# Primitive Type u641.0.0[−]

## Expand description

The 64-bit unsigned integer type.

## Implementations

Converts a string slice in a given base to an integer.

The string is expected to be an optional `+`

sign
followed by digits.
Leading and trailing whitespace represent an error.
Digits are a subset of these characters, depending on `radix`

:

`0-9`

`a-z`

`A-Z`

# Panics

This function panics if `radix`

is not in the range from 2 to 36.

# Examples

Basic usage:

assert_eq!(u64::from_str_radix("A", 16), Ok(10));Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rotate_left(self, n: u32) -> u64`

1.0.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rotate_left(self, n: u32) -> u64`

1.0.0 (const: 1.32.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rotate_right(self, n: u32) -> u64`

1.0.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rotate_right(self, n: u32) -> u64`

1.0.0 (const: 1.32.0)[src]Shifts the bits to the right by a specified amount, `n`

,
wrapping the truncated bits to the beginning of the resulting
integer.

Please note this isn’t the same operation as the `>>`

shifting operator!

# Examples

Basic usage:

let n = 0x6e10aau64; let m = 0xaa00000000006e1; assert_eq!(n.rotate_right(12), m);Run

Reverses the order of bits in the integer. The least significant bit becomes the most significant bit, second least-significant bit becomes second most-significant bit, etc.

# Examples

Basic usage:

let n = 0x1234567890123456u64; let m = n.reverse_bits(); assert_eq!(m, 0x6a2c48091e6a2c48); assert_eq!(0, 0u64.reverse_bits());Run

Converts an integer from little endian to the target’s endianness.

On little endian this is a no-op. On big endian the bytes are swapped.

# Examples

Basic usage:

let n = 0x1Au64; if cfg!(target_endian = "little") { assert_eq!(u64::from_le(n), n) } else { assert_eq!(u64::from_le(n), n.swap_bytes()) }Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_add(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_add(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_add(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_add(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer addition. Computes `self + rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self + rhs > u64::MAX`

or `self + rhs < u64::MIN`

,
i.e. when `checked_add`

would return `None`

.

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_sub(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_sub(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_sub(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_sub(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer subtraction. Computes `self - rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self - rhs > u64::MAX`

or `self - rhs < u64::MIN`

,
i.e. when `checked_sub`

would return `None`

.

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_mul(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_mul(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_mul(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_mul(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer multiplication. Computes `self * rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self * rhs > u64::MAX`

or `self * rhs < u64::MIN`

,
i.e. when `checked_mul`

would return `None`

.

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_div(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_div(self, rhs: u64) -> Option<u64>`

1.0.0 (const: 1.52.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_div_euclid(self, rhs: u64) -> Option<u64>`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_div_euclid(self, rhs: u64) -> Option<u64>`

1.38.0 (const: 1.52.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_rem(self, rhs: u64) -> Option<u64>`

1.7.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_rem(self, rhs: u64) -> Option<u64>`

1.7.0 (const: 1.52.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_rem_euclid(self, rhs: u64) -> Option<u64>`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_rem_euclid(self, rhs: u64) -> Option<u64>`

1.38.0 (const: 1.52.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_shl(self, rhs: u32) -> Option<u64>`

1.7.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_shl(self, rhs: u32) -> Option<u64>`

1.7.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_shl(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_shl(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift left. Computes `self << rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

# Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shl`

would return `None`

.

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_shr(self, rhs: u32) -> Option<u64>`

1.7.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_shr(self, rhs: u32) -> Option<u64>`

1.7.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_shr(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const unsafe fn unchecked_shr(self, rhs: u64) -> u64`

[src]## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift right. Computes `self >> rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

# Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shr`

would return `None`

.

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_pow(self, exp: u32) -> Option<u64>`

1.34.0 (const: 1.50.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn checked_pow(self, exp: u32) -> Option<u64>`

1.34.0 (const: 1.50.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_add(self, rhs: u64) -> u64`

1.0.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_add(self, rhs: u64) -> u64`

1.0.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_sub(self, rhs: u64) -> u64`

1.0.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_sub(self, rhs: u64) -> u64`

1.0.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_mul(self, rhs: u64) -> u64`

1.7.0 (const: 1.47.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_mul(self, rhs: u64) -> u64`

1.7.0 (const: 1.47.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_pow(self, exp: u32) -> u64`

1.34.0 (const: 1.50.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn saturating_pow(self, exp: u32) -> u64`

1.34.0 (const: 1.50.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_add(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_add(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_sub(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_sub(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_mul(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_mul(self, rhs: u64) -> u64`

1.0.0 (const: 1.32.0)[src]Wrapping (modular) multiplication. Computes `self * rhs`

, wrapping around at the boundary of the type.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u8`

is used here.

assert_eq!(10u8.wrapping_mul(12), 120); assert_eq!(25u8.wrapping_mul(12), 44);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_div(self, rhs: u64) -> u64`

1.2.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_div(self, rhs: u64) -> u64`

1.2.0 (const: 1.52.0)[src]Wrapping (modular) division. Computes `self / rhs`

.
Wrapped division on unsigned types is just normal division.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.

# Examples

Basic usage:

assert_eq!(100u64.wrapping_div(10), 10);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_div_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_div_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]Wrapping Euclidean division. Computes `self.div_euclid(rhs)`

.
Wrapped division on unsigned types is just normal division.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.wrapping_div(rhs)`

.

# Examples

Basic usage:

assert_eq!(100u64.wrapping_div_euclid(10), 10);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_rem(self, rhs: u64) -> u64`

1.2.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_rem(self, rhs: u64) -> u64`

1.2.0 (const: 1.52.0)[src]Wrapping (modular) remainder. Computes `self % rhs`

.
Wrapped remainder calculation on unsigned types is
just the regular remainder calculation.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.

# Examples

Basic usage:

assert_eq!(100u64.wrapping_rem(10), 0);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_rem_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_rem_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`

.
Wrapped modulo calculation on unsigned types is
just the regular remainder calculation.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.wrapping_rem(rhs)`

.

# Examples

Basic usage:

assert_eq!(100u64.wrapping_rem_euclid(10), 0);Run

Wrapping (modular) negation. Computes `-self`

,
wrapping around at the boundary of the type.

Since unsigned types do not have negative equivalents
all applications of this function will wrap (except for `-0`

).
For values smaller than the corresponding signed type’s maximum
the result is the same as casting the corresponding signed value.
Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)`

where
`MAX`

is the corresponding signed type’s maximum.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `i8`

is used here.

assert_eq!(100i8.wrapping_neg(), -100); assert_eq!((-128i8).wrapping_neg(), -128);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_shl(self, rhs: u32) -> u64`

1.2.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_shl(self, rhs: u32) -> u64`

1.2.0 (const: 1.32.0)[src]Panic-free bitwise shift-left; yields `self << mask(rhs)`

,
where `mask`

removes any high-order bits of `rhs`

that
would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-left; the
RHS of a wrapping shift-left is restricted to the range
of the type, rather than the bits shifted out of the LHS
being returned to the other end. The primitive integer
types all implement a `rotate_left`

function,
which may be what you want instead.

# Examples

Basic usage:

assert_eq!(1u64.wrapping_shl(7), 128); assert_eq!(1u64.wrapping_shl(128), 1);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_shr(self, rhs: u32) -> u64`

1.2.0 (const: 1.32.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_shr(self, rhs: u32) -> u64`

1.2.0 (const: 1.32.0)[src]Panic-free bitwise shift-right; yields `self >> mask(rhs)`

,
where `mask`

removes any high-order bits of `rhs`

that
would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-right; the
RHS of a wrapping shift-right is restricted to the range
of the type, rather than the bits shifted out of the LHS
being returned to the other end. The primitive integer
types all implement a `rotate_right`

function,
which may be what you want instead.

# Examples

Basic usage:

assert_eq!(128u64.wrapping_shr(7), 1); assert_eq!(128u64.wrapping_shr(128), 128);Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_pow(self, exp: u32) -> u64`

1.34.0 (const: 1.50.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn wrapping_pow(self, exp: u32) -> u64`

1.34.0 (const: 1.50.0)[src]Calculates `self`

+ `rhs`

Returns a tuple of the addition along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage

assert_eq!(5u64.overflowing_add(2), (7, false)); assert_eq!(u64::MAX.overflowing_add(1), (0, true));Run

Calculates `self`

- `rhs`

Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage

assert_eq!(5u64.overflowing_sub(2), (3, false)); assert_eq!(0u64.overflowing_sub(1), (u64::MAX, true));Run

Calculates the multiplication of `self`

and `rhs`

.

Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u32`

is used here.

assert_eq!(5u32.overflowing_mul(2), (10, false)); assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));Run

Calculates the divisor when `self`

is divided by `rhs`

.

Returns a tuple of the divisor along with a boolean indicating
whether an arithmetic overflow would occur. Note that for unsigned
integers overflow never occurs, so the second value is always
`false`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

assert_eq!(5u64.overflowing_div(2), (2, false));Run

Calculates the quotient of Euclidean division `self.div_euclid(rhs)`

.

Returns a tuple of the divisor along with a boolean indicating
whether an arithmetic overflow would occur. Note that for unsigned
integers overflow never occurs, so the second value is always
`false`

.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.overflowing_div(rhs)`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

assert_eq!(5u64.overflowing_div_euclid(2), (2, false));Run

Calculates the remainder when `self`

is divided by `rhs`

.

Returns a tuple of the remainder after dividing along with a boolean
indicating whether an arithmetic overflow would occur. Note that for
unsigned integers overflow never occurs, so the second value is
always `false`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

assert_eq!(5u64.overflowing_rem(2), (1, false));Run

Calculates the remainder `self.rem_euclid(rhs)`

as if by Euclidean division.

Returns a tuple of the modulo after dividing along with a boolean
indicating whether an arithmetic overflow would occur. Note that for
unsigned integers overflow never occurs, so the second value is
always `false`

.
Since, for the positive integers, all common
definitions of division are equal, this operation
is exactly equal to `self.overflowing_rem(rhs)`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

assert_eq!(5u64.overflowing_rem_euclid(2), (1, false));Run

Negates self in an overflowing fashion.

Returns `!self + 1`

using wrapping operations to return the value
that represents the negation of this unsigned value. Note that for
positive unsigned values overflow always occurs, but negating 0 does
not overflow.

# Examples

Basic usage

assert_eq!(0u64.overflowing_neg(), (0, false)); assert_eq!(2u64.overflowing_neg(), (-2i32 as u64, true));Run

Shifts self left by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

# Examples

Basic usage

assert_eq!(0x1u64.overflowing_shl(4), (0x10, false)); assert_eq!(0x1u64.overflowing_shl(132), (0x10, true));Run

Shifts self right by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

# Examples

Basic usage

assert_eq!(0x10u64.overflowing_shr(4), (0x1, false)); assert_eq!(0x10u64.overflowing_shr(132), (0x1, true));Run

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn div_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn div_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rem_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]

`#[must_use = "this returns the result of the operation, \ without modifying the original"]pub const fn rem_euclid(self, rhs: u64) -> u64`

1.38.0 (const: 1.52.0)[src]Calculates the least remainder of `self (mod rhs)`

.

Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self % rhs`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage:

assert_eq!(7u64.rem_euclid(4), 3); // or any other integer typeRun

Returns the smallest power of two greater than or equal to `self`

.

When return value overflows (i.e., `self > (1 << (N-1))`

for type
`uN`

), it panics in debug mode and return value is wrapped to 0 in
release mode (the only situation in which method can return 0).

# Examples

Basic usage:

assert_eq!(2u64.next_power_of_two(), 2); assert_eq!(3u64.next_power_of_two(), 4);Run

Returns the smallest power of two greater than or equal to `n`

. If
the next power of two is greater than the type’s maximum value,
`None`

is returned, otherwise the power of two is wrapped in `Some`

.

# Examples

Basic usage:

assert_eq!(2u64.checked_next_power_of_two(), Some(2)); assert_eq!(3u64.checked_next_power_of_two(), Some(4)); assert_eq!(u64::MAX.checked_next_power_of_two(), None);Run

## 🔬 This is a nightly-only experimental API. (`wrapping_next_power_of_two`

#32463)

needs decision on wrapping behaviour

## 🔬 This is a nightly-only experimental API. (`wrapping_next_power_of_two`

#32463)

needs decision on wrapping behaviour

Returns the smallest power of two greater than or equal to `n`

. If
the next power of two is greater than the type’s maximum value,
the return value is wrapped to `0`

.

# Examples

Basic usage:

#![feature(wrapping_next_power_of_two)] assert_eq!(2u64.wrapping_next_power_of_two(), 2); assert_eq!(3u64.wrapping_next_power_of_two(), 4); assert_eq!(u64::MAX.wrapping_next_power_of_two(), 0);Run

Return the memory representation of this integer as a byte array in native byte order.

As the target platform’s native endianness is used, portable code
should use `to_be_bytes`

or `to_le_bytes`

, as appropriate,
instead.

# Examples

let bytes = 0x1234567890123456u64.to_ne_bytes(); assert_eq!( bytes, if cfg!(target_endian = "big") { [0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56] } else { [0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12] } );Run

Create a native endian integer value from its representation as a byte array in big endian.

# Examples

let value = u64::from_be_bytes([0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]); assert_eq!(value, 0x1234567890123456);Run

When starting from a slice rather than an array, fallible conversion APIs can be used:

use std::convert::TryInto; fn read_be_u64(input: &mut &[u8]) -> u64 { let (int_bytes, rest) = input.split_at(std::mem::size_of::<u64>()); *input = rest; u64::from_be_bytes(int_bytes.try_into().unwrap()) }Run

Create a native endian integer value from its representation as a byte array in little endian.

# Examples

let value = u64::from_le_bytes([0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]); assert_eq!(value, 0x1234567890123456);Run

When starting from a slice rather than an array, fallible conversion APIs can be used:

use std::convert::TryInto; fn read_le_u64(input: &mut &[u8]) -> u64 { let (int_bytes, rest) = input.split_at(std::mem::size_of::<u64>()); *input = rest; u64::from_le_bytes(int_bytes.try_into().unwrap()) }Run

Create a native endian integer value from its memory representation as a byte array in native endianness.

As the target platform’s native endianness is used, portable code
likely wants to use `from_be_bytes`

or `from_le_bytes`

, as
appropriate instead.

# Examples

let value = u64::from_ne_bytes(if cfg!(target_endian = "big") { [0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56] } else { [0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12] }); assert_eq!(value, 0x1234567890123456);Run

When starting from a slice rather than an array, fallible conversion APIs can be used:

use std::convert::TryInto; fn read_ne_u64(input: &mut &[u8]) -> u64 { let (int_bytes, rest) = input.split_at(std::mem::size_of::<u64>()); *input = rest; u64::from_ne_bytes(int_bytes.try_into().unwrap()) }Run

## 👎 Deprecating in a future Rust version: replaced by the `MIN`

associated constant on this type

replaced by the `MIN`

associated constant on this type

New code should prefer to use
`u64::MIN`

instead.

Returns the smallest value that can be represented by this integer type.

## Trait Implementations

Performs the `+=`

operation. Read more

Performs the `+=`

operation. Read more

Performs the `&=`

operation. Read more

Performs the `&=`

operation. Read more

`type Output = NonZeroU64`

`type Output = NonZeroU64`

The resulting type after applying the `|`

operator.

Performs the `|`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `^=`

operation. Read more

Performs the `^=`

operation. Read more

This operation rounds towards zero, truncating any fractional part of the exact result.

# Panics

This operation will panic if `other == 0`

.

Performs the `/=`

operation. Read more

Performs the `/=`

operation. Read more

Converts a `NonZeroU64`

into an `u64`

`type Err = ParseIntError`

`type Err = ParseIntError`

The associated error which can be returned from parsing.

Performs the `*=`

operation. Read more

Performs the `*=`

operation. Read more

This method returns an ordering between `self`

and `other`

values if one exists. Read more

This method tests less than (for `self`

and `other`

) and is used by the `<`

operator. Read more

This method tests less than or equal to (for `self`

and `other`

) and is used by the `<=`

operator. Read more

This method tests greater than or equal to (for `self`

and `other`

) and is used by the `>=`

operator. Read more

This operation satisfies `n % d == n - (n / d) * d`

. The
result has the same sign as the left operand.

# Panics

This operation will panic if `other == 0`

.

Performs the `%=`

operation. Read more

Performs the `%=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the number of *successor* steps required to get from `start`

to `end`

. Read more

Performs the `-=`

operation. Read more

Performs the `-=`

operation. Read more

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

`type Error = TryFromIntError`

`type Error = TryFromIntError`

The type returned in the event of a conversion error.

## Auto Trait Implementations

`impl RefUnwindSafe for u64`

`impl UnwindSafe for u64`

## Blanket Implementations

Mutably borrows from an owned value. Read more