles/runBasicTests.dir/rule' failed
make[1]: *** [test/homework_tests/CMakeFiles/runBasicTests.dir/rule] 
Error 2
Makefile:170: recipe for target 'runBasicTests' failed
make: *** [runBasicTests] Error 2

/opt/clion-2018.1/bin/cmake/bin/cmake--build
/home/denis/CLionProjects/c_作业/cmake构建调试——目标
runBasicTests--j 1
[25%]构建目标gtest
扫描目标src.so的依赖项
[37%]构建C对象src/CMakeFiles/src.so.dir/game/game.C.o
[50%]链接C静态库libsrc.so.a
[50%]**构建目标src.so**
[75%]已建目标gtest_main
[87%]链接CXX可执行runBasicTests
CMakeFiles/runBasicTests.dir/gtest.cpp.o:函数中
`gameTests\u gameTest1\u Test:：TestBody（）'：
/home/denis/CLionProjects/c_家庭作业/测试/家庭作业测试/gtest.cpp:18：
未定义的对“是否有游戏可用（游戏，字符常量*）”的引用
collect2:错误：ld返回了1个退出状态
测试/家庭作业\u测试/CMakeFiles/runBasicTests.dir/build.make:98:recipe
对于目标“测试/家庭作业测试/运行基本测试”失败
生成[3]：***[测试/家庭作业\u测试/运行基本测试]错误1
CMakeFiles/Makefile2:294：目标的配方
“测试/家庭作业\u测试/CMakeFiles/runBasicTests.dir/all”失败
make[2]：***[测试/家庭作业\u测试/CMakeFiles/runBasicTests.dir/all]
错误2
CMakeFiles/Makefile2:306：目标的配方
“测试/家庭作业\u测试/CMakeFiles/runBasicTests.dir/rule”失败
make[1]：***[测试/家庭作业\u测试/CMakeFiles/runBasicTests.dir/rule]
错误2
Makefile:170:目标“runBasicTests”的配方失败
make:**[runBasicTests]错误2

• 不需要我的库的测试可以正常运行
• 位于

  src/

  文件夹中并与

  src链接的目标。因此

  库也会正确运行

---

问题是我从C++代码中调用C代码，C++编译器正在改变函数的名称（名字的变形），这就是为什么我得到和<代码>未定义的引用< /代码>错误。 解决方案是告诉编译器以下函数声明是外部“C”代码
测试/家庭作业\u测试/gtest

---

这就解决了问题。谢谢大家。XD
这可能与以下事实有关：源代码是用

C

编写的，而

C++

中的测试可能不会重复。与这一事实有关。你的<代码>游戏。H//Cuth.Head文件需要找出它是由C或C++编译器编译的（提示：< C++ >

set(SOURCE_FILES
        game/game.c)

add_library(src.so ${SOURCE_FILES})

target_include_directories (src.so PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

#ifndef C_HOMEWORK_GAME_H
#define C_HOMEWORK_GAME_H

#include <stdbool.h>

struct game_t {
    int id, price;
    const char *country_code;
};

bool is_game_available(struct game_t, const char[4]);
int how_many_available(struct game_t*, size_t, const char[4]);

#endif //C_HOMEWORK_GAME_H

#include <string.h>
#include "game.h"

bool is_game_available(struct game_t game, const char country_code[4]) 
{
    return strcmp(game.country_code, country_code) == 0;
}

int how_many_available(struct game_t * games, size_t game_count, const 
char country_code[4]) {
    int available_games = 0;
    for (int i = 0; i < game_count; i++) {
        if (is_game_available(games[i], country_code)) {
            available_games++;
        }
    }
    return available_games;
}

project(homework_tests)

add_subdirectory(lib/googletest/googletest)
add_subdirectory(homework_tests)

include_directories(${gTest_SOURCE_DIR}/include ${gTest_SOURCE_DIR})

add_executable(runBasicTests
        gtest.cpp)

target_link_libraries(runBasicTests gtest gtest_main)
target_link_libraries(runBasicTests src.so)

#include "gtest.h"
#include <game/game.h>

int main(int argc, char **argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

TEST(gameTests, gameTest1) {
    struct game_t game{};
    game.country_code = "359";
    game.id = 1;
    game.price = 69;
    EXPECT_EQ(is_game_available(game, "359"), true);
}

#ifndef MYPROJECTNAME_GTEST_H
#define MYPROJECTNAME_GTEST_H

#include "gtest/gtest.h"

#endif //MYPROJECTNAME_GTEST_H

/opt/clion-2018.1/bin/cmake/bin/cmake --build 
/home/denis/CLionProjects/c_homework/cmake-build-debug --target 
runBasicTests -- -j 1

[ 25%] Built target gtest
Scanning dependencies of target src.so
[ 37%] Building C object src/CMakeFiles/src.so.dir/game/game.c.o
[ 50%] Linking C static library libsrc.so.a
[ 50%] **Built target src.so**
[ 75%] Built target gtest_main
[ 87%] Linking CXX executable runBasicTests
CMakeFiles/runBasicTests.dir/gtest.cpp.o: In function 
`gameTests_gameTest1_Test::TestBody()':
/home/denis/CLionProjects/c_homework/test/homework_tests/gtest.cpp:18:

          <---------------   Here   ----------------->   
undefined reference to `is_game_available(game_t, char const*)'
collect2: error: ld returned 1 exit status

test/homework_tests/CMakeFiles/runBasicTests.dir/build.make:98: recipe 
for target 'test/homework_tests/runBasicTests' failed
make[3]: *** [test/homework_tests/runBasicTests] Error 1
CMakeFiles/Makefile2:294: recipe for target 
'test/homework_tests/CMakeFiles/runBasicTests.dir/all' failed
make[2]: *** [test/homework_tests/CMakeFiles/runBasicTests.dir/all] 
Error 2
CMakeFiles/Makefile2:306: recipe for target 
'test/homework_tests/CMakeFiles/runBasicTests.dir/rule' failed
make[1]: *** [test/homework_tests/CMakeFiles/runBasicTests.dir/rule] 
Error 2
Makefile:170: recipe for target 'runBasicTests' failed
make: *** [runBasicTests] Error 2

#ifdef __cplusplus
extern "C" {
#endif
    /* Declarations of this file */
    bool is_game_available(struct game_t, const char[4]);
    int how_many_available(struct game_t *, size_t, const char[4]);
#ifdef __cplusplus
}
#endif