# Number Protocol

int `PyNumber_Check`(PyObject *o)

  Returns `1` if the object o provides numeric protocols, and false otherwise. This function always succeeds.

  Changed in version 3.8: Returns `1` if o is an index integer.

PyObject* `PyNumber_Add`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of adding o1 and o2, or `NULL` on failure. This is the equivalent of the Python expression `o1 + o2`.

PyObject* `PyNumber_Subtract`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of subtracting o2 from o1, or `NULL` on failure. This is the equivalent of the Python expression `o1 - o2`.

PyObject* `PyNumber_Multiply`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of multiplying o1 and o2, or `NULL` on failure. This is the equivalent of the Python expression `o1 * o2`.

PyObject* `PyNumber_MatrixMultiply`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of matrix multiplication on o1 and o2, or `NULL` on failure. This is the equivalent of the Python expression `o1 @ o2`.

  New in version 3.5.

PyObject* `PyNumber_FloorDivide`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Return the floor of o1 divided by o2, or `NULL` on failure. This is the equivalent of the Python expression `o1 // o2`.

PyObject* `PyNumber_TrueDivide`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Return a reasonable approximation for the mathematical value of o1 divided by o2, or `NULL` on failure. The return value is “approximate” because binary floating point numbers are approximate; it is not possible to represent all real numbers in base two. This function can return a floating point value when passed two integers. This is the equivalent of the Python expression `o1 / o2`.

PyObject* `PyNumber_Remainder`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the remainder of dividing o1 by o2, or `NULL` on failure. This is the equivalent of the Python expression `o1 % o2`.

PyObject* `PyNumber_Divmod`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  See the built-in function `divmod()`. Returns `NULL` on failure. This is the equivalent of the Python expression `divmod(o1, o2)`.

PyObject* `PyNumber_Power`(PyObject *o1, PyObject *o2, PyObject *o3)
  Return value: New reference.

  See the built-in function `pow()`. Returns `NULL` on failure. This is the equivalent of the Python expression `pow(o1, o2, o3)`, where o3 is optional. If o3 is to be ignored, pass `Py_None` in its place (passing `NULL` for o3 would cause an illegal memory access).

PyObject* `PyNumber_Negative`(PyObject *o)
  Return value: New reference.

  Returns the negation of o on success, or `NULL` on failure. This is the equivalent of the Python expression `-o`.

PyObject* `PyNumber_Positive`(PyObject *o)
  Return value: New reference.

  Returns o on success, or `NULL` on failure. This is the equivalent of the Python expression `+o`.

PyObject* `PyNumber_Absolute`(PyObject *o)
  Return value: New reference.

  Returns the absolute value of o, or `NULL` on failure. This is the equivalent of the Python expression `abs(o)`.

PyObject* `PyNumber_Invert`(PyObject *o)
  Return value: New reference.

  Returns the bitwise negation of o on success, or `NULL` on failure. This is the equivalent of the Python expression `~o`.

PyObject* `PyNumber_Lshift`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of left shifting o1 by o2 on success, or `NULL` on failure. This is the equivalent of the Python expression `o1 << o2`.

PyObject* `PyNumber_Rshift`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of right shifting o1 by o2 on success, or `NULL` on failure. This is the equivalent of the Python expression `o1 >> o2`.

PyObject* `PyNumber_And`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise and” of o1 and o2 on success and `NULL` on failure. This is the equivalent of the Python expression `o1 & o2`.

PyObject* `PyNumber_Xor`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise exclusive or” of o1 by o2 on success, or `NULL` on failure. This is the equivalent of the Python expression `o1 ^ o2`.

PyObject* `PyNumber_Or`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise or” of o1 and o2 on success, or `NULL` on failure. This is the equivalent of the Python expression `o1 | o2`.

PyObject* `PyNumber_InPlaceAdd`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of adding o1 and o2, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 += o2`.

PyObject* `PyNumber_InPlaceSubtract`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of subtracting o2 from o1, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 -= o2`.

PyObject* `PyNumber_InPlaceMultiply`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of multiplying o1 and o2, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 *= o2`.

PyObject* `PyNumber_InPlaceMatrixMultiply`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of matrix multiplication on o1 and o2, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 @= o2`.

  New in version 3.5.

PyObject* `PyNumber_InPlaceFloorDivide`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the mathematical floor of dividing o1 by o2, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 //= o2`.

PyObject* `PyNumber_InPlaceTrueDivide`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Return a reasonable approximation for the mathematical value of o1 divided by o2, or `NULL` on failure. The return value is “approximate” because binary floating point numbers are approximate; it is not possible to represent all real numbers in base two. This function can return a floating point value when passed two integers. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 /= o2`.

PyObject* `PyNumber_InPlaceRemainder`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the remainder of dividing o1 by o2, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 %= o2`.

PyObject* `PyNumber_InPlacePower`(PyObject *o1, PyObject *o2, PyObject *o3)
  Return value: New reference.

  See the built-in function `pow()`. Returns `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 **= o2` when o3 is `Py_None`, or an in-place variant of `pow(o1, o2, o3)` otherwise. If o3 is to be ignored, pass `Py_None` in its place (passing `NULL` for o3 would cause an illegal memory access).

PyObject* `PyNumber_InPlaceLshift`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of left shifting o1 by o2 on success, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 <<= o2`.

PyObject* `PyNumber_InPlaceRshift`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the result of right shifting o1 by o2 on success, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 >>= o2`.

PyObject* `PyNumber_InPlaceAnd`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise and” of o1 and o2 on success and `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 &= o2`.

PyObject* `PyNumber_InPlaceXor`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise exclusive or” of o1 by o2 on success, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 ^= o2`.

PyObject* `PyNumber_InPlaceOr`(PyObject *o1, PyObject *o2)
  Return value: New reference.

  Returns the “bitwise or” of o1 and o2 on success, or `NULL` on failure. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement `o1 |= o2`.

PyObject* `PyNumber_Long`(PyObject *o)
  Return value: New reference.

  Returns the o converted to an integer object on success, or `NULL` on failure. This is the equivalent of the Python expression `int(o)`.

PyObject* `PyNumber_Float`(PyObject *o)
  Return value: New reference.

  Returns the o converted to a float object on success, or `NULL` on failure. This is the equivalent of the Python expression `float(o)`.

PyObject* `PyNumber_Index`(PyObject *o)
  Return value: New reference.

  Returns the o converted to a Python int on success or `NULL` with a `TypeError` exception raised on failure.

PyObject* `PyNumber_ToBase`(PyObject *n, int base)
  Return value: New reference.

  Returns the integer n converted to base base as a string. The base argument must be one of 2, 8, 10, or 16. For base 2, 8, or 16, the returned string is prefixed with a base marker of `'0b'`, `'0o'`, or `'0x'`, respectively. If n is not a Python int, it is converted with `PyNumber_Index()` first.

Py_ssize_t `PyNumber_AsSsize_t`(PyObject *o, PyObject *exc)

  Returns o converted to a `Py_ssize_t` value if o can be interpreted as an integer. If the call fails, an exception is raised and `-1` is returned.

  If o can be converted to a Python int but the attempt to convert to a `Py_ssize_t` value would raise an `OverflowError`, then the exc argument is the type of exception that will be raised (usually `IndexError` or `OverflowError`). If exc is `NULL`, then the exception is cleared and the value is clipped to `PY_SSIZE_T_MIN` for a negative integer or `PY_SSIZE_T_MAX` for a positive integer.

int `PyIndex_Check`(PyObject *o)

  Returns `1` if o is an index integer (has the `nb_index` slot of the `tp_as_number` structure filled in), and `0` otherwise. This function always succeeds.