Struct std::num::NonZeroUsize

1.28.0 · source ·

#[repr(transparent)]
pub struct NonZeroUsize(_);

Expand description

An integer that is known not to equal zero.

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

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroUsize>>(), size_of::<usize>());

Run

Implementations

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impl NonZeroUsize

const: 1.28.0 · source

pub const unsafe fn new_unchecked(n: usize) -> NonZeroUsize

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: usize) -> Option<NonZeroUsize>

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

const: 1.34.0 · source

pub const fn get(self) -> usize

Returns the value as a primitive type.

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impl NonZeroUsize

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::NonZeroUsize::new(usize::MAX).unwrap();
assert_eq!(n.leading_zeros(), 0);

Run

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::NonZeroUsize::new(0b0101000).unwrap();
assert_eq!(n.trailing_zeros(), 3);

Run

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impl NonZeroUsize

1.64.0 (const: 1.64.0) · source

pub const fn checked_add(self, other: usize) -> Option<NonZeroUsize>

Add an unsigned integer to a non-zero value. Check for overflow and return None on overflow As a consequence, the result cannot wrap to zero.

Examples

let one = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;
let max = NonZeroUsize::new(usize::MAX)?;
assert_eq!(Some(two), one.checked_add(1));
assert_eq!(None, max.checked_add(1));

Run

1.64.0 (const: 1.64.0) · source

pub const fn saturating_add(self, other: usize) -> NonZeroUsize

Add an unsigned integer to a non-zero value. Return usize::MAX on overflow.

Examples

let one = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;
let max = NonZeroUsize::new(usize::MAX)?;
assert_eq!(two, one.saturating_add(1));
assert_eq!(max, max.saturating_add(1));

Run

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pub const unsafe fn unchecked_add(self, other: usize) -> NonZeroUsize

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

Add 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 > usize::MAX.

Examples

#![feature(nonzero_ops)]
let one = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;
assert_eq!(two, unsafe { one.unchecked_add(1) });

Run

1.64.0 (const: 1.64.0) · source

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

Returns the smallest power of two greater than or equal to n. Check for overflow and return 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 = NonZeroUsize::new(2)?;
let three = NonZeroUsize::new(3)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::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() );

Run

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pub const fn log2(self) -> u32

🔬 This is a nightly-only experimental API. (int_log #70887)

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

This is the same operation as usize::log2, except that it has no failure cases to worry about since this value can never be zero.

Examples

#![feature(int_log)]
assert_eq!(NonZeroUsize::new(7).unwrap().log2(), 2);
assert_eq!(NonZeroUsize::new(8).unwrap().log2(), 3);
assert_eq!(NonZeroUsize::new(9).unwrap().log2(), 3);

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pub const fn log10(self) -> u32

🔬 This is a nightly-only experimental API. (int_log #70887)

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

This is the same operation as usize::log10, except that it has no failure cases to worry about since this value can never be zero.

Examples

#![feature(int_log)]
assert_eq!(NonZeroUsize::new(99).unwrap().log10(), 1);
assert_eq!(NonZeroUsize::new(100).unwrap().log10(), 2);
assert_eq!(NonZeroUsize::new(101).unwrap().log10(), 2);

Run

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impl NonZeroUsize

1.64.0 (const: 1.64.0) · source

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

Multiply two non-zero integers together. Check for overflow and return None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let two = NonZeroUsize::new(2)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::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: NonZeroUsize) -> NonZeroUsize

Multiply two non-zero integers together. Return usize::MAX on overflow.

Examples

let two = NonZeroUsize::new(2)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::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: NonZeroUsize) -> NonZeroUsize

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

Multiply 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 > usize::MAX.

Examples

#![feature(nonzero_ops)]
let two = NonZeroUsize::new(2)?;
let four = NonZeroUsize::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<NonZeroUsize>

Raise non-zero value to an integer power. Check for overflow and return None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let three = NonZeroUsize::new(3)?;
let twenty_seven = NonZeroUsize::new(27)?;
let half_max = NonZeroUsize::new(usize::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) -> NonZeroUsize

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

Examples

let three = NonZeroUsize::new(3)?;
let twenty_seven = NonZeroUsize::new(27)?;
let max = NonZeroUsize::new(usize::MAX)?;
assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));

Run

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impl NonZeroUsize

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

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impl NonZeroUsize

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pub const MIN: NonZeroUsize = Self::new(1).unwrap()

🔬 This is a nightly-only experimental API. (nonzero_min_max #89065)

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

Examples

#![feature(nonzero_min_max)]
assert_eq!(NonZeroUsize::MIN.get(), 1usize);

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pub const MAX: NonZeroUsize = Self::new(usize::MAX).unwrap()

🔬 This is a nightly-only experimental API. (nonzero_min_max #89065)

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

Examples

#![feature(nonzero_min_max)]
assert_eq!(NonZeroUsize::MAX.get(), usize::MAX);

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impl NonZeroUsize

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pub const BITS: u32 = 64u32

🔬 This is a nightly-only experimental API. (nonzero_bits #94881)

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

This value is equal to usize::BITS.

Examples

#![feature(nonzero_bits)]
assert_eq!(NonZeroUsize::BITS, usize::BITS);

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Trait Implementations

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impl Binary for NonZeroUsize

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

Formats the value using the given formatter.

1.45.0 (const: unstable) · source

impl BitOr<NonZeroUsize> for NonZeroUsize

type Output = NonZeroUsize

The resulting type after applying the | operator.

const: unstable · source

fn bitor(
self,
rhs: NonZeroUsize
) -> <NonZeroUsize as BitOr<NonZeroUsize>>::Output

Performs the | operation. Read more

1.45.0 (const: unstable) · source

impl BitOr<NonZeroUsize> for usize

type Output = NonZeroUsize

The resulting type after applying the | operator.

const: unstable · source

fn bitor(self, rhs: NonZeroUsize) -> <usize as BitOr<NonZeroUsize>>::Output

Performs the | operation. Read more

1.45.0 (const: unstable) · source

impl BitOr<usize> for NonZeroUsize

type Output = NonZeroUsize

The resulting type after applying the | operator.

const: unstable · source

fn bitor(self, rhs: usize) -> <NonZeroUsize as BitOr<usize>>::Output

Performs the | operation. Read more

1.45.0 (const: unstable) · source

impl BitOrAssign<NonZeroUsize> for NonZeroUsize

const: unstable · source

fn bitor_assign(&mut self, rhs: NonZeroUsize)

Performs the |= operation. Read more

1.45.0 (const: unstable) · source

impl BitOrAssign<usize> for NonZeroUsize

const: unstable · source

fn bitor_assign(&mut self, rhs: usize)

Performs the |= operation. Read more

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impl Clone for NonZeroUsize

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fn clone(&self) -> NonZeroUsize

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 NonZeroUsize

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

Formats the value using the given formatter. Read more

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impl Display for NonZeroUsize

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

Formats the value using the given formatter. Read more

1.51.0 (const: unstable) · source

impl Div<NonZeroUsize> for usize

const: unstable · source

fn div(self, other: NonZeroUsize) -> usize

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

type Output = usize

The resulting type after applying the / operator.

1.41.0 (const: unstable) · source

impl From<NonZeroU16> for NonZeroUsize

const: unstable · source

fn from(small: NonZeroU16) -> NonZeroUsize

Converts NonZeroU16 to NonZeroUsize losslessly.

1.41.0 (const: unstable) · source

impl From<NonZeroU8> for NonZeroUsize

const: unstable · source

fn from(small: NonZeroU8) -> NonZeroUsize

Converts NonZeroU8 to NonZeroUsize losslessly.

1.31.0 (const: unstable) · source

impl From<NonZeroUsize> for usize

const: unstable · source

fn from(nonzero: NonZeroUsize) -> usize

Converts a NonZeroUsize into an usize

1.35.0 · source

impl FromStr for NonZeroUsize

type Err = ParseIntError

The associated error which can be returned from parsing.

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fn from_str(src: &str) -> Result<NonZeroUsize, <NonZeroUsize as FromStr>::Err>

Parses a string s to return a value of this type. Read more

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impl Hash for NonZeroUsize

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

Feeds this value into the given Hasher. Read more

1.3.0 · source

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

Feeds a slice of this type into the given Hasher. Read more

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impl LowerHex for NonZeroUsize

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

Formats the value using the given formatter.

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impl Octal for NonZeroUsize

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

Formats the value using the given formatter.

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impl Ord for NonZeroUsize

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

This method returns an Ordering between self and other. Read more

1.21.0 · source

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

Compares and returns the maximum of two values. Read more

1.21.0 · source

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

Compares and returns the minimum of two values. Read more

1.50.0 · source

fn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,

Restrict a value to a certain interval. Read more

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impl PartialEq<NonZeroUsize> for NonZeroUsize

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

This method tests for self and other values to be equal, and is used by ==. Read more

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

This method tests for !=.

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impl PartialOrd<NonZeroUsize> for NonZeroUsize

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fn partial_cmp(&self, other: &NonZeroUsize) -> 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 (const: unstable) · source

impl Rem<NonZeroUsize> for usize

const: unstable · source

fn rem(self, other: NonZeroUsize) -> usize

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

type Output = usize

The resulting type after applying the % operator.

1.49.0 · source

impl TryFrom<NonZeroI128> for NonZeroUsize

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fn try_from(
value: NonZeroI128
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI128>>::Error>

Attempts to convert NonZeroI128 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroI16> for NonZeroUsize

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fn try_from(
value: NonZeroI16
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI16>>::Error>

Attempts to convert NonZeroI16 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroI32> for NonZeroUsize

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fn try_from(
value: NonZeroI32
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI32>>::Error>

Attempts to convert NonZeroI32 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroI64> for NonZeroUsize

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fn try_from(
value: NonZeroI64
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI64>>::Error>

Attempts to convert NonZeroI64 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroI8> for NonZeroUsize

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fn try_from(
value: NonZeroI8
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI8>>::Error>

Attempts to convert NonZeroI8 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroIsize> for NonZeroUsize

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fn try_from(
value: NonZeroIsize
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroIsize>>::Error>

Attempts to convert NonZeroIsize to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroU128> for NonZeroUsize

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fn try_from(
value: NonZeroU128
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU128>>::Error>

Attempts to convert NonZeroU128 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroU32> for NonZeroUsize

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fn try_from(
value: NonZeroU32
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU32>>::Error>

Attempts to convert NonZeroU32 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroU64> for NonZeroUsize

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fn try_from(
value: NonZeroU64
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU64>>::Error>

Attempts to convert NonZeroU64 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroI128

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroI128, <NonZeroI128 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroI16

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroI16, <NonZeroI16 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroI32

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroI32, <NonZeroI32 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroI64

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroI64, <NonZeroI64 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI64.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroI8

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroI8, <NonZeroI8 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroIsize

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroIsize, <NonZeroIsize as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroU128

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU128, <NonZeroU128 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroU16

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU16, <NonZeroU16 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroU32

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU32, <NonZeroU32 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.49.0 · source

impl TryFrom<NonZeroUsize> for NonZeroU64

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fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU64, <NonZeroU64 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU64.

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<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

1.46.0 · source

impl TryFrom<usize> for NonZeroUsize

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fn try_from(
value: usize
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<usize>>::Error>

Attempts to convert usize to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

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impl UpperHex for NonZeroUsize

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

Formats the value using the given formatter.

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impl Copy for NonZeroUsize

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impl Eq for NonZeroUsize

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impl StructuralEq for NonZeroUsize

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impl StructuralPartialEq for NonZeroUsize