尽管在 CMake 中指定了库，但仍存在未定义的引用错误（与 libtorch 链接的问题（C++11 ABI？）
Undefined reference error despite of having the library specified in CMake (issues linking with libtorch (C++11 ABI?)
我正在尝试从我制作的库中创建一个测试可执行文件。我们将它们命名为 lib1 和 lib2。 lib1 与其测试一起构建得很好。 lib2 的构建也没有任何问题。但是，每当我尝试 link lib2 及其测试可执行文件（即使用 lib2 的示例程序）时，我都会收到以下错误：
usr/bin/ld: CMakeFiles/Lib2_Test.dir/Lib2_Test.cpp.o: in function `main':
Lib2_Test.cpp:(.text+0xf3): undefined reference to `Lib2::Lib2(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, int)'
/usr/bin/ld: Lib2_Test.cpp:(.text+0x3f5): undefined reference to `Lib2::Evaluate(bool&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, float&, cv::Mat&, cv::Mat&, bool)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/Lib2_Test.dir/build.make:130: Lib2_Test] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/Lib2_Test.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
我尝试使用 readelf -d 和 ldd 命令查看 headers，这两个库似乎都有所有必要的引用。但是 lib1 没有任何问题，而 lib2 在被 linked 到使用它的可执行文件时会生成未引用的相关错误。
下面是我为它们制作的 cmakeLists，后来我还包括了 readelf.
的输出
CMakelist.txt 对于 lib1:
cmake_minimum_required(VERSION 3.11)
project(Lib1)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
add_definitions(-D_LIB1_BUILD_DLL)
set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC" )
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib)
# http://dlib.net/examples/CMakeLists.txt.html
add_subdirectory(/home/me/dlib-19.21 /home/me/dlib-19.21/build)
set(Lib1_SRC ./lib1.cpp)
add_library(lib1 SHARED ${Lib1_SRC})
# Link
target_link_libraries(lib1 ${TORCH_LIBRARIES})
target_link_libraries(lib1 ${OpenCV_LIBS})
target_link_libraries(lib1 dlib::dlib)
install(TARGETS lib1 LIBRARY DESTINATION lib)
这是 lib1_test 的 CMakeList.txt:
cmake_minimum_required(VERSION 3.11)
project(Lib1_Test)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
# Link
add_executable(lib1_dynamic_test ./Lib1_Test.cpp)
target_link_directories(lib1_dynamic_test PRIVATE /home/me/Desktop/LibtorchPort/Lib1/build)
target_link_libraries(lib1_dynamic_test lib1 )
target_link_libraries(lib1_dynamic_test ${TORCH_LIBRARIES} )
target_link_libraries(lib1_dynamic_test ${OpenCV_LIBS})
install(TARGETS lib1_dynamic_test DESTINATION bin)
这是 lib2 的 CMakeList.txt:
cmake_minimum_required(VERSION 3.11)
project(Lib2)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
add_definitions(-D_LIB2_BUILD_DLL)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib)
LINK_DIRECTORIES(/home/me/Desktop/LibtorchPort/Lib1/build)
set(LIB2_SRC ./lib2.cpp )
add_library(lib2_dynamic SHARED ${LIB2_SRC} )
target_link_directories(lib2_dynamic PRIVATE /home/me/Desktop/LibtorchPort/Lib1/build)
target_link_libraries(lib2_dynamic lib1)
target_link_libraries(lib2_dynamic ${TORCH_LIBRARIES})
target_link_libraries(lib2_dynamic ${OpenCV_LIBS})
install(TARGETS lib2_dynamic LIBRARY DESTINATION lib)
最后是 lib2_test:
的 CMakeList
cmake_minimum_required(VERSION 3.11)
project(Lib2_Test)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
#find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/Desktop/LibtorchPort/Lib1/build)
add_executable(Lib2_Test ./lib2_test.cpp)
target_link_directories(Lib2_Test PRIVATE /home/me/Desktop/LibtorchPort/Lib2/build)
#target_link_directories(Lib2_Test PUBLIC /home/me/Desktop/LibtorchPort/Lib1/build)
#Link
target_link_libraries(Lib2_Test ${OpenCV_LIBS})
target_link_libraries(Lib2_Test lib2_dynamic)
install(TARGETS Lib2_Test DESTINATION bin)
运行 readelf -d lib1 这是我得到的输出：
Dynamic section at offset 0x908f8 contains 38 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libtorch.so]
0x0000000000000001 (NEEDED) Shared library: [libc10.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch_cpu.so]
0x0000000000000001 (NEEDED) Shared library: [libopencv_highgui.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libopencv_imgproc.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libcblas.so.3]
0x0000000000000001 (NEEDED) Shared library: [liblapack.so.3]
0x0000000000000001 (NEEDED) Shared library: [libstdc++.so.6]
0x0000000000000001 (NEEDED) Shared library: [libm.so.6]
0x0000000000000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x0000000000000001 (NEEDED) Shared library: [ld-linux-x86-64.so.2]
0x000000000000000e (SONAME) Library soname: [libLib1.so]
0x000000000000001d (RUNPATH) Library runpath: [/home/me/anaconda3/lib/python3.8/site-packages/torch/lib:/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib:/usr/local/lib:]
0x000000000000000c (INIT) 0x1a000
0x000000000000000d (FINI) 0x57e00
0x0000000000000019 (INIT_ARRAY) 0x90b28
0x000000000000001b (INIT_ARRAYSZ) 32 (bytes)
0x000000000000001a (FINI_ARRAY) 0x90b48
0x000000000000001c (FINI_ARRAYSZ) 8 (bytes)
0x000000006ffffef5 (GNU_HASH) 0x328
0x0000000000000005 (STRTAB) 0x6840
0x0000000000000006 (SYMTAB) 0x1758
0x000000000000000a (STRSZ) 56053 (bytes)
0x000000000000000b (SYMENT) 24 (bytes)
0x0000000000000003 (PLTGOT) 0x92000
0x0000000000000002 (PLTRELSZ) 8112 (bytes)
0x0000000000000014 (PLTREL) RELA
0x0000000000000017 (JMPREL) 0x17ff0
0x0000000000000007 (RELA) 0x14b58
0x0000000000000008 (RELASZ) 13464 (bytes)
0x0000000000000009 (RELAENT) 24 (bytes)
0x000000006ffffffe (VERNEED) 0x149f8
0x000000006fffffff (VERNEEDNUM) 5
0x000000006ffffff0 (VERSYM) 0x14336
0x000000006ffffff9 (RELACOUNT) 6
0x0000000000000000 (NULL) 0x0
这是 lib2 的输出：
Dynamic section at offset 0x37ba0 contains 32 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libLib1.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch_cpu.so]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libstdc++.so.6]
0x0000000000000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x000000000000000e (SONAME) Library soname: [libLib2_dynamic.so]
0x000000000000001d (RUNPATH) Library runpath: [/home/me/anaconda3/lib/python3.8/site-packages/torch/lib:/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib:/home/me/Desktop/LibtorchPort/Lib1/build:/usr/local/lib:]
0x000000000000000c (INIT) 0x1e000
0x000000000000000d (FINI) 0x2ec10
0x0000000000000019 (INIT_ARRAY) 0x38108
0x000000000000001b (INIT_ARRAYSZ) 16 (bytes)
0x000000000000001a (FINI_ARRAY) 0x38118
0x000000000000001c (FINI_ARRAYSZ) 8 (bytes)
0x000000006ffffef5 (GNU_HASH) 0x2f0
0x0000000000000005 (STRTAB) 0x7d88
0x0000000000000006 (SYMTAB) 0x1dd0
0x000000000000000a (STRSZ) 62708 (bytes)
0x000000000000000b (SYMENT) 24 (bytes)
0x0000000000000003 (PLTGOT) 0x39000
0x0000000000000002 (PLTRELSZ) 14784 (bytes)
0x0000000000000014 (PLTREL) RELA
0x0000000000000017 (JMPREL) 0x19e90
0x0000000000000007 (RELA) 0x17b38
0x0000000000000008 (RELASZ) 9048 (bytes)
0x0000000000000009 (RELAENT) 24 (bytes)
0x000000006ffffffe (VERNEED) 0x17a78
0x000000006fffffff (VERNEEDNUM) 3
0x000000006ffffff0 (VERSYM) 0x1727c
0x000000006ffffff9 (RELACOUNT) 4
0x0000000000000000 (NULL) 0x0
然而 lib1 构建和 link 都很好，而 lib2 依赖于 lib1，在 linked 时有问题对其测试或任何其他库。在这一点上我一无所知，不知道是什么原因造成的。我错过了什么？
更新 1
这是 lib2_test.cpp : https://paste.ee/p/pOgFk
这就是 header 文件的样子：
#ifndef Lib2_H
#define Lib2_H
/* If we are we on Windows, we want a single define for it.*/
#if !defined(_WIN32) && (defined(__WIN32__) || defined(WIN32) || defined(__MINGW32__))
#define _WIN32
#endif /* _WIN32 */
#if defined(_WIN32) && defined(_Lib2_BUILD_DLL)
/* We are building Lib2 as a Win32 DLL */
#define LIB2_API __declspec(dllexport)
#elif defined(_WIN32) && defined(Lib2_DLL)
/* We are calling Lib2 as a Win32 DLL */
#define LIB2_API __declspec(dllimport)
#elif defined(__GNUC__) && defined(_Lib2_BUILD_DLL)
/* We are building Lib2 as a shared / dynamic library */
#define LIB2_API __attribute__((visibility("default")))
#else
/* We are building or calling Lib2 as a static library */
#define LIB2_API
#endif
#include <string>
#include <vector>
#include <map>
#include <memory>
#include <opencv2/core.hpp>
enum class ValidationStatus
{
None = -1,
UnderValidation = 0,
Validated = 1,
Invalidated = 2,
AnomalyDetected = 3,
ToomuchAnonalyDetected = 4
};
typedef std::tuple<ValidationStatus, std::string, bool> Lib2Result;
class Lib2Impl;
class LIB2_API Lib2
{
private:
std::shared_ptr<Lib2Impl> Lib2;
public:
Lib2(std::string shape_predictor_path = "", std::string eyeNet_path = "", int valid_presence_delay = 5, int fpasPassed = 0);
std::vector<Lib2Result> Run(std::map<std::string, bool>& validity_result,
std::vector<std::tuple<std::string, float>>& ids,
std::vector<cv::Mat>& faces,
cv::Mat& originalImage,
bool show_debug_info=false);
Lib2Result Evaluate(bool& status, std::string& name, float& theta, cv::Mat& face_image, cv::Mat& originalImage, bool debug_info = true);
~Lib2();
};
#endif // !Lib2_H
关于评论，如您所见，lib2_test.cpp 上的调用正常并且使用相同的签名。
更新 2
我还需要补充一点，该项目是在 Windows 中使用 Visual Studio 和 cmake 构建的！然而，在
Linux (Ubuntu 20.04)，我正面临这些问题。所以这不仅仅是调用 different/wrong 方法或使用错误的签名。这段代码应该可以编译并且 link 很好，但是我在这里做错了，我不确定它是什么。
注2
lib1 和 lib2 只是实际文件名的名称（我只是选择 lib1 和 lib2 以简化事情并替换了此处的名称，所以如果您发现大小写不同，请不要介意，实际文件相同。
总结
第三方库（torch）是使用 Pre-cxx11 ABI 构建的，用它构建的库显然不能链接到使用 cxx11 ABI 的对象！
详细解释
经过数小时的代码调试，该代码在 Windows 和 Visual Studio 中都运行良好，而在 Linux 中却令人头疼，我找到了罪魁祸首！
libtorch 附带两种类型的构建 Pre-cxx11 和 cxx11 ABI！
它使用 Python 包 (torch1.6cpu) 附带的 Pre-cxx11 内置库，因为 Anaconda3 在路径中，我也使用它来构建我遇到这个问题的库。
在所有这些时间之后泄露的是对未定义方法的奇怪论点，这些论点是：std::__cxx11::basic_string 本来应该是 std::string。我没想到这两个会有所不同，我想，这是 g++ 直到刚才才使用的一个奇怪的命名方案，这让我说，让我们搜索一下，也许我能找到一些东西！瞧！是这样的：
If you get linker errors about undefined references to symbols that
involve types in the std::__cxx11 namespace or the tag [abi:cxx11]
then it probably indicates that you are trying to link together object
files that were compiled with different values for the
_GLIBCXX_USE_CXX11_ABI macro. This commonly happens when linking to a third-party library that was compiled with an older version of GCC. If
the third-party library cannot be rebuilt with the new ABI then you
will need to recompile your code with the old ABI.
为了解决这个问题，我只是在所有库创建中直接使用了 libtorch cxx11 并且就这样完成了。这意味着，与 Pytorch 官方文档中显示的内容不同。不要做：
cmake -DCMAKE_PREFIX_PATH="$(python -c 'import torch.utils; print(torch.utils.cmake_prefix_path)')" ..
通过这样做，如果你像我一样期望库是用 cxx11 构建的，那么一切都会变得一团糟！因为他们没有！
因此，如果您使用 Linux，只需获取并使用带有 CXX11 ABI 的预构建库！并避免 Pytorch 附带的东西！
备注
如果您正在使用 Pybind11 和 libtorch 构建 Python 扩展，请确保您的 Pytorch 也是使用 GLIBCXX_USE_CXX11_ABI=1 构建的，否则您将看到未定义的引用，原因您现在知道了！您可以通过 运行 terminal/cmd 中的以下代码片段简单地进行检查：
python -c "import torch; print(f'GLIBCXX_USE_CXX11_ABI = {int(torch._C._GLIBCXX_USE_CXX11_ABI)}')"
基于 information provided here conda 包（仅限 cuda 构建）应随 GLIBCXX_USE_CXX11_ABI=1 一起提供。我使用 pip 和 conda 测试了 1.6cpu，但它们都报告了 GLIBCXX_USE_CXX11_ABI = 0。所以要注意这一点。
如果您恰好需要从源码构建，可以关注this guide.
至于为什么 Pytorch 是这样发布的：
we have that flag set because we build with gcc 4.9.x, which only has
the old ABI. In GCC 5.1, the ABI for std::string was changed, and
binaries compiling with gcc >= 5.1 are not ABI-compatible with
binaries build with gcc < 5.1 (like pytorch) unless you set that flag.
ref
我正在尝试从我制作的库中创建一个测试可执行文件。我们将它们命名为 lib1 和 lib2。 lib1 与其测试一起构建得很好。 lib2 的构建也没有任何问题。但是，每当我尝试 link lib2 及其测试可执行文件（即使用 lib2 的示例程序）时，我都会收到以下错误：
usr/bin/ld: CMakeFiles/Lib2_Test.dir/Lib2_Test.cpp.o: in function `main':
Lib2_Test.cpp:(.text+0xf3): undefined reference to `Lib2::Lib2(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, int)'
/usr/bin/ld: Lib2_Test.cpp:(.text+0x3f5): undefined reference to `Lib2::Evaluate(bool&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, float&, cv::Mat&, cv::Mat&, bool)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/Lib2_Test.dir/build.make:130: Lib2_Test] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/Lib2_Test.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
我尝试使用 readelf -d 和 ldd 命令查看 headers，这两个库似乎都有所有必要的引用。但是 lib1 没有任何问题，而 lib2 在被 linked 到使用它的可执行文件时会生成未引用的相关错误。
下面是我为它们制作的 cmakeLists，后来我还包括了 readelf.
CMakelist.txt 对于 lib1:
cmake_minimum_required(VERSION 3.11)
project(Lib1)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
add_definitions(-D_LIB1_BUILD_DLL)
set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC" )
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib)
# http://dlib.net/examples/CMakeLists.txt.html
add_subdirectory(/home/me/dlib-19.21 /home/me/dlib-19.21/build)
set(Lib1_SRC ./lib1.cpp)
add_library(lib1 SHARED ${Lib1_SRC})
# Link
target_link_libraries(lib1 ${TORCH_LIBRARIES})
target_link_libraries(lib1 ${OpenCV_LIBS})
target_link_libraries(lib1 dlib::dlib)
install(TARGETS lib1 LIBRARY DESTINATION lib)
这是 lib1_test 的 CMakeList.txt:
cmake_minimum_required(VERSION 3.11)
project(Lib1_Test)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
# Link
add_executable(lib1_dynamic_test ./Lib1_Test.cpp)
target_link_directories(lib1_dynamic_test PRIVATE /home/me/Desktop/LibtorchPort/Lib1/build)
target_link_libraries(lib1_dynamic_test lib1 )
target_link_libraries(lib1_dynamic_test ${TORCH_LIBRARIES} )
target_link_libraries(lib1_dynamic_test ${OpenCV_LIBS})
install(TARGETS lib1_dynamic_test DESTINATION bin)
这是 lib2 的 CMakeList.txt:
cmake_minimum_required(VERSION 3.11)
project(Lib2)
set(CMAKE_CXX_STANDARD 17)
find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
add_definitions(-D_LIB2_BUILD_DLL)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${TORCH_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib)
LINK_DIRECTORIES(/home/me/Desktop/LibtorchPort/Lib1/build)
set(LIB2_SRC ./lib2.cpp )
add_library(lib2_dynamic SHARED ${LIB2_SRC} )
target_link_directories(lib2_dynamic PRIVATE /home/me/Desktop/LibtorchPort/Lib1/build)
target_link_libraries(lib2_dynamic lib1)
target_link_libraries(lib2_dynamic ${TORCH_LIBRARIES})
target_link_libraries(lib2_dynamic ${OpenCV_LIBS})
install(TARGETS lib2_dynamic LIBRARY DESTINATION lib)
最后是 lib2_test:
cmake_minimum_required(VERSION 3.11)
project(Lib2_Test)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_INSTALL_PREFIX /home/me/Desktop/LibtorchPort/built_stuff)
#find_package(Torch REQUIRED)
find_package(OpenCV REQUIRED)
include_directories( /home/me/Desktop/LibtorchPort/Dependencies/include ${OpenCV_INCLUDE_DIRS})
LINK_DIRECTORIES(/home/me/Desktop/LibtorchPort/Lib1/build)
add_executable(Lib2_Test ./lib2_test.cpp)
target_link_directories(Lib2_Test PRIVATE /home/me/Desktop/LibtorchPort/Lib2/build)
#target_link_directories(Lib2_Test PUBLIC /home/me/Desktop/LibtorchPort/Lib1/build)
#Link
target_link_libraries(Lib2_Test ${OpenCV_LIBS})
target_link_libraries(Lib2_Test lib2_dynamic)
install(TARGETS Lib2_Test DESTINATION bin)
运行 readelf -d lib1 这是我得到的输出：
Dynamic section at offset 0x908f8 contains 38 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libtorch.so]
0x0000000000000001 (NEEDED) Shared library: [libc10.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch_cpu.so]
0x0000000000000001 (NEEDED) Shared library: [libopencv_highgui.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libopencv_imgproc.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libcblas.so.3]
0x0000000000000001 (NEEDED) Shared library: [liblapack.so.3]
0x0000000000000001 (NEEDED) Shared library: [libstdc++.so.6]
0x0000000000000001 (NEEDED) Shared library: [libm.so.6]
0x0000000000000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x0000000000000001 (NEEDED) Shared library: [ld-linux-x86-64.so.2]
0x000000000000000e (SONAME) Library soname: [libLib1.so]
0x000000000000001d (RUNPATH) Library runpath: [/home/me/anaconda3/lib/python3.8/site-packages/torch/lib:/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib:/usr/local/lib:]
0x000000000000000c (INIT) 0x1a000
0x000000000000000d (FINI) 0x57e00
0x0000000000000019 (INIT_ARRAY) 0x90b28
0x000000000000001b (INIT_ARRAYSZ) 32 (bytes)
0x000000000000001a (FINI_ARRAY) 0x90b48
0x000000000000001c (FINI_ARRAYSZ) 8 (bytes)
0x000000006ffffef5 (GNU_HASH) 0x328
0x0000000000000005 (STRTAB) 0x6840
0x0000000000000006 (SYMTAB) 0x1758
0x000000000000000a (STRSZ) 56053 (bytes)
0x000000000000000b (SYMENT) 24 (bytes)
0x0000000000000003 (PLTGOT) 0x92000
0x0000000000000002 (PLTRELSZ) 8112 (bytes)
0x0000000000000014 (PLTREL) RELA
0x0000000000000017 (JMPREL) 0x17ff0
0x0000000000000007 (RELA) 0x14b58
0x0000000000000008 (RELASZ) 13464 (bytes)
0x0000000000000009 (RELAENT) 24 (bytes)
0x000000006ffffffe (VERNEED) 0x149f8
0x000000006fffffff (VERNEEDNUM) 5
0x000000006ffffff0 (VERSYM) 0x14336
0x000000006ffffff9 (RELACOUNT) 6
0x0000000000000000 (NULL) 0x0
这是 lib2 的输出：
Dynamic section at offset 0x37ba0 contains 32 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libLib1.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch.so]
0x0000000000000001 (NEEDED) Shared library: [libtorch_cpu.so]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.3.4]
0x0000000000000001 (NEEDED) Shared library: [libstdc++.so.6]
0x0000000000000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x000000000000000e (SONAME) Library soname: [libLib2_dynamic.so]
0x000000000000001d (RUNPATH) Library runpath: [/home/me/anaconda3/lib/python3.8/site-packages/torch/lib:/home/me/libtorch-cxx11-abi-shared-with-deps-1.6.0+cpu/libtorch/lib:/home/me/Desktop/LibtorchPort/Lib1/build:/usr/local/lib:]
0x000000000000000c (INIT) 0x1e000
0x000000000000000d (FINI) 0x2ec10
0x0000000000000019 (INIT_ARRAY) 0x38108
0x000000000000001b (INIT_ARRAYSZ) 16 (bytes)
0x000000000000001a (FINI_ARRAY) 0x38118
0x000000000000001c (FINI_ARRAYSZ) 8 (bytes)
0x000000006ffffef5 (GNU_HASH) 0x2f0
0x0000000000000005 (STRTAB) 0x7d88
0x0000000000000006 (SYMTAB) 0x1dd0
0x000000000000000a (STRSZ) 62708 (bytes)
0x000000000000000b (SYMENT) 24 (bytes)
0x0000000000000003 (PLTGOT) 0x39000
0x0000000000000002 (PLTRELSZ) 14784 (bytes)
0x0000000000000014 (PLTREL) RELA
0x0000000000000017 (JMPREL) 0x19e90
0x0000000000000007 (RELA) 0x17b38
0x0000000000000008 (RELASZ) 9048 (bytes)
0x0000000000000009 (RELAENT) 24 (bytes)
0x000000006ffffffe (VERNEED) 0x17a78
0x000000006fffffff (VERNEEDNUM) 3
0x000000006ffffff0 (VERSYM) 0x1727c
0x000000006ffffff9 (RELACOUNT) 4
0x0000000000000000 (NULL) 0x0
然而 lib1 构建和 link 都很好，而 lib2 依赖于 lib1，在 linked 时有问题对其测试或任何其他库。在这一点上我一无所知，不知道是什么原因造成的。我错过了什么？
更新 1
这是 lib2_test.cpp : https://paste.ee/p/pOgFk
这就是 header 文件的样子：
#ifndef Lib2_H
#define Lib2_H
/* If we are we on Windows, we want a single define for it.*/
#if !defined(_WIN32) && (defined(__WIN32__) || defined(WIN32) || defined(__MINGW32__))
#define _WIN32
#endif /* _WIN32 */
#if defined(_WIN32) && defined(_Lib2_BUILD_DLL)
/* We are building Lib2 as a Win32 DLL */
#define LIB2_API __declspec(dllexport)
#elif defined(_WIN32) && defined(Lib2_DLL)
/* We are calling Lib2 as a Win32 DLL */
#define LIB2_API __declspec(dllimport)
#elif defined(__GNUC__) && defined(_Lib2_BUILD_DLL)
/* We are building Lib2 as a shared / dynamic library */
#define LIB2_API __attribute__((visibility("default")))
#else
/* We are building or calling Lib2 as a static library */
#define LIB2_API
#endif
#include <string>
#include <vector>
#include <map>
#include <memory>
#include <opencv2/core.hpp>
enum class ValidationStatus
{
None = -1,
UnderValidation = 0,
Validated = 1,
Invalidated = 2,
AnomalyDetected = 3,
ToomuchAnonalyDetected = 4
};
typedef std::tuple<ValidationStatus, std::string, bool> Lib2Result;
class Lib2Impl;
class LIB2_API Lib2
{
private:
std::shared_ptr<Lib2Impl> Lib2;
public:
Lib2(std::string shape_predictor_path = "", std::string eyeNet_path = "", int valid_presence_delay = 5, int fpasPassed = 0);
std::vector<Lib2Result> Run(std::map<std::string, bool>& validity_result,
std::vector<std::tuple<std::string, float>>& ids,
std::vector<cv::Mat>& faces,
cv::Mat& originalImage,
bool show_debug_info=false);
Lib2Result Evaluate(bool& status, std::string& name, float& theta, cv::Mat& face_image, cv::Mat& originalImage, bool debug_info = true);
~Lib2();
};
#endif // !Lib2_H
关于评论，如您所见，lib2_test.cpp 上的调用正常并且使用相同的签名。
更新 2
我还需要补充一点，该项目是在 Windows 中使用 Visual Studio 和 cmake 构建的！然而，在 Linux (Ubuntu 20.04)，我正面临这些问题。所以这不仅仅是调用 different/wrong 方法或使用错误的签名。这段代码应该可以编译并且 link 很好，但是我在这里做错了，我不确定它是什么。
注2
lib1 和 lib2 只是实际文件名的名称（我只是选择 lib1 和 lib2 以简化事情并替换了此处的名称，所以如果您发现大小写不同，请不要介意，实际文件相同。
总结
第三方库（torch）是使用 Pre-cxx11 ABI 构建的，用它构建的库显然不能链接到使用 cxx11 ABI 的对象！
详细解释
经过数小时的代码调试，该代码在 Windows 和 Visual Studio 中都运行良好，而在 Linux 中却令人头疼，我找到了罪魁祸首！
libtorch 附带两种类型的构建 Pre-cxx11 和 cxx11 ABI！
它使用 Python 包 (torch1.6cpu) 附带的 Pre-cxx11 内置库，因为 Anaconda3 在路径中，我也使用它来构建我遇到这个问题的库。
在所有这些时间之后泄露的是对未定义方法的奇怪论点，这些论点是：std::__cxx11::basic_string 本来应该是 std::string。我没想到这两个会有所不同，我想，这是 g++ 直到刚才才使用的一个奇怪的命名方案，这让我说，让我们搜索一下，也许我能找到一些东西！瞧！是这样的：
If you get linker errors about undefined references to symbols that involve types in the std::__cxx11 namespace or the tag [abi:cxx11] then it probably indicates that you are trying to link together object files that were compiled with different values for the _GLIBCXX_USE_CXX11_ABI macro. This commonly happens when linking to a third-party library that was compiled with an older version of GCC. If the third-party library cannot be rebuilt with the new ABI then you will need to recompile your code with the old ABI.
为了解决这个问题，我只是在所有库创建中直接使用了 libtorch cxx11 并且就这样完成了。这意味着，与 Pytorch 官方文档中显示的内容不同。不要做：
cmake -DCMAKE_PREFIX_PATH="$(python -c 'import torch.utils; print(torch.utils.cmake_prefix_path)')" ..
通过这样做，如果你像我一样期望库是用 cxx11 构建的，那么一切都会变得一团糟！因为他们没有！
因此，如果您使用 Linux，只需获取并使用带有 CXX11 ABI 的预构建库！并避免 Pytorch 附带的东西！
备注
如果您正在使用 Pybind11 和 libtorch 构建 Python 扩展，请确保您的 Pytorch 也是使用 GLIBCXX_USE_CXX11_ABI=1 构建的，否则您将看到未定义的引用，原因您现在知道了！您可以通过 运行 terminal/cmd 中的以下代码片段简单地进行检查：
python -c "import torch; print(f'GLIBCXX_USE_CXX11_ABI = {int(torch._C._GLIBCXX_USE_CXX11_ABI)}')"
基于 information provided here conda 包（仅限 cuda 构建）应随 GLIBCXX_USE_CXX11_ABI=1 一起提供。我使用 pip 和 conda 测试了 1.6cpu，但它们都报告了 GLIBCXX_USE_CXX11_ABI = 0。所以要注意这一点。
如果您恰好需要从源码构建，可以关注this guide.
至于为什么 Pytorch 是这样发布的：
we have that flag set because we build with gcc 4.9.x, which only has the old ABI. In GCC 5.1, the ABI for std::string was changed, and binaries compiling with gcc >= 5.1 are not ABI-compatible with binaries build with gcc < 5.1 (like pytorch) unless you set that flag. ref