Type Alias core::num::NonZeroIsize

1.34.0 · source ·
pub type NonZeroIsize = NonZero<isize>;
Expand description

An integer that is known not to equal zero.

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

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroIsize>>(), size_of::<isize>());
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§Layout

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

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

use std::num::NonZeroIsize;

assert_eq!(size_of::<NonZeroIsize>(), size_of::<Option<NonZeroIsize>>());
assert_eq!(align_of::<NonZeroIsize>(), align_of::<Option<NonZeroIsize>>());
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Aliased Type§

struct NonZeroIsize(/* private fields */);

Implementations§

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impl NonZeroIsize

const: 1.34.0 · source

pub const unsafe fn new_unchecked(n: isize) -> 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: isize) -> Option<Self>

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

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pub unsafe fn from_mut_unchecked(n: &mut isize) -> &mut Self

🔬This is a nightly-only experimental API. (nonzero_from_mut #106290)

Converts a primitive mutable reference to a non-zero mutable reference without checking whether the referenced value is non-zero. This results in undefined behavior if *n is zero.

§Safety

The referenced value must not be currently zero.

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pub fn from_mut(n: &mut isize) -> Option<&mut Self>

🔬This is a nightly-only experimental API. (nonzero_from_mut #106290)

Converts a primitive mutable reference to a non-zero mutable reference if the referenced integer is not zero.

const: 1.34.0 · source

pub const fn get(self) -> isize

Returns the value as a primitive type.

1.67.0 · source

pub const BITS: u32 = 64u32

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

This value is equal to isize::BITS.

§Examples

assert_eq!(NonZeroIsize::BITS, isize::BITS);
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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::NonZeroIsize::new(-1isize).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::NonZeroIsize::new(0b0101000).unwrap();

assert_eq!(n.trailing_zeros(), 3);
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const: unstable · source

pub fn count_ones(self) -> NonZeroU32

🔬This is a nightly-only experimental API. (non_zero_count_ones #120287)

Returns the number of ones in the binary representation of self.

§Examples

Basic usage:

#![feature(non_zero_count_ones)]

let one = num::NonZeroU32::new(1)?;
let three = num::NonZeroU32::new(3)?;
let a = NonZeroIsize::new(0b100_0000)?;
let b = NonZeroIsize::new(0b100_0011)?;

assert_eq!(a.count_ones(), one);
assert_eq!(b.count_ones(), three);
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1.70.0 · source

pub const MIN: Self = _

The smallest value that can be represented by this non-zero integer type, equal to isize::MIN.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

§Examples
assert_eq!(NonZeroIsize::MIN.get(), isize::MIN);
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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 isize::MAX.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

§Examples
assert_eq!(NonZeroIsize::MAX.get(), isize::MAX);
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1.64.0 (const: 1.64.0) · source

pub const fn abs(self) -> Self

Computes the absolute value of self. See isize::abs for documentation on overflow behaviour.

§Example
let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;

assert_eq!(pos, pos.abs());
assert_eq!(pos, neg.abs());
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1.64.0 (const: 1.64.0) · source

pub const fn checked_abs(self) -> Option<Self>

Checked absolute value. Checks for overflow and returns None if self == NonZeroIsize::MIN. The result cannot be zero.

§Example
let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(Some(pos), neg.checked_abs());
assert_eq!(None, min.checked_abs());
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1.64.0 (const: 1.64.0) · source

pub const fn overflowing_abs(self) -> (Self, bool)

Computes the absolute value of self, with overflow information, see isize::overflowing_abs.

§Example
let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!((pos, false), pos.overflowing_abs());
assert_eq!((pos, false), neg.overflowing_abs());
assert_eq!((min, true), min.overflowing_abs());
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1.64.0 (const: 1.64.0) · source

pub const fn saturating_abs(self) -> Self

Saturating absolute value, see isize::saturating_abs.

§Example
let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;
let min_plus = NonZeroIsize::new(isize::MIN + 1)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos, pos.saturating_abs());
assert_eq!(pos, neg.saturating_abs());
assert_eq!(max, min.saturating_abs());
assert_eq!(max, min_plus.saturating_abs());
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1.64.0 (const: 1.64.0) · source

pub const fn wrapping_abs(self) -> Self

Wrapping absolute value, see isize::wrapping_abs.

§Example
let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos, pos.wrapping_abs());
assert_eq!(pos, neg.wrapping_abs());
assert_eq!(min, min.wrapping_abs());
assert_eq!(max, (-max).wrapping_abs());
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1.64.0 (const: 1.64.0) · source

pub const fn unsigned_abs(self) -> NonZeroUsize

Computes the absolute value of self without any wrapping or panicking.

§Example

let u_pos = NonZeroUsize::new(1)?;
let i_pos = NonZeroIsize::new(1)?;
let i_neg = NonZeroIsize::new(-1)?;
let i_min = NonZeroIsize::new(isize::MIN)?;
let u_max = NonZeroUsize::new(usize::MAX / 2 + 1)?;

assert_eq!(u_pos, i_pos.unsigned_abs());
assert_eq!(u_pos, i_neg.unsigned_abs());
assert_eq!(u_max, i_min.unsigned_abs());
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1.71.0 (const: 1.71.0) · source

pub const fn is_positive(self) -> bool

Returns true if self is positive and false if the number is negative.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;

assert!(pos_five.is_positive());
assert!(!neg_five.is_positive());
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1.71.0 (const: 1.71.0) · source

pub const fn is_negative(self) -> bool

Returns true if self is negative and false if the number is positive.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;

assert!(neg_five.is_negative());
assert!(!pos_five.is_negative());
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1.71.0 (const: 1.71.0) · source

pub const fn checked_neg(self) -> Option<Self>

Checked negation. Computes -self, returning None if self == NonZeroIsize::MIN.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.checked_neg(), Some(neg_five));
assert_eq!(min.checked_neg(), None);
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1.71.0 (const: 1.71.0) · source

pub const fn overflowing_neg(self) -> (Self, bool)

Negates self, overflowing if this is equal to the minimum value.

See isize::overflowing_neg for documentation on overflow behaviour.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.overflowing_neg(), (neg_five, false));
assert_eq!(min.overflowing_neg(), (min, true));
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1.71.0 (const: 1.71.0) · source

pub const fn saturating_neg(self) -> Self

Saturating negation. Computes -self, returning NonZeroIsize::MAX if self == NonZeroIsize::MIN instead of overflowing.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;
let min_plus_one = NonZeroIsize::new(isize::MIN + 1)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos_five.saturating_neg(), neg_five);
assert_eq!(min.saturating_neg(), max);
assert_eq!(max.saturating_neg(), min_plus_one);
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1.71.0 (const: 1.71.0) · source

pub const fn wrapping_neg(self) -> Self

Wrapping (modular) negation. Computes -self, wrapping around at the boundary of the type.

See isize::wrapping_neg for documentation on overflow behaviour.

§Example
let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.wrapping_neg(), neg_five);
assert_eq!(min.wrapping_neg(), min);
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1.64.0 (const: 1.64.0) · source

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

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 = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

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

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

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

§Examples
let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(four, two.saturating_mul(two));
assert_eq!(max, four.saturating_mul(max));
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source

pub const unsafe fn unchecked_mul(self, other: Self) -> Self

🔬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 > isize::MAX, or self * rhs < isize::MIN.

§Examples
#![feature(nonzero_ops)]

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

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

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

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 = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let half_max = NonZeroIsize::new(isize::MAX / 2)?;

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

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

Raise non-zero value to an integer power. Return NonZeroIsize::MIN or NonZeroIsize::MAX on overflow.

§Examples
let three = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));
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Trait Implementations§

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impl Binary for NonZeroIsize

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

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

impl BitOr<isize> for NonZeroIsize

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type Output = NonZero<isize>

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

Performs the | operation. Read more
1.45.0 · source§

impl BitOr for NonZeroIsize

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type Output = NonZero<isize>

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 BitOrAssign<isize> for NonZeroIsize

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fn bitor_assign(&mut self, rhs: isize)

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

impl BitOrAssign for NonZeroIsize

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fn bitor_assign(&mut self, rhs: Self)

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

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fn clone(&self) -> Self

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 NonZeroIsize

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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 NonZeroIsize

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

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

impl From<NonZero<i16>> for NonZeroIsize

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fn from(small: NonZeroI16) -> Self

Converts NonZeroI16 to NonZeroIsize losslessly.

1.41.0 · source§

impl From<NonZero<i8>> for NonZeroIsize

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fn from(small: NonZeroI8) -> Self

Converts NonZeroI8 to NonZeroIsize losslessly.

1.41.0 · source§

impl From<NonZero<u8>> for NonZeroIsize

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fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroIsize losslessly.

1.35.0 · source§

impl FromStr for NonZeroIsize

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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 NonZeroIsize

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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: 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 NonZeroIsize

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

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

impl Neg for &NonZeroIsize

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type Output = <NonZero<isize> as Neg>::Output

The resulting type after applying the - operator.
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fn neg(self) -> <NonZeroIsize as Neg>::Output

Performs the unary - operation. Read more
1.71.0 · source§

impl Neg for NonZeroIsize

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type Output = NonZero<isize>

The resulting type after applying the - operator.
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fn neg(self) -> Self

Performs the unary - operation. Read more
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impl Octal for NonZeroIsize

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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 NonZeroIsize

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

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval. Read more
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impl PartialEq for NonZeroIsize

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Self) -> 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 for NonZeroIsize

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

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Self) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Self) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Self) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Self) -> bool

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

impl TryFrom<NonZero<i128>> for NonZeroIsize

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

Attempts to convert NonZeroI128 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<i32>> for NonZeroIsize

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

Attempts to convert NonZeroI32 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<i64>> for NonZeroIsize

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

Attempts to convert NonZeroI64 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<u128>> for NonZeroIsize

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

Attempts to convert NonZeroU128 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<u16>> for NonZeroIsize

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

Attempts to convert NonZeroU16 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<u32>> for NonZeroIsize

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

Attempts to convert NonZeroU32 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<u64>> for NonZeroIsize

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

Attempts to convert NonZeroU64 to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<NonZero<usize>> for NonZeroIsize

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

Attempts to convert NonZeroUsize to NonZeroIsize.

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type Error = TryFromIntError

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

impl TryFrom<isize> for NonZeroIsize

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

Attempts to convert isize to NonZeroIsize.

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type Error = TryFromIntError

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

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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 NonZeroIsize

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impl Eq for NonZeroIsize

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impl StructuralPartialEq for NonZeroIsize