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c++ - 尝试使用 gcc 构建 pybind11 项目时获取未定义的引用

问题描述

我正在尝试使用 GCC 使用Makefile. 我注意到问题不在于 makefile 本身，而在于我尝试使用 GCC 编译和构建的方式。在我解释 GCC 方面的更多内容之前，这里是我当前的项目层次结构的样子。

该项目使用Pybind11位于External_Libraries目录中的仅标头库。

我的类定义和实现、命名Core.h和Core.cpp驻留Internal_libraries以及py_utilities.h其中any.hpp包含一些实用功能。（虽然没有使用这两个文件）。最后test_lib.cppwhich usesCore.h驻留在根中。

这是它的外观：

MainDirectory  
 ┣ External_Libraries  
 ┃ ┗ Pybind11    
 ┃   ┗ Pybind11    
 ┃     ┗ Include      
 ┃ 
 ┣ Internal_Libraries  
 ┃ ┣Core.h  
 ┃ ┣Core.cpp  
 ┃ ┣py_utilities.h  
 ┃ ┣any.hpp  
 ┃
 ┗test_lib.cpp

现在，如您所见，该项目依赖于Pybind11包含目录<Python.h>以及 pythons lib 目录。当我尝试构建静态库或普通可执行文件时，我都面临同样的未定义错误。我将所需的搜索路径（包括和库）包含到 GCC 中，如下所示：

g++ -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages -c ./Internal_Libraries/Core.cpp -o Core.o

g++ -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages -c test_lib.cpp -o test_lib.o

最后：

g++ -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages test_lib.o Core.o -o test_lib

这是它失败的地方，我得到很多未定义的错误，我猜这些错误与链接器有关，但是我提供了所需的路径，所以我不知道这里出了什么问题！

这些是我得到的错误：

g++ -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages test_lib.o Core.o -o test_lib
test_lib.o: In function `pybind11::cast_error::set_error() const':
test_lib.cpp:(.text._ZNK8pybind1110cast_error9set_errorEv[_ZNK8pybind1110cast_error9set_errorEv]+0x29): undefined reference to `PyExc_RuntimeError'
test_lib.cpp:(.text._ZNK8pybind1110cast_error9set_errorEv[_ZNK8pybind1110cast_error9set_errorEv]+0x34): undefined reference to `PyErr_SetString'
test_lib.o: In function `pybind11::error_scope::error_scope()':
test_lib.cpp:(.text._ZN8pybind1111error_scopeC2Ev[_ZN8pybind1111error_scopeC5Ev]+0x27): undefined reference to `PyErr_Fetch'
test_lib.o: In function `pybind11::error_scope::~error_scope()':

...

Core.o: In function `std::enable_if<((!std::is_floating_point<int>::value)&&std::is_signed<int>::value)&&((sizeof (int))<=(sizeof (long))), pybind11::handle>::type pybind11::detail::type_caster<int, void>::cast<int>(int, pybind11::return_value_policy, pybind11::handle)':
Core.cpp:(.text._ZN8pybind116detail11type_casterIivE4castIiEENSt9enable_ifIXaaaantsrSt17is_floating_pointIT_E5valuesrSt9is_signedIS6_E5valuelestS6_stlENS_6handleEE4typeES6_NS_19return_value_policyESA_[_ZN8pybind116detail11type_casterIivE4castIiEENSt9enable_ifIXaaaantsrSt17is_floating_pointIT_E5valuesrSt9is_signedIS6_E5valuelestS6_stlENS_6handleEE4typeES6_NS_19return_value_policyESA_]+0x2c): undefined reference to `PyLong_FromSsize_t'
Core.o: In function `pybind11::array_t<unsigned char, 16>::ensure(pybind11::handle)':
Core.cpp:(.text._ZN8pybind117array_tIhLi16EE6ensureENS_6handleE[_ZN8pybind117array_tIhLi16EE6ensureENS_6handleE]+0x70): undefined reference to `PyErr_Clear'
Core.o: In function `pybind11::array_t<unsigned char, 16>::raw_array_t(_object*)':
Core.cpp:(.text._ZN8pybind117array_tIhLi16EE11raw_array_tEP7_object[_ZN8pybind117array_tIhLi16EE11raw_array_tEP7_object]+0x26): undefined reference to `PyExc_ValueError'
Core.cpp:(.text._ZN8pybind117array_tIhLi16EE11raw_array_tEP7_object[_ZN8pybind117array_tIhLi16EE11raw_array_tEP7_object]+0x35): undefined reference to `PyErr_SetString'
collect2: error: ld returned 1 exit status

这是完整错误日志的链接：错误日志

如果这里的内容Core.h很重要，它是：

#ifndef CORE_H

#define CORE_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(_CORE_BUILD_DLL)

/* We are building CORE as a Win32 DLL */

 #define CORE_API __declspec(dllexport)

#elif defined(_WIN32) && defined(CORE_DLL)

/* We are calling CORE as a Win32 DLL */

 #define CORE_API __declspec(dllimport)

#elif defined(__GNUC__) && defined(_CORE_BUILD_DLL)

/* We are building CORE as a shared / dynamic library */

#define CORE_API __attribute__((visibility("default")))

#else

/* We are building or calling CORE as a static library */

 #define CORE_API

#endif


#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <memory>
#include <pybind11/pybind11.h>
#include <pybind11/embed.h>
#include <pybind11/numpy.h>
#include <pybind11/stl.h>
#include <pybind11/functional.h>

namespace py = pybind11;
using namespace py::literals;

typedef void(*CallbackFn)(bool, std::string, py::array_t<uint8_t>&);
typedef std::function<void(std::string)> LogFunction;
typedef void * HANDLE;


class CORE_API Core

{
private:
    py::scoped_interpreter guard{};
    py::object serviceUtilsModule;
    py::object cls;
    py::object obj;
    py::object startFunc;
...



public:

    Core();
    Core(bool showFeed);
    Core(LogFunction logInfo);
    Core(LogFunction logInfo, LogFunction logWarning);
    Core(LogFunction logInfo, LogFunction logWarning, LogFunction logDebug);
    Core(LogFunction logInfo, LogFunction logWarning, LogFunction logDebug, std::vector<CallbackFn> callbackList);
...
    ~Core();


    void Start(bool async= false);
    py::list GetCallbacks(void);
...
    static void DefaultLoger(std::string str);
};



extern "C"

{
    //COREAPI wchar_t** GetResults(wchar_t* word, int* length, int threshold = 9);
    CORE_API void Start(bool);
    CORE_API void Stop(void);
    CORE_API void SetCpuAffinity(int mask);
    CORE_API void AddCallback(CallbackFn callback);
    CORE_API void RemoveCallback(CallbackFn callback);
    CORE_API void* GetCallbacks(void);
    CORE_API void DefaultLoger(char* str);

    CORE_API void*  CreateHandle();
    CORE_API void*  GetCurrentHandle();
    CORE_API void   DisposeCurrentHandle();
    CORE_API void   SetCurrentHandle(void* handle);
    CORE_API void*  GetHandle();
    CORE_API void   DisposeHandle(void*);

}



#endif // !CORE_H

该项目在 Windows 和 Visual C++ v14 (VS2015) 下运行良好，现在我正在尝试使用 GCC 在 Linux 中做同样的事情。看来我显然做错了什么，但我似乎不知道我哪里出错了。我在这里想念什么？

更新

在手动编译 pybind11 上点击此链接后，我最终做了：

g++ -O3 -Wall -std=c++11 -fPIC -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages -c ./Internal_Libraries/Core.cpp -o Core.o
g++ -O3 -Wall -std=c++11 -fPIC -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages -c test_lib.cpp -o test_lib.o
g++ -O3 -Wall -std=c++11 -fPIC -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages test_lib.o Core.o -o test_lib

请注意，我shared从上面的命令中删除了关键字，因此它不会创建共享库！话虽如此，最后一个命令仍然给出链接器错误：

 g++ -O3 -Wall -std=c++11 -fPIC -I./External_Libraries/pybind11/pybind11/include -I/home/rika/anaconda3/include/python3.7m -L/home/rika/anaconda3/lib -L/home/rika/anaconda3/lib/python3.7/site-packages test_lib.o -o test_lib
test_lib.o: In function `pybind11_static_get':
test_lib.cpp:(.text.pybind11_static_get[pybind11_static_get]+0x3): undefined reference to `PyProperty_Type'
test_lib.o: In function `pybind11_static_set':
test_lib.cpp:(.text.pybind11_static_set[pybind11_static_set]+0x12): undefined reference to `PyProperty_Type'
test_lib.o: In function `pybind11::cast_error::set_error() const':
test_lib.cpp:(.text._ZNK8pybind1110cast_error9set_errorEv[_ZNK8pybind1110cast_error9set_errorEv]+0x10): undefined reference to `PyExc_RuntimeError'
test_lib.cpp:(.text._ZNK8pybind1110cast_error9set_errorEv[_ZNK8pybind1110cast_error9set_errorEv]+0x1c): undefined reference to `PyErr_SetString'
test_lib.o: In function `pybind11::detail::translate_exception(std::__exception_ptr::exception_ptr)':

...


test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0x9a): undefined reference to `PyTuple_Size'
test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0xaa): undefined reference to `PyTuple_GetItem'
test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0xd3): undefined reference to `PyObject_Str'
test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0x1cc): undefined reference to `PyDict_Contains'
test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0x3c1): undefined reference to `PyDict_Contains'
test_lib.cpp:(.text._ZN8pybind116detail5printENS_5tupleENS_4dictE[_ZN8pybind116detail5printENS_5tupleENS_4dictE]+0x518): undefined reference to `PyImport_ImportModule'
test_lib.o: In function `void pybind11::print<(pybind11::return_value_policy)1, pybind11::list>(pybind11::list&&)':
test_lib.cpp:(.text._ZN8pybind115printILNS_19return_value_policyE1EJNS_4listEEEEvDpOT0_[_ZN8pybind115printILNS_19return_value_policyE1EJNS_4listEEEEvDpOT0_]+0x21): undefined reference to `PyDict_New'
test_lib.o: In function `main':
test_lib.cpp:(.text.startup+0x34): undefined reference to `Core::Core(bool)'
test_lib.cpp:(.text.startup+0x41): undefined reference to `Core::SetCpuAffinity(int)'
test_lib.cpp:(.text.startup+0x4b): undefined reference to `Core::Start(bool)'
test_lib.cpp:(.text.startup+0x5b): undefined reference to `Core::GetCallbacks()'
test_lib.cpp:(.text.startup+0x85): undefined reference to `Core::GetCallbacks()'
test_lib.cpp:(.text.startup+0x107): undefined reference to `PyObject_Str'
collect2: error: ld returned 1 exit status

更新 2

查看错误，在我看来问题不是 pybind11 本身，而是Python 库。PyObject_Str, PyObject_Str, PyImport_ImportModule,PyProperty_Type等都是 Python C API。但是我提供了 Python 包含，尤其是 libs 目录，因此 g++ 应该能够找到这些库并链接它们。我不知道为什么这不起作用。这里缺少什么？

我什至制作了一个 bash 文件并尝试了所有我发现无济于事的路径：

#!/bin/bash  

PYBIND_INCL_DIR=-I/home/rika/Documents/cpp/External_Libraries/pybind11/pybind11/include
PYTHON_INCL_DIR=-I/home/rika/anaconda3/include/python3.7m
PYTHON_INCL_DIR2=-I/home/rika/anaconda3/pkgs/python-3.7.4-h265db76_1/include/python3.7m

PYTHON_LIB_DIRS=-L/home/rika/anaconda3/lib/
PYTHON_LIB_DIRS2=-L/home/rika/anaconda3/lib/python3.7/site-packages/
PYTHON_LIB_DIRS3=-L/home/rika/anaconda3/pkgs/python-3.7.4-h265db76_1/lib/

# echo $PYBIND_INCL_DIR
# echo $PYTHON_INCL_DIR

g++ $PYBIND_INCL_DIR  $PYTHON_INCL_DIR  $PYTHON_LIB_DIRS $PYTHON_LIB_DIRS2 $PYTHON_LIB_DIRS3 -c Core.cpp -o Core.o
g++ $PYBIND_INCL_DIR  $PYTHON_INCL_DIR  $PYTHON_LIB_DIRS $PYTHON_LIB_DIRS2 $PYTHON_LIB_DIRS3 test_lib.cpp Core.o -o test_lib

标签： c++g++python-c-apipybind11

解决方案

简短回答：
正如我所说，链接器错误与未找到 Python 库有关。为了成功构建，因此只需要包含该库，因此最终的构建命令将是：

PYBIND_INCL_DIR=-I/home/rika/Documents/mahsan_FV/cpp/External_Libraries/pybind11/pybind11/include
PYTHON_INCL_DIR=-I/home/rika/anaconda3/include/python3.7m
PYTHON_LIB_DIRS=-L/home/rika/anaconda3/lib/

g++ $PYBIND_INCL_DIR  $PYTHON_INCL_DIR  $PYTHON_LIB_DIRS -c Core.cpp -o Core.o 
g++ $PYBIND_INCL_DIR  $PYTHON_INCL_DIR  $PYTHON_LIB_DIRS test_lib.cpp Core.o -lpython3.7m -o test_lib

这只是将所有目标文件编译并链接在一起并解决了问题。

更多解释：

您可以通过导航到 Python lib 目录或在终端中简单地执行python3-config --ldflags或python3.7-config --ldflags（取决于您的 python 版本，如果您有多个安装）来获得此信息。（谢谢@ChrisD）

但是，为了使可执行文件正常运行，lib 文件夹需要位于 PATH 中，或者也可以ldconfig用来加载所需的库。：我也必须这样做：

sudo ldconfig /home/rika/anaconda3/lib/

旁注：
我还发现这个网站对链接过程很有帮助。我还尝试直接使用以下库：

home/hossein/anaconda3/pkgs/python-3.7.4-h265db76_1/lib/libpython3.7m.a

这导致了错误：

lto1: fatal error: bytecode stream in file ‘/home/rika/anaconda3/pkgs/python-3.7.4-h265db76_1/lib/libpython3.7m.a’ generated with LTO version 6.0 instead of the expected 6.2
compilation terminated.
lto-wrapper: fatal error: g++ returned 1 exit status

证明获得正确链接的唯一方法是使用-lpython3.7m！

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