pyport.h

#ifndef Py_PYPORT_H
#define Py_PYPORT_H

#include "pyconfig.h" /* include for defines */

#include <inttypes.h>

#include <limits.h>
#ifndef UCHAR_MAX
#  error "limits.h must define UCHAR_MAX"
#endif
#if UCHAR_MAX != 255
#  error "Python's source code assumes C's unsigned char is an 8-bit type"
#endif


// Macro to use C++ static_cast<>, reinterpret_cast<> and const_cast<>
// in the Python C API.
//
// In C++, _Py_CAST(type, expr) converts a constant expression to a
// non constant type using const_cast<type>. For example,
// _Py_CAST(PyObject*, op) can convert a "const PyObject*" to
// "PyObject*".
//
// The type argument must not be a constant type.
#ifdef __cplusplus
#  define _Py_STATIC_CAST(type, expr) static_cast<type>(expr)
extern "C++" {
    namespace {
        template <typename type, typename expr_type>
            inline type _Py_CAST_impl(expr_type *expr) {
                return reinterpret_cast<type>(expr);
            }

        template <typename type, typename expr_type>
            inline type _Py_CAST_impl(expr_type const *expr) {
                return reinterpret_cast<type>(const_cast<expr_type *>(expr));
            }

        template <typename type, typename expr_type>
            inline type _Py_CAST_impl(expr_type &expr) {
                return static_cast<type>(expr);
            }

        template <typename type, typename expr_type>
            inline type _Py_CAST_impl(expr_type const &expr) {
                return static_cast<type>(const_cast<expr_type &>(expr));
            }
    }
}
#  define _Py_CAST(type, expr) _Py_CAST_impl<type>(expr)

#else
#  define _Py_STATIC_CAST(type, expr) ((type)(expr))
#  define _Py_CAST(type, expr) ((type)(expr))
#endif

// Static inline functions should use _Py_NULL rather than using directly NULL
// to prevent C++ compiler warnings. In C++, _Py_NULL uses nullptr.
#ifdef __cplusplus
#  define _Py_NULL nullptr
#else
#  define _Py_NULL NULL
#endif


/* Defines to build Python and its standard library:
 *
 * - Py_BUILD_CORE: Build Python core. Give access to Python internals, but
 *   should not be used by third-party modules.