导入cython函数：属性错误：'module'对象没有'fun'属性

Question

我写了一个小的cython代码

#t3.pyx
from libc.stdlib cimport atoi

cdef int fun(char *s):
        return atoi(s)

setup.py文件是

from distutils.core import setup
from Cython.Build import cythonize

setup(ext_modules=cythonize("t3.pyx"))

我使用这个命令运行setup.py

python setup.py build_ext --inplace

这给了我

Compiling t3.pyx because it changed.
Cythonizing t3.pyx
running build_ext
building 't3' extension
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-     prototypes -fno-strict-aliasing -D_FORTIFY_SOURCE=2 -g -fstack-protector-  strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c    t3.c -o build/temp.linux-x86_64-2.7/t3.o
t3.c:556:12: warning: ‘__pyx_f_2t3_fun’ defined but not used [-Wunused-function]
 static int __pyx_f_2t3_fun(char *__pyx_v_s) {
        ^
x86_64-linux-gnu-gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-Bsymbolic-functions -Wl,-z,relro -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -Wl,-Bsymbolic-functions -Wl,-z,relro -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security build/temp.linux-x86_64-2.7/t3.o -o /home/debesh/Documents/cython/t3/t3.so

当我运行python解释器时，它显示我

>>> import t3
>>> t3.fun('1234')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'fun'
>>> 

Answer 1

这里的问题是您用cdef而不是def来定义方法。cdef方法只能从cython代码调用。

您可以在文档的Python functions vs. C functions部分找到详细信息。

Python functions are defined using the def statement, as in Python. They take Python objects as parameters and return Python objects.

C functions are defined using the new cdef statement. They take either Python objects or C values as parameters, and can return either Python objects or C values.

重要的是：

Within a Cython module, Python functions and C functions can call each other freely, but only Python functions can be called from outside the module by interpreted Python code. So, any functions that you want to “export” from your Cython module must be declared as Python functions using def.