Extensions for Python

备注：这里是我为培训写的PPT，网上资料较少，特此分享出来。

  

What is python extension?

    The extension of python is that provided by other computer language such as C/C++.

    Creating extensions for python involves three main steps:

      1. Creating application code

      2. Wrapping code with boilerplates

      3. Compilation and testing

 

      1. Creating application code

         To call c function in python, we need program codes inherit corresponding wrap’s interface,and then Complier them as a python’s module.

 

      2. Wrapping code with boilerplates

      1). Include Python header file

          #include “python.h”/< python.h >

      2). Add PyObject* Module_func() Python wrappers for each  module function

          PyObject* method(PyObject* self, PyObject* args);

      3). Add PyMethodDef ModuleMethods[] array/table for each  module function

      4). Add void initModule() module initialize function

 

      3.Complier And Test

          Python was default built with visual studio 2003. if you compile in dos, available compiler as follows:

          

         

        1). create the setup.py file

            from distutils.core import setup, Extension

            MOD = ‘ModuleName‘

            setup(name=MOD, ext_modules=[ Extension(MOD,  sources=[‘C++fileName'])])

        2). run “setup.py build” in commandline

  

        3).copy the pyd file from “../Python25/build/lib.win32-2.5” folder to” ../Python25/DLLs” folder then we can import the extension in python.

        4).Import And Test

        

A simple example for python extensions.

 

   setp1: open Lcc-win32，choose file/new/file, create file type as follows:

        

    Click ok button.

 

Create hello.c script, save this file.

#include <python.h>

#include <string.h>

static PyObject *message(PyObject *self, PyObject *args)

{

    char *fromPython, result[64];

    if (!PyArg_Parse(args, "(s)", &fromPython))

        return NULL;

    else

     {

        strcpy(result, "Hello, ");

        strcat(result, fromPython);

        return Py_BuildValue("s", result);

    }

}

static  PyMethodDef

helloMethods[] =

{

        {"message", message, 1},

        {NULL, NULL},

};

void inithello()

{

    Py_InitModule("hello", helloMethods);

}

        2.Copy hello.c file to python root directory. For example: “C:/Python25”

        3. Create a setup.py file in “C:/Python25”.

            from distutils.core import setup, Extension

            MOD = 'hello'

            setup(name=MOD, ext_modules=[

            Extension(MOD, sources=['hello.c'])])

         4. Open your windows shell window,entry into your python root, then input this command as follows:

 

        

         5).copy the pyd file from “../Python25/build/lib.win32-2.5” folder to” ../Python25/DLLs” folder then we can import the extension in python.

        

         6).Import And Test

           

        

          Now, Import successfully!