include/python3.9/cpython/interpreteridobject.h

#ifndef Py_CPYTHON_INTERPRETERIDOBJECT_H
#  error "this header file must not be included directly"
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* Interpreter ID Object */

PyAPI_DATA(PyTypeObject) _PyInterpreterID_Type;

PyAPI_FUNC(PyObject *) _PyInterpreterID_New(int64_t);
PyAPI_FUNC(PyObject *) _PyInterpreterState_GetIDObject(PyInterpreterState *);
PyAPI_FUNC(PyInterpreterState *) _PyInterpreterID_LookUp(PyObject *);

#ifdef __cplusplus
}
#endif