# Number Protocol¶

int PyNumber_Check(PyObject *o)
Part of the Stable ABI.

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

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)

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)

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)

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

PyObject *PyNumber_FloorDivide(PyObject *o1, PyObject *o2)

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 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)

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)

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)

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)

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)

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

PyObject *PyNumber_Absolute(PyObject *o)

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)

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)

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)

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)

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)

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)

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

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)

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)

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)

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`.

PyObject *PyNumber_InPlaceFloorDivide(PyObject *o1, PyObject *o2)

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 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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)
Part of the Stable ABI.

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)
Part of the Stable ABI since version 3.8.

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.