text: #ifndef Py_CPYTHON_ABSTRACTOBJECT_H
  #  error "this header file must not be included directly"
  #endif
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /* === Object Protocol ================================================== */
  
  #ifdef PY_SSIZE_T_CLEAN
  #  define _PyObject_CallMethodId _PyObject_CallMethodId_SizeT
  #endif
  
  /* Convert keyword arguments from the FASTCALL (stack: C array, kwnames: tuple)
     format to a Python dictionary ("kwargs" dict).
  
     The type of kwnames keys is not checked. The final function getting
     arguments is responsible to check if all keys are strings, for example using
     PyArg_ParseTupleAndKeywords() or PyArg_ValidateKeywordArguments().
  
     Duplicate keys are merged using the last value. If duplicate keys must raise
     an exception, the caller is responsible to implement an explicit keys on
     kwnames. */
  PyAPI_FUNC(PyObject *) _PyStack_AsDict(
      PyObject *const *values,
      PyObject *kwnames);
  
  /* Suggested size (number of positional arguments) for arrays of PyObject*
     allocated on a C stack to avoid allocating memory on the heap memory. Such
     array is used to pass positional arguments to call functions of the
     PyObject_Vectorcall() family.
  
     The size is chosen to not abuse the C stack and so limit the risk of stack
     overflow. The size is also chosen to allow using the small stack for most
     function calls of the Python standard library. On 64-bit CPU, it allocates
     40 bytes on the stack. */
  #define _PY_FASTCALL_SMALL_STACK 5
  
  PyAPI_FUNC(PyObject *) _Py_CheckFunctionResult(
      PyThreadState *tstate,
      PyObject *callable,
      PyObject *result,
      const char *where);
  
  /* === Vectorcall protocol (PEP 590) ============================= */
  
  /* Call callable using tp_call. Arguments are like PyObject_Vectorcall()
     or PyObject_FastCallDict() (both forms are supported),
     except that nargs is plainly the number of arguments without flags. */
  PyAPI_FUNC(PyObject *) _PyObject_MakeTpCall(
      PyThreadState *tstate,
      PyObject *callable,
      PyObject *const *args, Py_ssize_t nargs,
      PyObject *keywords);
  
  #define PY_VECTORCALL_ARGUMENTS_OFFSET ((size_t)1 << (8 * sizeof(size_t) - 1))
  
  static inline Py_ssize_t
  PyVectorcall_NARGS(size_t n)
  {
      return n & ~PY_VECTORCALL_ARGUMENTS_OFFSET;
  }
  
  static inline vectorcallfunc
  PyVectorcall_Function(PyObject *callable)
  {
      PyTypeObject *tp;
      Py_ssize_t offset;
      vectorcallfunc ptr;
  
      assert(callable != NULL);
      tp = Py_TYPE(callable);
      if (!PyType_HasFeature(tp, Py_TPFLAGS_HAVE_VECTORCALL)) {
          return NULL;
      }
      assert(PyCallable_Check(callable));
      offset = tp->tp_vectorcall_offset;
      assert(offset > 0);
      memcpy(&ptr, (char *) callable + offset, sizeof(ptr));
      return ptr;
  }
  
  /* Call the callable object 'callable' with the "vectorcall" calling
     convention.
  
     args is a C array for positional arguments.
  
     nargsf is the number of positional arguments plus optionally the flag
     PY_VECTORCALL_ARGUMENTS_OFFSET which means that the caller is allowed to
     modify args[-1].
  
     kwnames is a tuple of keyword names. The values of the keyword arguments
     are stored in "args" after the positional arguments (note that the number
     of keyword arguments does not change nargsf). kwnames can also be NULL if
     there are no keyword arguments.
  
     keywords must only contain strings and all keys must be unique.
  
     Return the result on success. Raise an exception and return NULL on
     error. */
  static inline PyObject *
  _PyObject_VectorcallTstate(PyThreadState *tstate, PyObject *callable,
                             PyObject *const *args, size_t nargsf,
                             PyObject *kwnames)
  {
      vectorcallfunc func;
      PyObject *res;
  
      assert(kwnames == NULL || PyTuple_Check(kwnames));
      assert(args != NULL || PyVectorcall_NARGS(nargsf) == 0);
  
      func = PyVectorcall_Function(callable);
      if (func == NULL) {
          Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
          return _PyObject_MakeTpCall(tstate, callable, args, nargs, kwnames);
      }
      res = func(callable, args, nargsf, kwnames);
      return _Py_CheckFunctionResult(tstate, callable, res, NULL);
  }
  
  static inline PyObject *
  PyObject_Vectorcall(PyObject *callable, PyObject *const *args,
                       size_t nargsf, PyObject *kwnames)
  {
      PyThreadState *tstate = PyThreadState_GET();
      return _PyObject_VectorcallTstate(tstate, callable,
                                        args, nargsf, kwnames);
  }
  
  // Backwards compatibility aliases for API that was provisional in Python 3.8
  #define _PyObject_Vectorcall PyObject_Vectorcall
  #define _PyObject_VectorcallMethod PyObject_VectorcallMethod
  #define _PyObject_FastCallDict PyObject_VectorcallDict
  #define _PyVectorcall_Function PyVectorcall_Function
  #define _PyObject_CallOneArg PyObject_CallOneArg
  #define _PyObject_CallMethodNoArgs PyObject_CallMethodNoArgs
  #define _PyObject_CallMethodOneArg PyObject_CallMethodOneArg
  
  /* Same as PyObject_Vectorcall except that keyword arguments are passed as
     dict, which may be NULL if there are no keyword arguments. */
  PyAPI_FUNC(PyObject *) PyObject_VectorcallDict(
      PyObject *callable,
      PyObject *const *args,
      size_t nargsf,
      PyObject *kwargs);
  
  /* Call "callable" (which must support vectorcall) with positional arguments
     "tuple" and keyword arguments "dict". "dict" may also be NULL */
  PyAPI_FUNC(PyObject *) PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *dict);
  
  static inline PyObject *
  _PyObject_FastCallTstate(PyThreadState *tstate, PyObject *func, PyObject *const *args, Py_ssize_t nargs)
  {
      return _PyObject_VectorcallTstate(tstate, func, args, (size_t)nargs, NULL);
  }
  
  /* Same as PyObject_Vectorcall except without keyword arguments */
  static inline PyObject *
  _PyObject_FastCall(PyObject *func, PyObject *const *args, Py_ssize_t nargs)
  {
      PyThreadState *tstate = PyThreadState_GET();
      return _PyObject_FastCallTstate(tstate, func, args, nargs);
  }
  
  /* Call a callable without any arguments
     Private static inline function variant of public function
     PyObject_CallNoArgs(). */
  static inline PyObject *
  _PyObject_CallNoArg(PyObject *func) {
      PyThreadState *tstate = PyThreadState_GET();
      return _PyObject_VectorcallTstate(tstate, func, NULL, 0, NULL);
  }
  
  static inline PyObject *
  PyObject_CallOneArg(PyObject *func, PyObject *arg)
  {
      PyObject *_args[2];
      PyObject **args;
      PyThreadState *tstate;
      size_t nargsf;
  
      assert(arg != NULL);
      args = _args + 1;  // For PY_VECTORCALL_ARGUMENTS_OFFSET
      args[0] = arg;
      tstate = PyThreadState_GET();
      nargsf = 1 | PY_VECTORCALL_ARGUMENTS_OFFSET;
      return _PyObject_VectorcallTstate(tstate, func, args, nargsf, NULL);
  }
  
  PyAPI_FUNC(PyObject *) PyObject_VectorcallMethod(
      PyObject *name, PyObject *const *args,
      size_t nargsf, PyObject *kwnames);
  
  static inline PyObject *
  PyObject_CallMethodNoArgs(PyObject *self, PyObject *name)
  {
      return PyObject_VectorcallMethod(name, &self,
             1 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
  }
  
  static inline PyObject *
  PyObject_CallMethodOneArg(PyObject *self, PyObject *name, PyObject *arg)
  {
      PyObject *args[2] = {self, arg};
  
      assert(arg != NULL);
      return PyObject_VectorcallMethod(name, args,
             2 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
  }
  
  /* Like PyObject_CallMethod(), but expect a _Py_Identifier*
     as the method name. */
  PyAPI_FUNC(PyObject *) _PyObject_CallMethodId(PyObject *obj,
                                                _Py_Identifier *name,
                                                const char *format, ...);
  
  PyAPI_FUNC(PyObject *) _PyObject_CallMethodId_SizeT(PyObject *obj,
                                                      _Py_Identifier *name,
                                                      const char *format,
                                                      ...);
  
  PyAPI_FUNC(PyObject *) _PyObject_CallMethodIdObjArgs(
      PyObject *obj,
      struct _Py_Identifier *name,
      ...);
  
  static inline PyObject *
  _PyObject_VectorcallMethodId(
      _Py_Identifier *name, PyObject *const *args,
      size_t nargsf, PyObject *kwnames)
  {
      PyObject *oname = _PyUnicode_FromId(name); /* borrowed */
      if (!oname) {
          return NULL;
      }
      return PyObject_VectorcallMethod(oname, args, nargsf, kwnames);
  }
  
  static inline PyObject *
  _PyObject_CallMethodIdNoArgs(PyObject *self, _Py_Identifier *name)
  {
      return _PyObject_VectorcallMethodId(name, &self,
             1 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
  }
  
  static inline PyObject *
  _PyObject_CallMethodIdOneArg(PyObject *self, _Py_Identifier *name, PyObject *arg)
  {
      PyObject *args[2] = {self, arg};
  
      assert(arg != NULL);
      return _PyObject_VectorcallMethodId(name, args,
             2 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
  }
  
  PyAPI_FUNC(int) _PyObject_HasLen(PyObject *o);
  
  /* Guess the size of object 'o' using len(o) or o.__length_hint__().
     If neither of those return a non-negative value, then return the default
     value.  If one of the calls fails, this function returns -1. */
  PyAPI_FUNC(Py_ssize_t) PyObject_LengthHint(PyObject *o, Py_ssize_t);
  
  /* === New Buffer API ============================================ */
  
  /* Return 1 if the getbuffer function is available, otherwise return 0. */
  PyAPI_FUNC(int) PyObject_CheckBuffer(PyObject *obj);
  
  /* This is a C-API version of the getbuffer function call.  It checks
     to make sure object has the required function pointer and issues the
     call.
  
     Returns -1 and raises an error on failure and returns 0 on success. */
  PyAPI_FUNC(int) PyObject_GetBuffer(PyObject *obj, Py_buffer *view,
                                     int flags);
  
  /* Get the memory area pointed to by the indices for the buffer given.
     Note that view->ndim is the assumed size of indices. */
  PyAPI_FUNC(void *) PyBuffer_GetPointer(Py_buffer *view, Py_ssize_t *indices);
  
  /* Return the implied itemsize of the data-format area from a
     struct-style description. */
  PyAPI_FUNC(Py_ssize_t) PyBuffer_SizeFromFormat(const char *format);
  
  /* Implementation in memoryobject.c */
  PyAPI_FUNC(int) PyBuffer_ToContiguous(void *buf, Py_buffer *view,
                                        Py_ssize_t len, char order);
  
  PyAPI_FUNC(int) PyBuffer_FromContiguous(Py_buffer *view, void *buf,
                                          Py_ssize_t len, char order);
  
  /* Copy len bytes of data from the contiguous chunk of memory
     pointed to by buf into the buffer exported by obj.  Return
     0 on success and return -1 and raise a PyBuffer_Error on
     error (i.e. the object does not have a buffer interface or
     it is not working).
  
     If fort is 'F', then if the object is multi-dimensional,
     then the data will be copied into the array in
     Fortran-style (first dimension varies the fastest).  If
     fort is 'C', then the data will be copied into the array
     in C-style (last dimension varies the fastest).  If fort
     is 'A', then it does not matter and the copy will be made
     in whatever way is more efficient. */
  PyAPI_FUNC(int) PyObject_CopyData(PyObject *dest, PyObject *src);
  
  /* Copy the data from the src buffer to the buffer of destination. */
  PyAPI_FUNC(int) PyBuffer_IsContiguous(const Py_buffer *view, char fort);
  
  /*Fill the strides array with byte-strides of a contiguous
    (Fortran-style if fort is 'F' or C-style otherwise)
    array of the given shape with the given number of bytes
    per element. */
  PyAPI_FUNC(void) PyBuffer_FillContiguousStrides(int ndims,
                                                 Py_ssize_t *shape,
                                                 Py_ssize_t *strides,
                                                 int itemsize,
                                                 char fort);
  
  /* Fills in a buffer-info structure correctly for an exporter
     that can only share a contiguous chunk of memory of
     "unsigned bytes" of the given length.
  
     Returns 0 on success and -1 (with raising an error) on error. */
  PyAPI_FUNC(int) PyBuffer_FillInfo(Py_buffer *view, PyObject *o, void *buf,
                                    Py_ssize_t len, int readonly,
                                    int flags);
  
  /* Releases a Py_buffer obtained from getbuffer ParseTuple's "s*". */
  PyAPI_FUNC(void) PyBuffer_Release(Py_buffer *view);
  
  /* ==== Iterators ================================================ */
  
  #define PyIter_Check(obj) \
      (Py_TYPE(obj)->tp_iternext != NULL && \
       Py_TYPE(obj)->tp_iternext != &_PyObject_NextNotImplemented)
  
  /* === Sequence protocol ================================================ */
  
  /* Assume tp_as_sequence and sq_item exist and that 'i' does not
     need to be corrected for a negative index. */
  #define PySequence_ITEM(o, i)\
      ( Py_TYPE(o)->tp_as_sequence->sq_item(o, i) )
  
  #define PY_ITERSEARCH_COUNT    1
  #define PY_ITERSEARCH_INDEX    2
  #define PY_ITERSEARCH_CONTAINS 3
  
  /* Iterate over seq.
  
     Result depends on the operation:
  
     PY_ITERSEARCH_COUNT:  return # of times obj appears in seq; -1 if
       error.
     PY_ITERSEARCH_INDEX:  return 0-based index of first occurrence of
       obj in seq; set ValueError and return -1 if none found;
       also return -1 on error.
     PY_ITERSEARCH_CONTAINS:  return 1 if obj in seq, else 0; -1 on
       error. */
  PyAPI_FUNC(Py_ssize_t) _PySequence_IterSearch(PyObject *seq,
                                                PyObject *obj, int operation);
  
  /* === Mapping protocol ================================================= */
  
  PyAPI_FUNC(int) _PyObject_RealIsInstance(PyObject *inst, PyObject *cls);
  
  PyAPI_FUNC(int) _PyObject_RealIsSubclass(PyObject *derived, PyObject *cls);
  
  PyAPI_FUNC(char *const *) _PySequence_BytesToCharpArray(PyObject* self);
  
  PyAPI_FUNC(void) _Py_FreeCharPArray(char *const array[]);
  
  /* For internal use by buffer API functions */
  PyAPI_FUNC(void) _Py_add_one_to_index_F(int nd, Py_ssize_t *index,
                                          const Py_ssize_t *shape);
  PyAPI_FUNC(void) _Py_add_one_to_index_C(int nd, Py_ssize_t *index,
                                          const Py_ssize_t *shape);
  
  /* Convert Python int to Py_ssize_t. Do nothing if the argument is None. */
  PyAPI_FUNC(int) _Py_convert_optional_to_ssize_t(PyObject *, void *);
  
  #ifdef __cplusplus
  }
  #endif
  