C++ 对函数 CMake 的未定义引用
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Undefined reference to function CMake
提问by Exagon
I am trying to learn CMake, but I get a undefined reference to ... linker error I have a directory with a subdirectory. each of them has its own CMakeLists.txt
我正在尝试学习 CMake，但我得到了一个未定义的引用...链接器错误 我有一个带有子目录的目录。他们每个人都有自己的 CMakeLists.txt
test
|----main.cpp
|----CMakeLists.txt
|----test2
|----foo.hpp
|----foo.cpp
|----CMakeLists.txt
the CMakeLists.txt for test is:
用于测试的 CMakeLists.txt 是：
cmake_minimum_required(VERSION 3.5)
project(tests)
add_subdirectory(test2)
set(SOURCE_FILES main.cpp)
add_executable(tests ${SOURCE_FILES})
the CMakeLists.txt for test2 is:
test2 的 CMakeLists.txt 是：
set(test2_files
foo.cpp
foo.hpp
)
add_library(test2 ${test2_files})
foo.cppimplements a function which is defined in foo.hppfor this function I am getting the undefined reference error.
What am I doing wrong? How can I get rid of this linker error
foo.cpp实现了一个foo.hpp为此函数定义的函数，我收到未定义的引用错误。我究竟做错了什么？我怎样才能摆脱这个链接器错误
EDIT: My CMakeLists.txt now looks like this, but I still get the linker error:
编辑：我的 CMakeLists.txt 现在看起来像这样，但我仍然收到链接器错误：
project(tests)
cmake_minimum_required(VERSION 2.8)
set(SOURCE_FILES main.cpp)
include_directories(test2)
link_directories(test2)
add_subdirectory(test)
add_executable( ${PROJECT_NAME} ${SOURCE_FILES} )
target_link_libraries(${PROJECT_NAME} test2)
I also tried it with the absolute path instead of test2
我也用绝对路径而不是 test2
EDIT: solved it it was only a typo in the CMakeLists.txt of test2.
编辑：解决了它只是 test2 的 CMakeLists.txt 中的一个错字。
回答by davepmiller
Make sure that your test CMakeLists.txtlinks to the created library.
确保您的测试CMakeLists.txt链接到创建的库。
project(test)
cmake_minimum_required(VERSION 2.8)
set(SOURCE_FILES main.cpp)
include_directories( test2 )
#here
link_directories(test2)
add_subdirectory(test2)
add_executable( ${PROJECT_NAME} ${SOURCE_FILES} )
#and here
target_link_libraries( ${PROJECT_NAME} test2 )
回答by kivi
Function add_subdirectory($dir)does not automatically add $dirto include directories and link directories. To use library test2you should do it manually in CMakeLists.txt of testdirectory:
函数add_subdirectory($dir)不会自动添加$dir包含目录和链接目录。要使用库，test2您应该在test目录的CMakeLists.txt 中手动执行：
include_directories(test2/)
link_directories(test2/)
Then, link your executable with test2library to get functions definitions. Add to CMakeLists.txt of testdirectory:
然后，将您的可执行文件与test2库链接以获取函数定义。添加到test目录的CMakeLists.txt 中：
target_link_libraries(tests test2)
