尝试使用 Cython 扩展时未定义的符号
Undefined symbols when trying to use Cython Extensions
我确信我遗漏了一些简单的东西，但我已经盯着它看了很长时间以至于我不会看到它。我已经阅读了问题和答案 here, here, here, , and ，但没有遇到适合我的用例的解决方案。我正在尝试组合一个简单的测试结构来玩智能指针和 cython（尽管我什至无法进入智能指针部分）。代码如下：
test_unique_ptr.h
struct TestStruct {
int a;
int b;
};
class TestClass
{
public:
TestClass(void);
~TestClass(void);
TestStruct myts;
int getA() { return myts.a; }
int getB() { return myts.b; }
};
test_unique_ptr.cpp
#include "test_unique_ptr.h"
TestClass::TestClass(void) {
myts.a = 4;
myts.b = 7;
}
这会成功编译成libTestUPtr.so
test_u_ptr.pyx
from libcpp.memory cimport unique_ptr
from cython.operator cimport dereference as deref
cdef extern from "test_unique_ptr.h":
ctypedef struct TestStruct:
int a
int b
cdef cppclass TestClass:
TestClass()
TestStruct foo
int getA()
int getB()
cdef class TestClass1:
cdef:
TestClass tc
def __cinit__(self):
self.tc = TestClass()
def getValue(self):
print(self.tc.getA())
foo = TestClass1()
foo.getValue()
setup.py
from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext
import numpy
setup(
cmdclass = {'build_ext': build_ext},
ext_modules = [
Extension("test_u_ptr",
language="c++",
sources=["test_u_ptr.pyx"],
include_dirs=["/home/share/data/code/python/test/include", numpy.get_include()],
libraries = ["TestUPtr"],
library_dirs=["/home/share/data/code/python/test/lib"],
extra_compile_args=['-lstdc++','-std=c++11', '-v'],
extra_link_args=['-lstdc++', '-v'],
)
]
)
这也成功编译成test_u_ptr.cpython-35m-x86_64-linux-gnu.so。现在是有趣的部分。
$ python3
>>> import test_u_ptr
ImportError: /home/share/data/code/python/test/test_u_ptr.cpython-35m-x86_64-linux-gnu.so: undefined symbol: _ZN9TestClassD1Ev
符号似乎在 libTestUPtr.so
中正确定义
$ nm -C libTestUPtr.so
0000000000201030 B __bss_start
0000000000201030 b completed.6973
w __cxa_finalize
0000000000000580 t deregister_tm_clones
00000000000005f0 t __do_global_dtors_aux
0000000000200e38 t __do_global_dtors_aux_fini_array_entry
0000000000201028 d __dso_handle
0000000000200e48 d _DYNAMIC
0000000000201030 D _edata
0000000000201038 B _end
0000000000000680 T _fini
0000000000000630 t frame_dummy
0000000000200e30 t __frame_dummy_init_array_entry
0000000000000700 r __FRAME_END__
0000000000201000 d _GLOBAL_OFFSET_TABLE_
w __gmon_start__
0000000000000530 T _init
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
0000000000200e40 d __JCR_END__
0000000000200e40 d __JCR_LIST__
w _Jv_RegisterClasses
00000000000005b0 t register_tm_clones
0000000000201030 d __TMC_END__
0000000000000670 T TestClass::TestClass()
0000000000000670 T TestClass::TestClass()
然而，几乎所有东西在 cython 库中都是未定义的。
$ nm -C test_u_ptr.cpython-35m-x86_64-linux-gnu.so
0000000000204530 B __bss_start
0000000000204540 b completed.6973
w __cxa_finalize@@GLIBC_2.2.5
0000000000001be0 t deregister_tm_clones
0000000000001c50 t __do_global_dtors_aux
0000000000203d40 t __do_global_dtors_aux_fini_array_entry
0000000000204180 d __dso_handle
0000000000203d50 d _DYNAMIC
0000000000204530 D _edata
00000000002046f8 B _end
0000000000003154 T _fini
0000000000001c90 t frame_dummy
0000000000203d38 t __frame_dummy_init_array_entry
00000000000035b8 r __FRAME_END__
0000000000204000 d _GLOBAL_OFFSET_TABLE_
w __gmon_start__
00000000000015e8 T _init
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
0000000000203d48 d __JCR_END__
0000000000203d48 d __JCR_LIST__
w _Jv_RegisterClasses
U PyBaseObject_Type
U PyBytes_FromStringAndSize
U PyCapsule_New
U PyCFunction_Type
U _Py_CheckRecursionLimit
U _Py_CheckRecursiveCall
U PyCode_New
U PyDict_GetItem
U PyDict_GetItemString
U PyDict_New
U PyDict_SetItem
U PyDict_SetItemString
U PyErr_Format
U PyErr_Occurred
U PyErr_SetString
U PyErr_WarnEx
U PyEval_EvalCodeEx
U PyEval_EvalFrameEx
U PyExc_ImportError
U PyExc_NameError
U PyExc_SystemError
U PyExc_TypeError
U PyFrame_New
U PyFunction_Type
U Py_GetVersion
U PyImport_AddModule
U PyImport_GetModuleDict
00000000000023d0 T PyInit_test_u_ptr
U PyLong_FromLong
U PyMem_Malloc
U PyMem_Realloc
U PyMethod_Type
U PyModule_Create2
U PyModule_GetDict
U _Py_NoneStruct
U PyObject_Call
U PyObject_CallFinalizerFromDealloc
U PyObject_GetAttr
U PyObject_SetAttrString
U PyOS_snprintf
U PyThreadState_Get
U PyTraceBack_Here
U PyTuple_New
U PyTuple_Pack
U PyType_Ready
U PyUnicode_Decode
U PyUnicode_FromFormat
U PyUnicode_FromString
U PyUnicode_FromStringAndSize
U PyUnicode_InternFromString
0000000000204560 B __pyx_module_is_main_test_u_ptr
0000000000001c10 t register_tm_clones
U __stack_chk_fail@@GLIBC_2.4
0000000000204530 d __TMC_END__
000000000000333b r __pyx_k_end
0000000000003337 r __pyx_k_foo
0000000000204650 b __pyx_print
0000000000003332 r __pyx_k_file
0000000000003329 r __pyx_k_main
0000000000003320 r __pyx_k_test
00000000002046a0 b __pyx_lineno
0000000000204690 b __pyx_clineno
000000000000331a r __pyx_k_print
0000000000204580 b __pyx_methods
0000000000204630 b __pyx_n_s_end
0000000000204620 b __pyx_n_s_foo
0000000000204680 b __pyx_filename
0000000000204628 b __pyx_n_s_file
0000000000204600 b __pyx_n_s_main
00000000002045d0 b __pyx_n_s_test
0000000000204320 d __pyx_moduledef
00000000002045f0 b __pyx_n_s_print
0000000000204660 b __pyx_code_cache
0000000000003311 r __pyx_k_getValue
00000000002041a0 d __pyx_string_tab
00000000002046b0 b __pyx_empty_bytes
00000000002046c0 b __pyx_empty_tuple
0000000000001e10 t __Pyx_AddTraceback(char const*, int, int, char const*)
0000000000003302 r __pyx_k_pyx_vtable
0000000000204610 b __pyx_n_s_getValue
00000000002046a8 b __pyx_empty_unicode
00000000000018e0 t __Pyx_PyObject_Call(_object*, _object*, _object*)
00000000002045e0 b __pyx_n_s_pyx_vtable
00000000000019c1 t __Pyx_PyFunction_FastCallDict(_object*, _object**, int, _object*) [clone .constprop.3]
00000000002043a0 d __pyx_type_10test_u_ptr_TestClass1
0000000000204640 b __pyx_ptype_10test_u_ptr_TestClass1
0000000000001d30 t __pyx_tp_new_10test_u_ptr_TestClass1(_typeobject*, _object*, _object*)
00000000002045c0 b __pyx_vtable_10test_u_ptr_TestClass1
00000000002045a0 b __pyx_methods_10test_u_ptr_TestClass1
0000000000204670 b __pyx_vtabptr_10test_u_ptr_TestClass1
0000000000001ce0 t __pyx_tp_dealloc_10test_u_ptr_TestClass1(_object*)
0000000000002230 t __pyx_f_10test_u_ptr_10TestClass1_getValue(__pyx_obj_10test_u_ptr_TestClass1*)
0000000000001cd0 t __pyx_f_10test_u_ptr_10TestClass1_printValue(__pyx_obj_10test_u_ptr_TestClass1*)
00000000002046d0 b __pyx_b
00000000002046e0 b __pyx_d
00000000002046f0 b __pyx_m
U TestClass::TestClass()
U TestClass::~TestClass()
两个库都是 64 位的。
$ file libTestUPtr.so
libTestUPtr.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=4c6eb8560a244ebd485d483f1c27004145ad1882, not stripped
$ file test_u_ptr.cpython-35m-x86_64-linux-gnu.so
test_u_ptr.cpython-35m-x86_64-linux-gnu.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=5a2daa515d4a22dd46484968e817cd3a3bcebe5a, not stripped
libTestUPtr.so 在 LD_LIBRARY_PATH 并且在正确的位置
$ echo $LD_LIBRARY_PATH
/home/share/data/code/python/test/lib
$ ls /home/share/data/code/python/test/lib/
libTestUPtr.so
我不知道发生了什么事。任何见解将不胜感激。
gcc 是 4.8.4 版。 Python 是版本 3.5.3。 Cython 是版本 0.25.2.
你的问题没有什么神秘的，我怀疑添加 --no-undefined 已经解决了它。
遗漏的符号是 class TestClass 的析构函数。您的共享库为 TestClass 提供了两个符号：但是这两个符号都是构造函数（我不完全理解为什么有两个以及为什么两个符号具有相同的地址）并且其中的 none 是需要析构函数。
这个问题的根源是你声明了你的析构函数，所以它不再被编译器默认实现，但你没有在 cpp 文件中提供实现。
所以你的选择是：
从h文件中删除析构函数的声明，让编译器来处理。
在 cpp 文件中实现你的析构函数。
哪个更好看语境
gcc 为构造函数发出两个符号，为析构函数发出两个符号，这似乎是一个已知的遗漏优化，here is a great explanation。
地址相同，因为编译器为两种相同的方法设置了别名：
_ZN9TestClassC2Ev: //Constructor of the BaseObject-constructor
.LFB3:
...
ret
.LFE3:
..
.globl _ZN9TestClassC1Ev
.set _ZN9TestClassC1Ev,_ZN9TestClassC2Ev //HERE WE GO, Complete Object constructor which we use normally
我确信我遗漏了一些简单的东西，但我已经盯着它看了很长时间以至于我不会看到它。我已经阅读了问题和答案 here, here, here,
test_unique_ptr.h
struct TestStruct {
int a;
int b;
};
class TestClass
{
public:
TestClass(void);
~TestClass(void);
TestStruct myts;
int getA() { return myts.a; }
int getB() { return myts.b; }
};
test_unique_ptr.cpp
#include "test_unique_ptr.h"
TestClass::TestClass(void) {
myts.a = 4;
myts.b = 7;
}
这会成功编译成libTestUPtr.so
test_u_ptr.pyx
from libcpp.memory cimport unique_ptr
from cython.operator cimport dereference as deref
cdef extern from "test_unique_ptr.h":
ctypedef struct TestStruct:
int a
int b
cdef cppclass TestClass:
TestClass()
TestStruct foo
int getA()
int getB()
cdef class TestClass1:
cdef:
TestClass tc
def __cinit__(self):
self.tc = TestClass()
def getValue(self):
print(self.tc.getA())
foo = TestClass1()
foo.getValue()
setup.py
from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext
import numpy
setup(
cmdclass = {'build_ext': build_ext},
ext_modules = [
Extension("test_u_ptr",
language="c++",
sources=["test_u_ptr.pyx"],
include_dirs=["/home/share/data/code/python/test/include", numpy.get_include()],
libraries = ["TestUPtr"],
library_dirs=["/home/share/data/code/python/test/lib"],
extra_compile_args=['-lstdc++','-std=c++11', '-v'],
extra_link_args=['-lstdc++', '-v'],
)
]
)
这也成功编译成test_u_ptr.cpython-35m-x86_64-linux-gnu.so。现在是有趣的部分。
$ python3
>>> import test_u_ptr
ImportError: /home/share/data/code/python/test/test_u_ptr.cpython-35m-x86_64-linux-gnu.so: undefined symbol: _ZN9TestClassD1Ev
符号似乎在 libTestUPtr.so
中正确定义$ nm -C libTestUPtr.so
0000000000201030 B __bss_start
0000000000201030 b completed.6973
w __cxa_finalize
0000000000000580 t deregister_tm_clones
00000000000005f0 t __do_global_dtors_aux
0000000000200e38 t __do_global_dtors_aux_fini_array_entry
0000000000201028 d __dso_handle
0000000000200e48 d _DYNAMIC
0000000000201030 D _edata
0000000000201038 B _end
0000000000000680 T _fini
0000000000000630 t frame_dummy
0000000000200e30 t __frame_dummy_init_array_entry
0000000000000700 r __FRAME_END__
0000000000201000 d _GLOBAL_OFFSET_TABLE_
w __gmon_start__
0000000000000530 T _init
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
0000000000200e40 d __JCR_END__
0000000000200e40 d __JCR_LIST__
w _Jv_RegisterClasses
00000000000005b0 t register_tm_clones
0000000000201030 d __TMC_END__
0000000000000670 T TestClass::TestClass()
0000000000000670 T TestClass::TestClass()
然而，几乎所有东西在 cython 库中都是未定义的。
$ nm -C test_u_ptr.cpython-35m-x86_64-linux-gnu.so
0000000000204530 B __bss_start
0000000000204540 b completed.6973
w __cxa_finalize@@GLIBC_2.2.5
0000000000001be0 t deregister_tm_clones
0000000000001c50 t __do_global_dtors_aux
0000000000203d40 t __do_global_dtors_aux_fini_array_entry
0000000000204180 d __dso_handle
0000000000203d50 d _DYNAMIC
0000000000204530 D _edata
00000000002046f8 B _end
0000000000003154 T _fini
0000000000001c90 t frame_dummy
0000000000203d38 t __frame_dummy_init_array_entry
00000000000035b8 r __FRAME_END__
0000000000204000 d _GLOBAL_OFFSET_TABLE_
w __gmon_start__
00000000000015e8 T _init
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
0000000000203d48 d __JCR_END__
0000000000203d48 d __JCR_LIST__
w _Jv_RegisterClasses
U PyBaseObject_Type
U PyBytes_FromStringAndSize
U PyCapsule_New
U PyCFunction_Type
U _Py_CheckRecursionLimit
U _Py_CheckRecursiveCall
U PyCode_New
U PyDict_GetItem
U PyDict_GetItemString
U PyDict_New
U PyDict_SetItem
U PyDict_SetItemString
U PyErr_Format
U PyErr_Occurred
U PyErr_SetString
U PyErr_WarnEx
U PyEval_EvalCodeEx
U PyEval_EvalFrameEx
U PyExc_ImportError
U PyExc_NameError
U PyExc_SystemError
U PyExc_TypeError
U PyFrame_New
U PyFunction_Type
U Py_GetVersion
U PyImport_AddModule
U PyImport_GetModuleDict
00000000000023d0 T PyInit_test_u_ptr
U PyLong_FromLong
U PyMem_Malloc
U PyMem_Realloc
U PyMethod_Type
U PyModule_Create2
U PyModule_GetDict
U _Py_NoneStruct
U PyObject_Call
U PyObject_CallFinalizerFromDealloc
U PyObject_GetAttr
U PyObject_SetAttrString
U PyOS_snprintf
U PyThreadState_Get
U PyTraceBack_Here
U PyTuple_New
U PyTuple_Pack
U PyType_Ready
U PyUnicode_Decode
U PyUnicode_FromFormat
U PyUnicode_FromString
U PyUnicode_FromStringAndSize
U PyUnicode_InternFromString
0000000000204560 B __pyx_module_is_main_test_u_ptr
0000000000001c10 t register_tm_clones
U __stack_chk_fail@@GLIBC_2.4
0000000000204530 d __TMC_END__
000000000000333b r __pyx_k_end
0000000000003337 r __pyx_k_foo
0000000000204650 b __pyx_print
0000000000003332 r __pyx_k_file
0000000000003329 r __pyx_k_main
0000000000003320 r __pyx_k_test
00000000002046a0 b __pyx_lineno
0000000000204690 b __pyx_clineno
000000000000331a r __pyx_k_print
0000000000204580 b __pyx_methods
0000000000204630 b __pyx_n_s_end
0000000000204620 b __pyx_n_s_foo
0000000000204680 b __pyx_filename
0000000000204628 b __pyx_n_s_file
0000000000204600 b __pyx_n_s_main
00000000002045d0 b __pyx_n_s_test
0000000000204320 d __pyx_moduledef
00000000002045f0 b __pyx_n_s_print
0000000000204660 b __pyx_code_cache
0000000000003311 r __pyx_k_getValue
00000000002041a0 d __pyx_string_tab
00000000002046b0 b __pyx_empty_bytes
00000000002046c0 b __pyx_empty_tuple
0000000000001e10 t __Pyx_AddTraceback(char const*, int, int, char const*)
0000000000003302 r __pyx_k_pyx_vtable
0000000000204610 b __pyx_n_s_getValue
00000000002046a8 b __pyx_empty_unicode
00000000000018e0 t __Pyx_PyObject_Call(_object*, _object*, _object*)
00000000002045e0 b __pyx_n_s_pyx_vtable
00000000000019c1 t __Pyx_PyFunction_FastCallDict(_object*, _object**, int, _object*) [clone .constprop.3]
00000000002043a0 d __pyx_type_10test_u_ptr_TestClass1
0000000000204640 b __pyx_ptype_10test_u_ptr_TestClass1
0000000000001d30 t __pyx_tp_new_10test_u_ptr_TestClass1(_typeobject*, _object*, _object*)
00000000002045c0 b __pyx_vtable_10test_u_ptr_TestClass1
00000000002045a0 b __pyx_methods_10test_u_ptr_TestClass1
0000000000204670 b __pyx_vtabptr_10test_u_ptr_TestClass1
0000000000001ce0 t __pyx_tp_dealloc_10test_u_ptr_TestClass1(_object*)
0000000000002230 t __pyx_f_10test_u_ptr_10TestClass1_getValue(__pyx_obj_10test_u_ptr_TestClass1*)
0000000000001cd0 t __pyx_f_10test_u_ptr_10TestClass1_printValue(__pyx_obj_10test_u_ptr_TestClass1*)
00000000002046d0 b __pyx_b
00000000002046e0 b __pyx_d
00000000002046f0 b __pyx_m
U TestClass::TestClass()
U TestClass::~TestClass()
两个库都是 64 位的。
$ file libTestUPtr.so
libTestUPtr.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=4c6eb8560a244ebd485d483f1c27004145ad1882, not stripped
$ file test_u_ptr.cpython-35m-x86_64-linux-gnu.so
test_u_ptr.cpython-35m-x86_64-linux-gnu.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=5a2daa515d4a22dd46484968e817cd3a3bcebe5a, not stripped
libTestUPtr.so 在 LD_LIBRARY_PATH 并且在正确的位置
$ echo $LD_LIBRARY_PATH
/home/share/data/code/python/test/lib
$ ls /home/share/data/code/python/test/lib/
libTestUPtr.so
我不知道发生了什么事。任何见解将不胜感激。
gcc 是 4.8.4 版。 Python 是版本 3.5.3。 Cython 是版本 0.25.2.
你的问题没有什么神秘的，我怀疑添加 --no-undefined 已经解决了它。
遗漏的符号是 class TestClass 的析构函数。您的共享库为 TestClass 提供了两个符号：但是这两个符号都是构造函数（我不完全理解为什么有两个以及为什么两个符号具有相同的地址）并且其中的 none 是需要析构函数。
这个问题的根源是你声明了你的析构函数，所以它不再被编译器默认实现，但你没有在 cpp 文件中提供实现。
所以你的选择是：
从h文件中删除析构函数的声明，让编译器来处理。
在 cpp 文件中实现你的析构函数。
哪个更好看语境
gcc 为构造函数发出两个符号，为析构函数发出两个符号，这似乎是一个已知的遗漏优化，here is a great explanation。
地址相同，因为编译器为两种相同的方法设置了别名：
_ZN9TestClassC2Ev: //Constructor of the BaseObject-constructor
.LFB3:
...
ret
.LFE3:
..
.globl _ZN9TestClassC1Ev
.set _ZN9TestClassC1Ev,_ZN9TestClassC2Ev //HERE WE GO, Complete Object constructor which we use normally