Struct core::num::NonZeroU8

1.28.0 · source ·
#[repr(transparent)]
pub struct NonZeroU8(/* private fields */);
Expand description

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, Option<NonZeroU8> is the same size as u8:

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU8>>(), size_of::<u8>());
Run

Layout

NonZeroU8 is guaranteed to have the same layout and bit validity as u8 with the exception that 0 is not a valid instance. Option<NonZeroU8> is guaranteed to be compatible with u8, including in FFI.

Thanks to the null pointer optimization, NonZeroU8 and Option<NonZeroU8> are guaranteed to have the same size and alignment:

use std::num::NonZeroU8;

assert_eq!(size_of::<NonZeroU8>(), size_of::<Option<NonZeroU8>>());
assert_eq!(align_of::<NonZeroU8>(), align_of::<Option<NonZeroU8>>());
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Implementations§

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impl NonZeroU8

const: 1.28.0 · source

pub const unsafe fn new_unchecked(n: u8) -> Self

Creates a non-zero without checking whether the value is non-zero. This results in undefined behaviour if the value is zero.

Safety

The value must not be zero.

const: 1.47.0 · source

pub const fn new(n: u8) -> Option<Self>

Creates a non-zero if the given value is not zero.

const: 1.34.0 · source

pub const fn get(self) -> u8

Returns the value as a primitive type.

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impl NonZeroU8

1.53.0 (const: 1.53.0) · source

pub const fn leading_zeros(self) -> u32

Returns the number of leading zeros in the binary representation of self.

On many architectures, this function can perform better than leading_zeros() on the underlying integer type, as special handling of zero can be avoided.

Examples

Basic usage:

let n = std::num::NonZeroU8::new(u8::MAX).unwrap();

assert_eq!(n.leading_zeros(), 0);
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1.53.0 (const: 1.53.0) · source

pub const fn trailing_zeros(self) -> u32

Returns the number of trailing zeros in the binary representation of self.

On many architectures, this function can perform better than trailing_zeros() on the underlying integer type, as special handling of zero can be avoided.

Examples

Basic usage:

let n = std::num::NonZeroU8::new(0b0101000).unwrap();

assert_eq!(n.trailing_zeros(), 3);
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impl NonZeroU8

1.64.0 (const: 1.64.0) · source

pub const fn checked_add(self, other: u8) -> Option<NonZeroU8>

Adds an unsigned integer to a non-zero value. Checks for overflow and returns None on overflow. As a consequence, the result cannot wrap to zero.

Examples
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(Some(two), one.checked_add(1));
assert_eq!(None, max.checked_add(1));
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1.64.0 (const: 1.64.0) · source

pub const fn saturating_add(self, other: u8) -> NonZeroU8

Adds an unsigned integer to a non-zero value. Return NonZeroU8::MAX on overflow.

Examples
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(two, one.saturating_add(1));
assert_eq!(max, max.saturating_add(1));
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pub const unsafe fn unchecked_add(self, other: u8) -> NonZeroU8

🔬This is a nightly-only experimental API. (nonzero_ops #84186)

Adds an unsigned integer to a non-zero value, assuming overflow cannot occur. Overflow is unchecked, and it is undefined behaviour to overflow even if the result would wrap to a non-zero value. The behaviour is undefined as soon as self + rhs > u8::MAX.

Examples
#![feature(nonzero_ops)]

let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;

assert_eq!(two, unsafe { one.unchecked_add(1) });
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1.64.0 (const: 1.64.0) · source

pub const fn checked_next_power_of_two(self) -> Option<NonZeroU8>

Returns the smallest power of two greater than or equal to n. Checks for overflow and returns None if the next power of two is greater than the type’s maximum value. As a consequence, the result cannot wrap to zero.

Examples
let two = NonZeroU8::new(2)?;
let three = NonZeroU8::new(3)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(Some(two), two.checked_next_power_of_two() );
assert_eq!(Some(four), three.checked_next_power_of_two() );
assert_eq!(None, max.checked_next_power_of_two() );
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1.67.0 (const: 1.67.0) · source

pub const fn ilog2(self) -> u32

Returns the base 2 logarithm of the number, rounded down.

This is the same operation as u8::ilog2, except that it has no failure cases to worry about since this value can never be zero.

Examples
assert_eq!(NonZeroU8::new(7).unwrap().ilog2(), 2);
assert_eq!(NonZeroU8::new(8).unwrap().ilog2(), 3);
assert_eq!(NonZeroU8::new(9).unwrap().ilog2(), 3);
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1.67.0 (const: 1.67.0) · source

pub const fn ilog10(self) -> u32

Returns the base 10 logarithm of the number, rounded down.

This is the same operation as u8::ilog10, except that it has no failure cases to worry about since this value can never be zero.

Examples
assert_eq!(NonZeroU8::new(99).unwrap().ilog10(), 1);
assert_eq!(NonZeroU8::new(100).unwrap().ilog10(), 2);
assert_eq!(NonZeroU8::new(101).unwrap().ilog10(), 2);
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const: unstable · source

pub fn midpoint(self, rhs: Self) -> Self

🔬This is a nightly-only experimental API. (num_midpoint #110840)

Calculates the middle point of self and rhs.

midpoint(a, b) is (a + b) >> 1 as if it were performed in a sufficiently-large signed integral type. This implies that the result is always rounded towards negative infinity and that no overflow will ever occur.

Examples
#![feature(num_midpoint)]

let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;

assert_eq!(one.midpoint(four), two);
assert_eq!(four.midpoint(one), two);
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impl NonZeroU8

1.64.0 (const: 1.64.0) · source

pub const fn checked_mul(self, other: NonZeroU8) -> Option<NonZeroU8>

Multiplies two non-zero integers together. Checks for overflow and returns None on overflow. As a consequence, the result cannot wrap to zero.

Examples
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(Some(four), two.checked_mul(two));
assert_eq!(None, max.checked_mul(two));
Run
1.64.0 (const: 1.64.0) · source

pub const fn saturating_mul(self, other: NonZeroU8) -> NonZeroU8

Multiplies two non-zero integers together. Return NonZeroU8::MAX on overflow.

Examples
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(four, two.saturating_mul(two));
assert_eq!(max, four.saturating_mul(max));
Run
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pub const unsafe fn unchecked_mul(self, other: NonZeroU8) -> NonZeroU8

🔬This is a nightly-only experimental API. (nonzero_ops #84186)

Multiplies two non-zero integers together, assuming overflow cannot occur. Overflow is unchecked, and it is undefined behaviour to overflow even if the result would wrap to a non-zero value. The behaviour is undefined as soon as self * rhs > u8::MAX.

Examples
#![feature(nonzero_ops)]

let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;

assert_eq!(four, unsafe { two.unchecked_mul(two) });
Run
1.64.0 (const: 1.64.0) · source

pub const fn checked_pow(self, other: u32) -> Option<NonZeroU8>

Raises non-zero value to an integer power. Checks for overflow and returns None on overflow. As a consequence, the result cannot wrap to zero.

Examples
let three = NonZeroU8::new(3)?;
let twenty_seven = NonZeroU8::new(27)?;
let half_max = NonZeroU8::new(u8::MAX / 2)?;

assert_eq!(Some(twenty_seven), three.checked_pow(3));
assert_eq!(None, half_max.checked_pow(3));
Run
1.64.0 (const: 1.64.0) · source

pub const fn saturating_pow(self, other: u32) -> NonZeroU8

Raise non-zero value to an integer power. Return NonZeroU8::MAX on overflow.

Examples
let three = NonZeroU8::new(3)?;
let twenty_seven = NonZeroU8::new(27)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));
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impl NonZeroU8

1.59.0 (const: 1.59.0) · source

pub const fn is_power_of_two(self) -> bool

Returns true if and only if self == (1 << k) for some k.

On many architectures, this function can perform better than is_power_of_two() on the underlying integer type, as special handling of zero can be avoided.

Examples

Basic usage:

let eight = std::num::NonZeroU8::new(8).unwrap();
assert!(eight.is_power_of_two());
let ten = std::num::NonZeroU8::new(10).unwrap();
assert!(!ten.is_power_of_two());
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impl NonZeroU8

1.70.0 · source

pub const MIN: Self = _

The smallest value that can be represented by this non-zero integer type, 1.

Examples
assert_eq!(NonZeroU8::MIN.get(), 1u8);
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1.70.0 · source

pub const MAX: Self = _

The largest value that can be represented by this non-zero integer type, equal to u8::MAX.

Examples
assert_eq!(NonZeroU8::MAX.get(), u8::MAX);
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impl NonZeroU8

1.67.0 · source

pub const BITS: u32 = 8u32

The size of this non-zero integer type in bits.

This value is equal to u8::BITS.

Examples

assert_eq!(NonZeroU8::BITS, u8::BITS);
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Trait Implementations§

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impl Binary for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.
1.45.0 · source§

impl BitOr<NonZeroU8> for NonZeroU8

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type Output = NonZeroU8

The resulting type after applying the | operator.
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fn bitor(self, rhs: Self) -> Self::Output

Performs the | operation. Read more
1.45.0 · source§

impl BitOr<NonZeroU8> for u8

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type Output = NonZeroU8

The resulting type after applying the | operator.
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fn bitor(self, rhs: NonZeroU8) -> Self::Output

Performs the | operation. Read more
1.45.0 · source§

impl BitOr<u8> for NonZeroU8

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type Output = NonZeroU8

The resulting type after applying the | operator.
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fn bitor(self, rhs: u8) -> Self::Output

Performs the | operation. Read more
1.45.0 · source§

impl BitOrAssign<NonZeroU8> for NonZeroU8

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fn bitor_assign(&mut self, rhs: Self)

Performs the |= operation. Read more
1.45.0 · source§

impl BitOrAssign<u8> for NonZeroU8

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fn bitor_assign(&mut self, rhs: u8)

Performs the |= operation. Read more
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impl Clone for NonZeroU8

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fn clone(&self) -> NonZeroU8

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Display for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.51.0 · source§

impl Div<NonZeroU8> for u8

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fn div(self, other: NonZeroU8) -> u8

This operation rounds towards zero, truncating any fractional part of the exact result, and cannot panic.

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type Output = u8

The resulting type after applying the / operator.
1.41.0 · source§

impl From<NonZeroU8> for NonZeroI128

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroI128 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroI16

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroI16 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroI32

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroI32 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroI64

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroI64 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroIsize

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroIsize losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroU128

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroU128 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroU16

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroU16 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroU32

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroU32 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroU64

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroU64 losslessly.

1.41.0 · source§

impl From<NonZeroU8> for NonZeroUsize

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroUsize losslessly.

1.31.0 · source§

impl From<NonZeroU8> for u8

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fn from(nonzero: NonZeroU8) -> Self

Converts a NonZeroU8 into an u8

1.35.0 · source§

impl FromStr for NonZeroU8

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type Err = ParseIntError

The associated error which can be returned from parsing.
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fn from_str(src: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type. Read more
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impl Hash for NonZeroU8

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)where Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl LowerHex for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.
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impl Octal for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.
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impl Ord for NonZeroU8

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fn cmp(&self, other: &NonZeroU8) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl PartialEq<NonZeroU8> for NonZeroU8

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fn eq(&self, other: &NonZeroU8) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialOrd<NonZeroU8> for NonZeroU8

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fn partial_cmp(&self, other: &NonZeroU8) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
1.51.0 · source§

impl Rem<NonZeroU8> for u8

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fn rem(self, other: NonZeroU8) -> u8

This operation satisfies n % d == n - (n / d) * d, and cannot panic.

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type Output = u8

The resulting type after applying the % operator.
1.49.0 · source§

impl TryFrom<NonZeroI128> for NonZeroU8

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fn try_from(value: NonZeroI128) -> Result<Self, Self::Error>

Attempts to convert NonZeroI128 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroI16> for NonZeroU8

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fn try_from(value: NonZeroI16) -> Result<Self, Self::Error>

Attempts to convert NonZeroI16 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroI32> for NonZeroU8

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fn try_from(value: NonZeroI32) -> Result<Self, Self::Error>

Attempts to convert NonZeroI32 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroI64> for NonZeroU8

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fn try_from(value: NonZeroI64) -> Result<Self, Self::Error>

Attempts to convert NonZeroI64 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroI8> for NonZeroU8

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fn try_from(value: NonZeroI8) -> Result<Self, Self::Error>

Attempts to convert NonZeroI8 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroIsize> for NonZeroU8

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fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroU128> for NonZeroU8

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fn try_from(value: NonZeroU128) -> Result<Self, Self::Error>

Attempts to convert NonZeroU128 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroU16> for NonZeroU8

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fn try_from(value: NonZeroU16) -> Result<Self, Self::Error>

Attempts to convert NonZeroU16 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroU32> for NonZeroU8

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fn try_from(value: NonZeroU32) -> Result<Self, Self::Error>

Attempts to convert NonZeroU32 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroU64> for NonZeroU8

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fn try_from(value: NonZeroU64) -> Result<Self, Self::Error>

Attempts to convert NonZeroU64 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroU8> for NonZeroI8

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fn try_from(value: NonZeroU8) -> Result<Self, Self::Error>

Attempts to convert NonZeroU8 to NonZeroI8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.49.0 · source§

impl TryFrom<NonZeroUsize> for NonZeroU8

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fn try_from(value: NonZeroUsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroUsize to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
1.46.0 · source§

impl TryFrom<u8> for NonZeroU8

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fn try_from(value: u8) -> Result<Self, Self::Error>

Attempts to convert u8 to NonZeroU8.

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type Error = TryFromIntError

The type returned in the event of a conversion error.
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impl UpperHex for NonZeroU8

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.
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impl Copy for NonZeroU8

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impl Eq for NonZeroU8

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impl StructuralEq for NonZeroU8

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impl StructuralPartialEq for NonZeroU8

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
This documentation is an old archive. Please see https://rust.docs.kernel.org instead.