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.
This subtype of PyObject represents a Python integer object.
This instance of PyTypeObject represents the Python integer type.
This is the same object as int in the Python layer.
Return true if its argument is a PyLongObject or a subtype of
PyLongObject. This function always succeeds.
Return true if its argument is a PyLongObject, but not a subtype of
PyLongObject. This function always succeeds.
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.
Return a new PyLongObject object from a C unsigned long, or
NULL on failure.
Return a new PyLongObject object from a C Py_ssize_t, or
NULL on failure.
Return a new PyLongObject object from a C size_t, or
NULL on failure.
Return a new PyLongObject object from a C long long, or NULL
on failure.
Return a new PyLongObject object from a C unsigned long long,
or NULL on failure.
Return a new PyLongObject object from the integer part of v, or
NULL on failure.
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 Integer literals 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.
也參考
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().
Convert a sequence of Unicode digits in the string u to a Python integer value.
在 3.3 版被加入.
Create a Python integer from the pointer p. The pointer value can be
retrieved from the resulting value using PyLong_AsVoidPtr().
Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as a two's-complement signed number.
flags are as for PyLong_AsNativeBytes(). Passing -1 will select
the native endian that CPython was compiled with and assume that the
most-significant bit is a sign bit. Passing
Py_ASNATIVEBYTES_UNSIGNED_BUFFER will produce the same result as calling
PyLong_FromUnsignedNativeBytes(). Other flags are ignored.
在 3.13 版被加入.
Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as an unsigned number.
flags are as for PyLong_AsNativeBytes(). Passing -1 will select
the native endian that CPython was compiled with and assume that the
most-significant bit is not a sign bit. Flags other than endian are ignored.
在 3.13 版被加入.
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.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
A soft deprecated alias.
Exactly equivalent to the preferred PyLong_AsLong. In particular,
it can fail with OverflowError or another exception.
在 3.14 版之後被棄用: The function is soft deprecated.
Similar to PyLong_AsLong(), but store the result in a C
int instead of a C long.
在 3.13 版被加入.
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.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
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.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
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.
在 3.2 版被加入.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
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.
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.
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.
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.
在 3.1 版的變更: A negative pylong now raises OverflowError, not TypeError.
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.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
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.
在 3.8 版的變更: Use __index__() if available.
在 3.10 版的變更: This function will no longer use __int__().
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.
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.
Copy the Python integer value pylong to a native buffer of size
n_bytes. The flags can be set to -1 to behave similarly to a C cast,
or to values documented below to control the behavior.
Returns -1 with an exception raised on error. This may happen if
pylong cannot be interpreted as an integer, or if pylong was negative
and the Py_ASNATIVEBYTES_REJECT_NEGATIVE flag was set.
Otherwise, returns the number of bytes required to store the value. If this is equal to or less than n_bytes, the entire value was copied. All n_bytes of the buffer are written: large buffers are padded with zeroes.
If the returned value is greater than than n_bytes, the value was truncated: as many of the lowest bits of the value as could fit are written, and the higher bits are ignored. This matches the typical behavior of a C-style downcast.
備註
Overflow is not considered an error. If the returned value is larger than n_bytes, most significant bits were discarded.
0 將永不被回傳。
Values are always copied as two's-complement.
使用範例：
int32_t value;
Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, &value, sizeof(value), -1);
if (bytes < 0) {
// Failed. 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.
}
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. If n_bytes=0, buffer may be
NULL.
備註
Passing n_bytes=0 to this function is not an accurate way to determine the bit length of the value.
To get at the entire Python value of an unknown size, the function can be called twice: first to determine the buffer size, then to fill it:
// Ask how much space we need.
Py_ssize_t expected = PyLong_AsNativeBytes(pylong, NULL, 0, -1);
if (expected < 0) {
// Failed. 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_AsNativeBytes(pylong, bignum, expected, -1);
if (bytes < 0) { // Exception has been set.
free(bignum);
return NULL;
}
else if (bytes > expected) { // This 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);
flags is either -1 (Py_ASNATIVEBYTES_DEFAULTS) to select defaults
that behave most like a C cast, or a combination of the other flags in
the table below.
Note that -1 cannot be combined with other flags.
Currently, -1 corresponds to
Py_ASNATIVEBYTES_NATIVE_ENDIAN | Py_ASNATIVEBYTES_UNSIGNED_BUFFER.
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Specifying Py_ASNATIVEBYTES_NATIVE_ENDIAN will override any other endian
flags. Passing 2 is reserved.
By default, sufficient buffer will be requested to include a sign bit. For example, when converting 128 with n_bytes=1, the function will return 2 (or more) in order to store a zero sign bit.
If Py_ASNATIVEBYTES_UNSIGNED_BUFFER is specified, a zero sign bit
will be omitted from size calculations. This allows, for example, 128 to fit
in a single-byte buffer. If the destination buffer is later treated as
signed, a positive input value may become negative.
Note that the flag does not affect handling of negative values: for those,
space for a sign bit is always requested.
Specifying Py_ASNATIVEBYTES_REJECT_NEGATIVE causes an exception to be set
if pylong is negative. Without this flag, negative values will be copied
provided there is enough space for at least one sign bit, regardless of
whether Py_ASNATIVEBYTES_UNSIGNED_BUFFER was specified.
If Py_ASNATIVEBYTES_ALLOW_INDEX is specified and a non-integer value is
passed, its __index__() method will be called first. This may
result in Python code executing and other threads being allowed to run, which
could cause changes to other objects or values in use. When flags is
-1, this option is not set, and non-integer values will raise
TypeError.
備註
With the default flags (-1, or UNSIGNED_BUFFER without
REJECT_NEGATIVE), multiple Python integers can map to a single value
without overflow. For example, both 255 and -1 fit a single-byte
buffer and set all its bits.
This matches typical C cast behavior.
在 3.13 版被加入.
On success, return a read only named tuple, that holds
information about Python's internal representation of integers.
See sys.int_info for description of individual fields.
在失敗時，會回傳 NULL 並設定例外。
在 3.1 版被加入.
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
PyLong_AsNativeBytes().
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.
在 3.12 版被加入.
If op is compact, as determined by PyUnstable_Long_IsCompact(),
return its value.
Otherwise, the return value is undefined.
在 3.12 版被加入.