使用cython

Question

我有以下文件：

helloworld.cpp包含

#include <iostream>                                                     
#include <Python.h>                                                     

void Helloworld(){                                                      
  std::cout << "Hello world!" << "\n";                                  
}

helloworld.pyx包含：

cdef extern from "helloworld.cpp":                                      
    cpdef void Helloworld() 

和setup.py包含：

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

ext = Extension('helloworld', sources=["helloworld.pyx"], language="c++")                                                                      

setup(name="helloworld", ext_modules = cythonize([ext]))

当我在Ipython中运行以下命令时，它正确构建

In [1]: run setup.py build_ext --inplace --verbose
running build_ext
building 'helloworld' extension
gcc -pthread -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/ash/anaconda2/envs/python3/include/python3.5m -c helloworld.cpp -o build/temp.linux-x86_64-3.5/helloworld.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
g++ -pthread -shared -L/home/ash/anaconda2/envs/python3/lib -Wl,-rpath=/home/ash/anaconda2/envs/python3/lib,--no-as-needed build/temp.linux-x86_64-3.5/helloworld.o -L/home/ash/anaconda2/envs/python3/lib -lpython3.5m -o /home/ash/CallingC++fromPython/Cython/HelloWorld/helloworld.cpython-35m-x86_64-linux-gnu.so

但是当我尝试导入它时，我收到以下错误：

In [2]: import helloworld
------------------------------------------------------------------------
ImportError                            Traceback (most recent call last)
<ipython-input-12-9f213747d34d> in <module>()
----> 1 import helloworld

ImportError: dynamic module does not define module export function (PyInit_helloworld)

我也尝试了以下内容：

helloworld.pyx包含：

cdef extern from "helloworld.cpp":                                      
    void Helloworld()

def C_Helloworld():
    return Helloworld()

在我尝试构建它的情况下，我得到：

run setup.py build_ext --inplace --verbose
running build_ext
building 'helloworld' extension
gcc -pthread -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/ash/anaconda2/envs/python3/include/python3.5m -c helloworld.cpp -o build/temp.linux-x86_64-3.5/helloworld.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
In file included from helloworld.cpp:458:0,
                 from helloworld.cpp:458,
                 from helloworld.cpp:458,
                 from helloworld.cpp:458,
...
                 from helloworld.cpp:458,
                 from helloworld.cpp:458,
                 from helloworld.cpp:458:
helloworld.cpp:16:20: error: #include nested too deeply
helloworld.cpp:23:20: error: #include nested too deeply
helloworld.cpp:163:27: error: #include nested too deeply
In file included from helloworld.cpp:458:0,
                 from helloworld.cpp:458,
                 from helloworld.cpp:458,
...

暗示它是递归调用的。

Answer 1

我认为这是因为你的模块是空的并且没有定义任何功能。

Cython不会创建包装器。你必须告诉他如何使用你的c ++函数。

您的＆＃34; .pyx＆＃34;的内容文件通常位于＆＃34; .pxd＆＃34;文件。 ＆＃34; .pyx＆＃34; file包含将从python调用的函数。示例：

def hello_world():
    Helloworld()

Answer 2

问题是双重的。其中一个是，正如manawy所说，我没有一个包装python函数来调用C ++函数。另一个问题是我的C ++文件与.pyx文件同名，因此在编译它时，它会递归地覆盖C ++文件。