与介子和 boost_python 链接错误

Question

我正在尝试使用 boost 将 c++ class 暴露给 python，但我无法弄清楚我得到的链接错误。

我的演示程序如下所示：

#include <boost/python.hpp>
#include <Python.h>

char const* greet()
{
   return "hello, world";
}

BOOST_PYTHON_MODULE(hello_ext)
{
    using namespace boost::python;
    def("greet", greet);
}

我的介子文件如下所示：

project('test', 'cpp', version : '0.0.1',default_options : ['c_args= -g'])
add_project_arguments(language : 'cpp')
cxx = meson.get_compiler('cpp')
python_dep = dependency('python3')
boost_dep = dependency('boost',modules: ['python3'],)

src = ['./test.cpp']

executable('test', src,
                     dependencies : [ python_dep,boost_dep])

当我运行它时，我得到一堆对 python 方法的未定义引用：

/usr/include/boost/python/object_core.hpp:400: undefined reference to `_Py_NoneStruct'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_ValueError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_AsLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceFloorDivide'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyBool_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_GetAttr'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_GetItemString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_Call'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_And'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_IndexError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyEval_GetGlobals'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyTuple_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceSubtract'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_GetAttrString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyModule_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyMem_Free'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyType_IsSubtype'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyStaticMethod_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_WarnEx'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_InternFromString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyTuple_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_SetAttr'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_IsInstance'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_NoMemory'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_AttributeError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Add'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_FromFormat'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_Append'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyType_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_ReferenceError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyArg_ParseTupleAndKeywords'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyStaticMethod_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceMultiply'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyTuple_Size'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_SetObject'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `_PyObject_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Keys'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyType_GenericAlloc'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_Format'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_CallFunction'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_Reverse'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyCFunction_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_OverflowError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyMem_Malloc'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_ExceptionMatches'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyComplex_ImagAsDouble'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyImport_ImportModule'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyProperty_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_FromString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceOr'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyBytes_Size'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyType_GetFlags'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_DelItem'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_FloorDivide'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_Clear'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyRun_StringFlags'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_GetItem'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyWeakref_NewRef'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Multiply'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `_Py_NewReference'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Lshift'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_SetString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Update'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PySlice_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyRun_FileExFlags'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_SetItem'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_AsUTF8'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_SetAttrString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_FromEncodedObject'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_AsUnsignedLongLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_RuntimeError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Xor'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyBytes_AsString'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `_Py_NotImplementedStruct'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Rshift'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyBaseObject_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_StopIteration'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_GetItem'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyExc_TypeError'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Values'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `_Py_fopen'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyType_Ready'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_Size'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyMethod_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyMethod_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_ClearWeakRefs'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_AsSsize_t'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_AsLongLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyEval_CallFunction'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Remainder'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_FromLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_NewException'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_CallMethod'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Or'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_IsTrue'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_Sort'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyModule_Create2'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_AsWideChar'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_AsUnsignedLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceRemainder'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyErr_Occurred'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Copy'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceAnd'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceXor'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `_PyType_Lookup'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Size'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceRshift'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyFloat_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyIter_Next'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyCallable_Check'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyComplex_RealAsDouble'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyLong_FromUnsignedLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyList_Insert'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyObject_RichCompare'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Items'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyCMethod_New'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyTuple_GetItem'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_Subtract'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyComplex_Type'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_AsUTF8String'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyUnicode_FromStringAndSize'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyDict_Clear'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceLshift'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyBool_FromLong'
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libboost_python39.so.1.74.0: undefined reference to `PyNumber_InPlaceAdd'

我在网上看到了一些关于它是链接顺序的建议，我试过改变依赖数组的顺序但没有运气。

Answer 1

看起来您还需要与 python 链接，因为由于某种原因，它没有被作为 boost python 的dependency('python3')项添加到您的依赖项列表中，应该可以解决这个问题。

Answer 2

从 python3.8 开始，python3.pc 文件不提供将程序链接到嵌入式 python 解释器所需的库标志。 相反，包需要使用 python3-embed，所以你应该使用

python_dep = dependency('python3-embed')

还有两件事：

• 您正在构建 python“模块”（因为您将在 python 中使用您公开的方法 greet()，对吧？），所以您应该使用shared_library()作为目标（不是可执行文件（））
• 根据 python 查找模块的方式 - 库的名称应与您命名的 BOOST_PYTHON_MODULE 完全相同（在最简单的情况下，您可以在此处看到替代方案），因此名称后缀被覆盖（默认为“lib”）

 lib = shared_library('hello_ext',
            src,
            dependencies : [ python_dep, boost_dep],
            name_prefix : '')

所有步骤，以及从另一个路径导入模块的复杂性（例如 import importlib.util）：

% meson build
% ninja -C build
% cd build
$ python3
Python 3.8.10 (default, Nov 26 2021, 20:14:08) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import hello_ext
>>> hello_ext.greet()
'hello, world'
>>>