编译器找不到Py_InitModule()..是否已弃用，如果可以，我应该使用什么? [英] Compiler can't find Py_InitModule() .. is it deprecated and if so what should I use?

问题描述

我正在尝试为python编写C扩展名.通过下面的代码，我得到了编译器警告:

I am attempting to write a C extension for python. With the code (below) I get the compiler warning:

implicit declaration of function ‘Py_InitModule’

它在运行时由于以下错误而失败:

And it fails at run time with this error:

undefined symbol: Py_InitModule

我花了数小时来寻找解决方案，但并没有感到高兴.我尝试对语法进行多次细微更改，甚至发现一则帖子表明该方法已被弃用.但是我找不到替代品.

I have spent literally hours searching for a solution with no joy. I have tried multiple minor changes to syntax, I even found a post suggesting the method has been deprecated. However I find no replacement.

这是代码:

#include <Python.h>

//a func to calc fib numbers
int cFib(int n)
{
    if (n<2) return n;
    return cFib(n-1) + cFib(n-2);
}


static PyObject* fib(PyObject* self,PyObject* args)
{
    int n;
    if (!PyArg_ParseTuple(args,"i",&n)) 
        return NULL;    
    return Py_BuildValue("i",cFib(n));
}

static PyMethodDef module_methods[] = {
    {"fib",(PyCFunction) fib, METH_VARARGS,"calculates the fibonachi number"},
    {NULL,NULL,0,NULL}
};

PyMODINIT_FUNC initcModPyDem(void)
{
    Py_InitModule("cModPyDem",module_methods,"a module");
}

如果有帮助，这里是我的setup.py:

If it helps here is my setup.py :

from distutils.core import setup, Extension

module = Extension('cModPyDem', sources=['cModPyDem.c'])
setup(name = 'packagename', 
    version='1.0',
    description = 'a test package',
    ext_modules = [module])

还有test.py中的测试代码:

And the test code in test.py :

import cModPyDem

if __name__ == '__main__' :

    print(cModPyDem.fib(200))

任何帮助将不胜感激.

推荐答案

您拥有的代码在Python 2.x中可以正常工作，但是Py_InitModule在Python 3.x中不再使用.如今，您创建了一个 PyModuleDef 结构，然后将对其传递引用到 PyModule_Create .

The code you have would work fine in Python 2.x, but Py_InitModule is no longer used in Python 3.x. Nowadays, you create a PyModuleDef structure and then pass a reference to it to PyModule_Create.

结构如下:

static struct PyModuleDef cModPyDem =
{
    PyModuleDef_HEAD_INIT,
    "cModPyDem", /* name of module */
    "",          /* module documentation, may be NULL */
    -1,          /* size of per-interpreter state of the module, or -1 if the module keeps state in global variables. */
    module_methods
};

然后您的PyMODINIT_FUNC函数如下所示:

And then your PyMODINIT_FUNC function would look like:

PyMODINIT_FUNC PyInit_cModPyDem(void)
{
    return PyModule_Create(&cModPyDem);
}

请注意，PyMODINIT_FUNC函数的名称必须采用PyInit_<name>的形式，其中<name>是模块的名称.

Note that the name of the PyMODINIT_FUNC function must be of the form PyInit_<name> where <name> is the name of your module.

如果您阅读Python 3.x文档中的扩展，我认为这是值得的.它详细介绍了如何在现代Python中构建扩展模块.

I think it would be worthwhile if you read Extending in the Python 3.x documentation. It has a detailed description of how to build extension modules in modern Python.

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