在导入Cython生成的.so文件时，这个importterror的含义是什么?

Question

我正在浏览Cython文档并构建每个示例应用程序。我有点卡在使用C库。在成功构建.so文件并尝试将其导入到名为test.py的python文件中之后，会抛出以下错误。

$ python3.2 test.py 
Traceback (most recent call last):
  File "test.py", line 12, in <module>
    from queue import Queue
ImportError: dlopen(/Users/jeremy/Development/labs/python/cython_lib_wrapper/queue.so, 2): Symbol not found: _queue_free
  Referenced from: /Users/jeremy/Development/labs/python/cython_lib_wrapper/queue.so
  Expected in: flat namespace
 in /Users/jeremy/Development/labs/python/cython_lib_wrapper/queue.so

.so文件位于test.py文件旁边。所以，似乎应该找到它。这是运行最新版本的Cython，在OSX 10.6上使用Python 3.2。

见解吗?

编辑-添加构建命令和输出

$ python3.2 setup.py build_ext --inplace
running build_ext
cythoning queue.pyx to queue.c
building 'queue' extension
gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -O3 -isysroot /Developer/SDKs/MacOSX10.6.sdk -arch i386 -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.6.sdk -I/Library/Frameworks/Python.framework/Versions/3.2/include/python3.2m -c queue.c -o build/temp.macosx-10.6-intel-3.2/queue.o
    queue.c: In function ‘__pyx_f_5queue_5Queue_append’:
    queue.c:627: warning: cast to pointer from integer of different size
    queue.c: In function ‘__pyx_f_5queue_5Queue_extend’:
    queue.c:740: warning: cast to pointer from integer of different size
    queue.c: In function ‘__pyx_f_5queue_5Queue_peek’:
    queue.c:813: warning: cast from pointer to integer of different size
    queue.c: In function ‘__pyx_f_5queue_5Queue_pop’:
    queue.c:965: warning: cast from pointer to integer of different size
    gcc-4.2 -bundle -undefined dynamic_lookup -arch i386 -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.6.sdk -isysroot /Developer/SDKs/MacOSX10.6.sdk -g build/temp.macosx-10.6-intel-3.2/queue.o -o 

编辑2 -在注释中添加"otool" cmd

queue.so:
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.0)

编辑3 -添加"nm"输出

U ___stack_chk_fail
U ___stack_chk_guard
U _queue_free
U _queue_is_empty
U _queue_new
U _queue_peek_head
U _queue_pop_head
U _queue_push_tail
U dyld_stub_binder

grep命令输出如下:

(undefined) external _queue_free (dynamically looked up)

Answer 1

EDIT:

啊，你没有提到你对libcalg中的代码有依赖。当你构建c扩展时，这些东西需要被编译和包含。

修改setup.py:

# setup.py
# ...
ext_modules = [Extension("queue", ["queue.pyx", "libcalg/queue.c"])]
# ...

---

我们可以后退一步，看看你是否可以建立一个非常简单的例子:

我尝试了以下3个文件，myext。Pyx, test.py, setup.py)，它似乎工作得很好。当然，我是在OS X 10.7上，所以它与你的环境不完全相同。为了排除差异，也许您可以复制这些并构建它们作为完整性检查。

myext.pyx目录:

# myext.pyx
def square(x):
    return x * x

test.py的内容

# test.py
from myext import square
print "%d squared is %d"%(4, square(4))

setup.py:

# setup.py
from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext
ext_modules = [Extension("myext", ["myext.pyx"])]
setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': build_ext},
  ext_modules = ext_modules
)

我在包含这3个文件的目录中构建:

cython_test$ /usr/bin/python setup.py build_ext --inplace 
running build_ext
cythoning myext.pyx to myext.c
building 'myext' extension
creating build
creating build/temp.macosx-10.7-intel-2.7
llvm-gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch x86_64 -pipe -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c myext.c -o build/temp.macosx-10.7-intel-2.7/myext.o
llvm-gcc-4.2 -Wl,-F. -bundle -undefined dynamic_lookup -Wl,-F. -arch i386 -arch x86_64 build/temp.macosx-10.7-intel-2.7/myext.o -o /Users/steder/SO/cython_test/myext.so
cython_test$ python test.py
4 squared is 16:

我的环境有类似的otool输出，并且DYLD_LIBRARY_PATH也未设置，但是nm -m显示的是定义的平方。

专:

00000000000011d0 (__DATA,__data) non-external ___pyx_k__square
00000000000011e0 (__DATA,__data) non-external ___pyx_mdef_5myext_square
0000000000001218 (__DATA,__bss) non-external ___pyx_n_s__square
0000000000000c80 (__TEXT,__text) non-external ___pyx_pf_5myext_square

请尝试一下，看看nm -m在您的环境中显示了什么