用C语言实现python的扩展模块
示例1：
1    Example.c
int add(int a,int b)
{
        return a+b;
}

int sub(int a,int b)
{
        return a -b;
}

int mul(int a,int b)
{
        return a*b;
}

int div1(int a,int b)
{
        if(0 == b)
        {
                return b;
        }
        return a/b;
}
2  wrap.c
#include <Python.h> //python.h中已经包含了常用的头文件
PyObject* wrap_add(PyObject* self, PyObject* args)
{
  int n1,n2, result;
 
  if (! PyArg_ParseTuple(args, "i|i", &n1,&n2))
    return NULL;
  result = add(n1,n2);
  return Py_BuildValue("i", result);
}

PyObject* wrap_sub(PyObject* self, PyObject* args)
{
  int n1,n2, result;
 
  if (! PyArg_ParseTuple(args, "i|i", &n1,&n2))
    return NULL;
  result = sub(n1,n2);
  return Py_BuildValue("i", result);
}

PyObject* wrap_mul(PyObject* self, PyObject* args)
{
  int n1,n2, result;
 
  if (! PyArg_ParseTuple(args, "i|i", &n1,&n2))
    return NULL;
  result = mul(n1,n2);
  return Py_BuildValue("i", result);
}
PyObject* wrap_div1(PyObject* self, PyObject* args)
{
  int n1,n2, result;
  if (! PyArg_ParseTuple(args, "i|i", &n1,&n2))
    return NULL;
  result = div1(n1,n2);
  return Py_BuildValue("i", result);
}


static PyMethodDef exampleMethods[] =
{
  {"add", wrap_add, METH_VARARGS, "Caculate 1!"},
  {"sub", wrap_sub, METH_VARARGS, "Caculate 2!"},
  {"mul", wrap_mul, METH_VARARGS, "Caculate 3!"},
  {"div1", wrap_div1, METH_VARARGS, "Caculate 4!"},
  {NULL, NULL,0,NULL}
};

void initexample()
{
  PyObject* m;
  m = Py_InitModule("example", exampleMethods);
}
3 编译
gcc -fpic -c -I /usr/include/python2.6/ -I /usr/lib/python2.6/config example.c wrap.c
gcc -shared -o wrap.so  wrap.o
4 功能演示截图
 
5  主要参考：
5．1    Python的C语言扩展
http://www.ibm.com/developerworks/cn/linux/l-pythc/
5．2  浅谈 Python 程序和 C 程序的整合
http://www.ibm.com/developerworks/cn/linux/l-cn-pythonandc/index.html?ca=drs-cn-0506

示例2：（支持回调python中定义的函数）
1  mytest.c
#include <Python.h>
static PyObject *my_callback = NULL;
static PyObject* my_strlen(PyObject *self, PyObject *args)
{
   char *string;
   int len;
   if (!PyArg_ParseTuple(args, "s", &string))

     return NULL;
   len = strlen(string);
   return Py_BuildValue("i", len);
}

static PyObject* my_strcat(PyObject *self, PyObject *args)
{
    char* string1;
    char* string2;
    char* newstring;

    if (!PyArg_ParseTuple(args, "s|s", &string1, &string2))
        return NULL;
    newstring = strcat(string1, string2);
    return Py_BuildValue("s", newstring);
}

static PyObject* my_set_callback(PyObject *self, PyObject *args)
{
    PyObject *result = NULL;
    PyObject *temp;

    if (PyArg_ParseTuple(args, "O", &temp))
    {
         if (!PyCallable_Check(temp))
        {
              PyErr_SetString(PyExc_TypeError, "parameter must be callable");
              return NULL;
         }
     Py_XINCREF(temp);
     Py_XDECREF(my_callback);
     my_callback = temp;

     Py_INCREF(Py_None);
     result = Py_None;
   }
   return result;
}
static PyObject* my_test_callback(PyObject *self, PyObject *args)
{
    PyObject * arglist;
    PyObject * result = NULL;

    result = PyEval_CallObject(my_callback, args);
    if (result == NULL)
    {
        return NULL;
    }
    Py_DECREF(result);
    Py_INCREF(Py_None);
    return Py_None;
}

static PyMethodDef mytestMethods[] =
{
     {"mystrlen", my_strlen, METH_VARARGS, "We test strlen of C"},
     {"mystrcat", my_strcat, METH_VARARGS, "We test strcat of C"},
     {"mysetcallback", my_set_callback, METH_VARARGS, "we set a call back function so that call it in C"},
     {"mytestcallback", my_test_callback, METH_VARARGS, "we use this function to test call back function"},
     {NULL, NULL, 0, NULL}
};

void initmytest()
{
      (void) Py_InitModule("mytest", mytestMethods);
}
2  编译
gcc -fpic -c -I /usr/include/python2.6/ -I /usr/lib/python2.6/config   mytest.c
gcc -shared -o mytest.so  mytest.o
3 功能演示截图
 
4 主要参考
4.1 . Calling Python Functions from C
4.2 在windows上扩展python
http://blog.chinaunix.net/space.php?uid=46552&do=blog&id=2116527
4.3 [精华] 在windows上扩展python(2)--从c中调用python函数
http://www.linuxforum.net/forum/gshowthreaded.php?Cat=&Board=python&Number=485550&page=3&view=collapsed&sb=5&o=all&vc=1