获取链接器错误LNK2001：使用Pybind11

问题描述

我正在尝试使用Pybind11构建Python扩展，并且我相信我正确设置了所有库，链接器相关对象。但是我得到这个奇怪的链接器错误！ 这是我的示例输入

#include <string>
#include <vector>

#include <torch/script.h>
#include <pybind11/pybind11.h>
namespace py = pybind11;

#include <FV/FV.h>
//template <class T>
class PyManager 
{
public:
    PyManager(std::string model_path,std::string img_bank_folder_root,std::string cache_folder,std::string pnet,std::string rnet,std::string onet,bool rebuildCache)
    {
        auto config = FV::Load_Default_Settings();
        //...
        fv = std::make_shared<FV>(config);
    }


    int AddUser(std::string user_id,std::string img_fldr_path)
    {
        return fv->AddNewUser(user_id,img_fldr_path);
    }
    int RemoveUser(std::string user_id)
    {
        return fv->RemoveUser(user_id);
    }
    int UpdateUser(std::string user_id,std::string new_images_folder_path)
    {
        return fv->UpdateUser(user_id,new_images_folder_path);
    }
    int UpdateUsersInBulk(std::vector<std::string> userIDs,std::string ID_folders_path,bool is_delete_granted = true,bool show_dbg_info = true)
    {
        return fv->UpdateUsersInBulk(userIDs,ID_folders_path,is_delete_granted,show_dbg_info);

    }
    int RenameId(std::string old_id,std::string new_id)
    {
       return fv->RenameUserID(old_id,new_id);
    }

private:
    std::shared_ptr<FV> fv;
};

PYBIND11_MODULE(PythonUserManager,m) {
    py::class_<PyManager>(m,"Manager")
        .def(py::init<std::string,std::string,bool>())
        .def("add",&PyManager::AddUser)
        .def("remove",&PyManager::RemoveUser)
        .def("update",&PyManager::UpdateUser)
        .def("rename",&PyManager::RenameId)
        .def("update_in_bulk",&PyManager::UpdateUsersInBulk);
}

这就是我构建扩展名（setup.py）的方式：

import os,sys
from os import environ,getcwd
from distutils.core import setup,Extension
from distutils import sysconfig
import getpass 
cpp_args = ['/std:c++17']

user = getpass.getuser()
sfc_module = Extension(
    'pythonmanager_Pybind11',sources=['pythonmanager_Pybind11.cpp','D:/cpp/port/LibtorchPort/Dependencies/include/messages/Config.pb.cc'],include_dirs=['pybind11/include',f'C:/Users/{user}/Anaconda3/include',f'C:/Users/{user}/Anaconda3/include/pybind11/',"D:/External Libs/Opencv3.4.10_vc14_vc15/opencv3.4/include","D:/cpp/port/LibtorchPort/Dependencies/include","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/include","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/include/torch/csrc/api/include",f'C:/Users/{user}/Anaconda3/Library/include',f'C:/Users/{user}/Anaconda3/Lib/site-packages/numpy/core/include'],library_dirs=[# python3.6.7: f'C:/Users/{user}/Anaconda3/pkgs/openblas-0.3.3-h535eed3_1001/Library/lib',"D:/cpp/port/LibtorchPort/x64/Release","D:/External Libs/Opencv3.4.10_vc14_vc15/opencv3.4/x64/vc14/lib","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/lib",f'C:/Users/{user}/Anaconda3/libs',f'C:/Users/{user}/Anaconda3'],libraries=['FV','libprotobuf-lite','libprotobuf','libprotoc','c10','asmjit','clog','cpuinfo','dnnl','fbgemm','mkldnn','torch','torch_cpu'],language='c++',extra_compile_args=cpp_args,)

setup(
    name='UserManager',version='1.0',description='Python package with PythonExtension C++ extension (PyBind11)',ext_modules=[sfc_module],)

导致以下链接器错误：

    creating C:\Users\User\AppData\Local\Temp\pip-req-build-xl1k7s1f\build\lib.win-amd64-3.7
    C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\bin\HostX86\x64\link.exe /nologo /INCREMENTAL:NO /LTCG /DLL /MANIFEST:EMbed,ID=2 /MANIFESTUAC:NO /LIBPATH:D:/Codes/fac_ver/cpp/port/LibtorchPort/x64/Release "/LIBPATH:D:/External Libs/Opencv3.4.10_vc14_vc15/opencv3.4/x64/vc14/lib" /LIBPATH:D:/Codes/fac_ver/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/lib /LIBPATH:C:/Users/User/Anaconda3/libs /LIBPATH:C:/Users/User/Anaconda3 /LIBPATH:C:\Users\User\Anaconda3\libs /LIBPATH:C:\Users\User\Anaconda3\PCbuild\amd64 "/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\ATLMFC\lib\x64" "/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\lib\x64" "/LIBPATH:C:\Program Files (x86)\Windows Kits\NETFxsdk\4.8\lib\um\x64" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.18362.0\ucrt\x64" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.18362.0\um\x64" FV.lib libprotobuf-lite.lib libprotobuf.lib libprotoc.lib c10.lib asmjit.lib clog.lib cpuinfo.lib dnnl.lib fbgemm.lib mkldnn.lib torch.lib torch_cpu.lib /EXPORT:PyInit_pythonmanager_Pybind11 build\temp.win-amd64-3.7\Release\pythonmanager_Pybind11.obj build\temp.win-amd64-3.7\Release\Codes/fac_ver/cpp/port/LibtorchPort/Dependencies/include/messages/Config.pb.obj /OUT:build\lib.win-amd64-3.7\pythonmanager_Pybind11.cp37-win_amd64.pyd /IMPLIB:build\temp.win-amd64-3.7\Release\pythonmanager_Pybind11.cp37-win_amd64.lib
    LINK : error LNK2001: unresolved external symbol PyInit_pythonmanager_Pybind11
    build\temp.win-amd64-3.7\Release\pythonmanager_Pybind11.cp37-win_amd64.lib : Fatal error LNK1120: 1 unresolved externals
    error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\VC\\Tools\\MSVC\\14.27.29110\\bin\\HostX86\\x64\\link.exe' Failed with exit status 1120

我在这里想念什么？

解决方法

好的，我犯了一个愚蠢的错误！似乎在定义PYBIND11_MODULE时，名字和setup()中使用的名称必须与源文件相同，即我的情况是PythonManager_Pybind11.cpp。这就是链接器抱怨实际对象（即主要源文件）的原因。
进行这些更改后，现在一切正常。

这是这些微小更改后的外观：

#include <string>
#include <vector>

#include <torch/script.h>
#include <pybind11/pybind11.h>
namespace py = pybind11;

#include <FV/FV.h>
//template <class T>
class PyManager 
{
public:
    PyManager(std::string model_path,std::string img_bank_folder_root,std::string cache_folder,std::string pnet,std::string rnet,std::string onet,bool rebuildCache)
    {
        auto config = FV::Load_Default_Settings();
        //...
        fv = std::make_shared<FV>(config);
    }


    int AddUser(std::string user_id,std::string img_fldr_path)
    {
        return fv->AddNewUser(user_id,img_fldr_path);
    }
    int RemoveUser(std::string user_id)
    {
        return fv->RemoveUser(user_id);
    }
    int UpdateUser(std::string user_id,std::string new_images_folder_path)
    {
        return fv->UpdateUser(user_id,new_images_folder_path);
    }
    int UpdateUsersInBulk(std::vector<std::string> userIDs,std::string ID_folders_path,bool is_delete_granted = true,bool show_dbg_info = true)
    {
        return fv->UpdateUsersInBulk(userIDs,ID_folders_path,is_delete_granted,show_dbg_info);

    }
    int RenameId(std::string old_id,std::string new_id)
    {
       return fv->RenameUserID(old_id,new_id);
    }

private:
    std::shared_ptr<FV> fv;
};

PYBIND11_MODULE(PythonManager_Pybind11,m) {
    py::class_<PyManager>(m,"Manager")
        .def(py::init<std::string,std::string,bool>())
        .def("add",&PyManager::AddUser)
        .def("remove",&PyManager::RemoveUser)
        .def("update",&PyManager::UpdateUser)
        .def("rename",&PyManager::RenameId)
        .def("update_in_bulk",&PyManager::UpdateUsersInBulk);
}

这就是我构建扩展名（setup.py）的方式：

import os,sys
from os import environ,getcwd
from distutils.core import setup,Extension
from distutils import sysconfig
import getpass 
cpp_args = ['/std:c++17']

user = getpass.getuser()
sfc_module = Extension(
    'PythonManager_Pybind11',sources=['PythonManager_Pybind11.cpp','D:/cpp/port/LibtorchPort/Dependencies/include/messages/Config.pb.cc'],include_dirs=['pybind11/include',f'C:/Users/{user}/Anaconda3/include',f'C:/Users/{user}/Anaconda3/include/pybind11/',"D:/External Libs/Opencv3.4.10_vc14_vc15/opencv3.4/include","D:/cpp/port/LibtorchPort/Dependencies/include","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/include","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/include/torch/csrc/api/include",f'C:/Users/{user}/Anaconda3/Library/include',f'C:/Users/{user}/Anaconda3/Lib/site-packages/numpy/core/include'],library_dirs=[# python3.6.7: f'C:/Users/{user}/Anaconda3/pkgs/openblas-0.3.3-h535eed3_1001/Library/lib',"D:/cpp/port/LibtorchPort/x64/Release","D:/External Libs/Opencv3.4.10_vc14_vc15/opencv3.4/x64/vc14/lib","D:/cpp/port/LibtorchPort/Dependencies/libtorch-release-latest/libtorch/lib",f'C:/Users/{user}/Anaconda3/libs',f'C:/Users/{user}/Anaconda3'],libraries=['FV','libprotobuf-lite','libprotobuf','libprotoc','c10','asmjit','clog','cpuinfo','dnnl','fbgemm','mkldnn','torch','torch_cpu'],language='c++',extra_compile_args=cpp_args,)

setup(
    name='PythonManager_Pybind11',version='1.0',description='Python package with PythonExtension C++ extension (PyBind11)',ext_modules=[sfc_module],)

现在正在执行：
pip wheel .或pip install -e .可以很好地建立扩展名。