I tried Python C extension

I copied the first half of the tutorial extension of Python with C and C ++. I was thinking of studying Cython, but I happened to see a blog post about the above method, so I felt like trying it. I have the impression that it will not be that difficult. I don't know the API or anything yet. .. Really squeeze spammodule.c as a tutorial. Paste the comments as they are in the tutorial text.

`spammodule.c`


#include <Python.h>

static PyObject *
spam_system(PyObject *self, PyObject *args)
{
  const char *command;
  int sts;

  if (!PyArg_ParseTuple(args, "s", &command))
    /*A Python string or Unicode object that points to a character string
Convert to C pointer. "s"Meaning of
    */
      return NULL;

  sts = system(command);
  return Py_BuildValue("i", sts);
  /*A new Python object that takes a formatted string and any number of C values as arguments
return it. "i"Means an integer object*/
}

static PyMethodDef SpamMethods[] = {
  {"system", spam_system, METH_VARARGS,
   "Description Execute a shell command."},
  {NULL, NULL, 0, NULL}
};


PyMODINIT_FUNC
initspam(void)
{
  (void) Py_InitModule("spam", SpamMethods);
}

After writing safely, create setup.py as follows. I referred to this article .

`setup.py`



from distutils.core import setup, Extension

module1 = Extension('spam',
                    sources = ['spammodule.c'])

setup (name = 'Spam',
       version = '1.0',
       description = 'This is a spam package',
       ext_modules = [module1])

The rest is on the command line

$python setup.py build

(This time it's an experiment, so I won't install it) To execute. Then, a directory called build will be created directly under the current. I think that the contents differ depending on the environment, but if you specify the path of spam.so and import it It seems that it can be used. I copied and pasted spam.so into a suitable directory (Is it okay?) It was a suitable memo.