foo.cc

#include <Python.h>
#include <stddef.h>

#ifndef MODULE_NAME
#define MODULE_NAME ext_typical
#endif

// Stringification requires two levels of indirection (_STR and _XSTR) because
// #s will not expand argment s.  Instead, macro expansion occurs when _XSTR
// is expanded, then the result of this expansion is stringified in _STR.
#define _STR(s) #s
#define _XSTR(s) _STR(s)
#define _MODULE_STRING _XSTR(MODULE_NAME)

// Token concatenation requires two levels of indirection (similar to
// stringification).
#define _CONCAT(x, y) x##y
#define _XCONCAT(x, y) _CONCAT(x, y)
#define _INIT_FUNC_NAME _XCONCAT(PyInit_, MODULE_NAME)

struct module_state {
  //PyObject *error;
};

extern "C" {

static PyMethodDef ext_simple_symbols[] = {
    {nullptr, nullptr}  // sentinel
};

static int ext_simple_traverse(PyObject *m, visitproc visit, void *arg) {
  return 0;
}

static int ext_simple_clear(PyObject *m) {
  return 0;
}

static struct PyModuleDef moduledef = {
    PyModuleDef_HEAD_INIT,       _MODULE_STRING,     nullptr,
    sizeof(struct module_state), ext_simple_symbols, nullptr,
    ext_simple_traverse,         ext_simple_clear,   nullptr};

PyMODINIT_FUNC _INIT_FUNC_NAME(void) {
  PyObject *module = PyModule_Create(&moduledef);

  if (module == nullptr) {
    return nullptr;
  }
  return module;
}
}