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问使用gcc构建pybind11项目时获取未定义的引用
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Stack Overflow用户

提问于 2020-04-06 16:46:53

回答 1查看 4.3K关注 0票数 2

我试图在Linux中构建一个C++静态库(在我的例子中是Ubuntu18.04)，使用Makefile使用GCC。我注意到问题不在makefile本身，而是我试图与GCC一起编译和构建的方式。在我进一步解释GCC方面之前，下面是我当前的项目层次结构。

该项目只使用驻留在Pybind11目录中的External_Libraries标头库。

我的类定义和实现，命名Core.h和Core.cpp与包含一些实用函数的py_utilities.h和any.hpp一起驻留在Internal_libraries中。(这两个文件不使用)。最后，使用test_lib.cpp的Core.h驻留在根目录中。

这就是它的样子：

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

现在，正如您所看到的，这个项目依赖于Pybind11包含目录，也依赖于<Python.h> + pythons目录。在试图构建静态库或普通可执行文件时，我都会遇到相同的未定义错误。我包括GCC所需的搜索路径(包括和库)如下：

构建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 ./Internal_Libraries/Core.cpp -o Core.o

构建test_lib.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：

构建test_lib可执行文件：

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，我得到了许多未定义的错误，我猜这些错误与链接器有关，但是我提供了所需的路径，所以我不知道哪里出了问题！

以下是我所犯的错误：

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

下面是指向完整错误日志的链接：错误日志

如果Core.h的内容在这里很重要，则如下所示：

#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，现在我正尝试使用GCC在Linux上做同样的事情。很明显，我好像做错了什么，但我似乎不知道自己哪里出了问题。我在这里错过了什么？

更新

在手动编译链接之后，我完成了以下操作：

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，我从上面的命令中删除了shared关键字，这样它就不会创建共享库了！尽管如此，最后一个命令仍然会导致链接器错误：

 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

看一下这些错误，在我看来，问题似乎不是pybind11本身，而是Python库。PyObject_Str、PyObject_Str、PyImport_ImportModule、PyProperty_Type等都是Python。不过，我提供了Python，特别是libs目录，因此g++应该能够找到库并链接它们。我不明白为什么这不管用。这里少了什么？

我甚至创建了一个bash文件，并尝试了我找到的所有路径，但都没有结果：

#!/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

g++

python-c-api

pybind11

c++

回答 1

Stack Overflow用户

回答已采纳

发布于 2020-04-07 17:11:56

简短答覆：

正如我所说，链接器错误与找不到Python库有关。为了获得成功的构建，因此只需要包含该库，因此最终的构建命令是：

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

这简单地编译和链接所有的对象文件在一起，并解决这个问题。

更多解释：

您可以通过导航到Python目录，或者只需在终端中执行python3-config --ldflags或python3.7-config --ldflags (如果有多个安装，则取决于您版本的python )。(谢谢@ChrisD)。

但是，为了使可执行文件正确运行，lib文件夹需要位于PATH中，或者可以使用ldconfig加载所需的库。*我也必须这样做：

sudo ldconfig /home/rika/anaconda3/lib/

附带说明：

我还发现本网站在链接过程中非常有用。我还试图直接使用图书馆，即：

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！

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/61064801

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