Objets Integer

All integers are implemented as "long" integer objects of arbitrary size.

On error, most PyLong_As* APIs return (return type)-1 which cannot be distinguished from a number. Use PyErr_Occurred() to disambiguate.

type PyLongObject
Part of the Limited API (as an opaque struct).

This subtype of PyObject represents a Python integer object.

PyTypeObject PyLong_Type
Part of the Stable ABI.

This instance of PyTypeObject represents the Python integer type. This is the same object as int in the Python layer.

int PyLong_Check(PyObject *p)

Return true if its argument is a PyLongObject or a subtype of PyLongObject. This function always succeeds.

int PyLong_CheckExact(PyObject *p)

Return true if its argument is a PyLongObject, but not a subtype of PyLongObject. This function always succeeds.

PyObject *PyLong_FromLong(long v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from v, or NULL on failure.

The current implementation keeps an array of integer objects for all integers between -5 and 256. When you create an int in that range you actually just get back a reference to the existing object.

PyObject *PyLong_FromUnsignedLong(unsigned long v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from a C unsigned long, or NULL on failure.

PyObject *PyLong_FromSsize_t(Py_ssize_t v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from a C Py_ssize_t, or NULL on failure.

PyObject *PyLong_FromSize_t(size_t v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from a C size_t, or NULL on failure.

PyObject *PyLong_FromLongLong(long long v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from a C long long, or NULL on failure.

PyObject *PyLong_FromUnsignedLongLong(unsigned long long v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from a C unsigned long long, or NULL on failure.

PyObject *PyLong_FromDouble(double v)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject object from the integer part of v, or NULL on failure.

PyObject *PyLong_FromString(const char *str, char **pend, int base)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Return a new PyLongObject based on the string value in str, which is interpreted according to the radix in base, or NULL on failure. If pend is non-NULL, *pend will point to the end of str on success or to the first character that could not be processed on error. If base is 0, str is interpreted using the Entiers littéraux definition; in this case, leading zeros in a non-zero decimal number raises a ValueError. If base is not 0, it must be between 2 and 36, inclusive. Leading and trailing whitespace and single underscores after a base specifier and between digits are ignored. If there are no digits or str is not NULL-terminated following the digits and trailing whitespace, ValueError will be raised.

Voir aussi

Python methods int.to_bytes() and int.from_bytes() to convert a PyLongObject to/from an array of bytes in base 256. You can call those from C using PyObject_CallMethod().

PyObject *PyLong_FromUnicodeObject(PyObject *u, int base)
Valeur de retour : nouvelle référence.

Convert a sequence of Unicode digits in the string u to a Python integer value.

Nouveau dans la version 3.3.

PyObject *PyLong_FromVoidPtr(void *p)
Valeur de retour : nouvelle référence. Part of the Stable ABI.

Create a Python integer from the pointer p. The pointer value can be retrieved from the resulting value using PyLong_AsVoidPtr().

PyObject *PyLong_FromNativeBytes(const void *buffer, size_t n_bytes, int endianness)

Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as a two's-complement signed number.

endianness may be passed -1 for the native endian that CPython was compiled with, or else 0 for big endian and 1 for little.

Nouveau dans la version 3.13.

PyObject *PyLong_FromUnsignedNativeBytes(const void *buffer, size_t n_bytes, int endianness)

Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as an unsigned number.

endianness may be passed -1 for the native endian that CPython was compiled with, or else 0 for big endian and 1 for little.

Nouveau dans la version 3.13.

long PyLong_AsLong(PyObject *obj)
Part of the Stable ABI.

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

int PyLong_AsInt(PyObject *obj)
Part of the Stable ABI since version 3.13.

Similar to PyLong_AsLong(), but store the result in a C int instead of a C long.

Nouveau dans la version 3.13.

long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)
Part of the Stable ABI.

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than LONG_MAX or less than LONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

long long PyLong_AsLongLong(PyObject *obj)
Part of the Stable ABI.

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long long.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)
Part of the Stable ABI.

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than LLONG_MAX or less than LLONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

Nouveau dans la version 3.2.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)
Part of the Stable ABI.

Return a C Py_ssize_t representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a Py_ssize_t.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

unsigned long PyLong_AsUnsignedLong(PyObject *pylong)
Part of the Stable ABI.

Return a C unsigned long representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a unsigned long.

Returns (unsigned long)-1 on error. Use PyErr_Occurred() to disambiguate.

size_t PyLong_AsSize_t(PyObject *pylong)
Part of the Stable ABI.

Return a C size_t representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a size_t.

Returns (size_t)-1 on error. Use PyErr_Occurred() to disambiguate.

unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)
Part of the Stable ABI.

Return a C unsigned long long representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for an unsigned long long.

Returns (unsigned long long)-1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.1: A negative pylong now raises OverflowError, not TypeError.

unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)
Part of the Stable ABI.

Return a C unsigned long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long, return the reduction of that value modulo ULONG_MAX + 1.

Returns (unsigned long)-1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)
Part of the Stable ABI.

Return a C unsigned long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long long, return the reduction of that value modulo ULLONG_MAX + 1.

Returns (unsigned long long)-1 on error. Use PyErr_Occurred() to disambiguate.

Modifié dans la version 3.8: Use __index__() if available.

Modifié dans la version 3.10: This function will no longer use __int__().

double PyLong_AsDouble(PyObject *pylong)
Part of the Stable ABI.

Return a C double representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a double.

Returns -1.0 on error. Use PyErr_Occurred() to disambiguate.

void *PyLong_AsVoidPtr(PyObject *pylong)
Part of the Stable ABI.

Convert a Python integer pylong to a C void pointer. If pylong cannot be converted, an OverflowError will be raised. This is only assured to produce a usable void pointer for values created with PyLong_FromVoidPtr().

Returns NULL on error. Use PyErr_Occurred() to disambiguate.

Py_ssize_t PyLong_AsNativeBytes(PyObject *pylong, void *buffer, Py_ssize_t n_bytes, int endianness)

Copy the Python integer value to a native buffer of size n_bytes:

int32_t value;
Py_ssize_t bytes = PyLong_AsNativeBits(pylong, &value, sizeof(value), -1);
if (bytes < 0) {
    // A Python exception was set with the reason.
    return NULL;
}
else if (bytes <= (Py_ssize_t)sizeof(value)) {
    // Success!
}
else {
    // Overflow occurred, but 'value' contains the truncated
    // lowest bits of pylong.
}

The above example may look similar to PyLong_As* but instead fills in a specific caller defined type and never raises an error about of the int pylong's value regardless of n_bytes or the returned byte count.

To get at the entire potentially big Python value, this can be used to reserve enough space and copy it:

// Ask how much space we need.
Py_ssize_t expected = PyLong_AsNativeBits(pylong, NULL, 0, -1);
if (expected < 0) {
    // A Python exception was set with the reason.
    return NULL;
}
assert(expected != 0);  // Impossible per the API definition.
uint8_t *bignum = malloc(expected);
if (!bignum) {
    PyErr_SetString(PyExc_MemoryError, "bignum malloc failed.");
    return NULL;
}
// Safely get the entire value.
Py_ssize_t bytes = PyLong_AsNativeBits(pylong, bignum, expected, -1);
if (bytes < 0) {  // Exception set.
    free(bignum);
    return NULL;
}
else if (bytes > expected) {  // Be safe, should not be possible.
    PyErr_SetString(PyExc_RuntimeError,
        "Unexpected bignum truncation after a size check.");
    free(bignum);
    return NULL;
}
// The expected success given the above pre-check.
// ... use bignum ...
free(bignum);

endianness may be passed -1 for the native endian that CPython was compiled with, or 0 for big endian and 1 for little.

Returns -1 with an exception raised if pylong cannot be interpreted as an integer. Otherwise, return the size of the buffer required to store the value. If this is equal to or less than n_bytes, the entire value was copied. 0 will never be returned.

Unless an exception is raised, all n_bytes of the buffer will always be written. In the case of truncation, as many of the lowest bits of the value as could fit are written. This allows the caller to ignore all non-negative results if the intent is to match the typical behavior of a C-style downcast. No exception is set on truncation.

Values are always copied as two's-complement and sufficient buffer will be requested to include a sign bit. For example, this may cause an value that fits into 8 bytes when treated as unsigned to request 9 bytes, even though all eight bytes were copied into the buffer. What has been omitted is the zero sign bit -- redundant if the caller's intention is to treat the value as unsigned.

Passing zero to n_bytes will return the size of a buffer that would be large enough to hold the value. This may be larger than technically necessary, but not unreasonably so.

Note

Passing n_bytes=0 to this function is not an accurate way to determine the bit length of a value.

Nouveau dans la version 3.13.

int PyUnstable_Long_IsCompact(const PyLongObject *op)
This is Unstable API. It may change without warning in minor releases.

Return 1 if op is compact, 0 otherwise.

This function makes it possible for performance-critical code to implement a “fast path” for small integers. For compact values use PyUnstable_Long_CompactValue(); for others fall back to a PyLong_As* function or calling int.to_bytes().

The speedup is expected to be negligible for most users.

Exactly what values are considered compact is an implementation detail and is subject to change.

Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject *op)
This is Unstable API. It may change without warning in minor releases.

If op is compact, as determined by PyUnstable_Long_IsCompact(), return its value.

Otherwise, the return value is undefined.