NonZeroU32 in core::num - Rust
Description: An integer that is known not to equal zero.

# Struct core::num::NonZeroU32

1.28.0 · source ·

    pub struct NonZeroU32(/* private fields */);

Expand description

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, `Option<NonZeroU32>` is the same size as `u32`:

    use std::mem::size_of;
    assert_eq!(size_of::<Option<core::num::NonZeroU32>>(), size_of::<u32>());

Run

## Layout

`NonZeroU32` is guaranteed to have the same layout and bit validity as `u32` with the exception that `0` is not a valid instance. `Option<NonZeroU32>` is guaranteed to be compatible with `u32`, including in FFI.

Thanks to the null pointer optimization, `NonZeroU32` and `Option<NonZeroU32>` are guaranteed to have the same size and alignment:

    use std::num::NonZeroU32;

    assert_eq!(size_of::<NonZeroU32>(), size_of::<Option<NonZeroU32>>());
    assert_eq!(align_of::<NonZeroU32>(), align_of::<Option<NonZeroU32>>());

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## Implementations§

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### impl NonZeroU32

const: 1.28.0 · source

#### pub const unsafe fn new_unchecked(n: u32) -> 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: u32) -> Option<Self>

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

const: 1.34.0 · source

#### pub const fn get(self) -> u32

Returns the value as a primitive type.

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### impl NonZeroU32

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::NonZeroU32::new(u32::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::NonZeroU32::new(0b0101000).unwrap();

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

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### impl NonZeroU32

1.64.0 (const: 1.64.0) · source

#### pub const fn checked_add(self, other: u32) -> Option<NonZeroU32>

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 = NonZeroU32::new(1)?;
    let two = NonZeroU32::new(2)?;
    let max = NonZeroU32::new(u32::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: u32) -> NonZeroU32

Adds an unsigned integer to a non-zero value. Return `NonZeroU32::MAX` on overflow.

##### Examples

    let one = NonZeroU32::new(1)?;
    let two = NonZeroU32::new(2)?;
    let max = NonZeroU32::new(u32::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: u32) -> NonZeroU32

🔬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 > u32::MAX`.

##### Examples

    #![feature(nonzero_ops)]

    let one = NonZeroU32::new(1)?;
    let two = NonZeroU32::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<NonZeroU32>

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 = NonZeroU32::new(2)?;
    let three = NonZeroU32::new(3)?;
    let four = NonZeroU32::new(4)?;
    let max = NonZeroU32::new(u32::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 `u32::ilog2`, except that it has no failure cases to worry about since this value can never be zero.

##### Examples

    assert_eq!(NonZeroU32::new(7).unwrap().ilog2(), 2);
    assert_eq!(NonZeroU32::new(8).unwrap().ilog2(), 3);
    assert_eq!(NonZeroU32::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 `u32::ilog10`, except that it has no failure cases to worry about since this value can never be zero.

##### Examples

    assert_eq!(NonZeroU32::new(99).unwrap().ilog10(), 1);
    assert_eq!(NonZeroU32::new(100).unwrap().ilog10(), 2);
    assert_eq!(NonZeroU32::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 = NonZeroU32::new(1)?;
    let two = NonZeroU32::new(2)?;
    let four = NonZeroU32::new(4)?;

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

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### impl NonZeroU32

1.64.0 (const: 1.64.0) · source

#### pub const fn checked_mul(self, other: NonZeroU32) -> Option<NonZeroU32>

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 = NonZeroU32::new(2)?;
    let four = NonZeroU32::new(4)?;
    let max = NonZeroU32::new(u32::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: NonZeroU32) -> NonZeroU32

Multiplies two non-zero integers together. Return `NonZeroU32::MAX` on overflow.

##### Examples

    let two = NonZeroU32::new(2)?;
    let four = NonZeroU32::new(4)?;
    let max = NonZeroU32::new(u32::MAX)?;

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

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#### pub const unsafe fn unchecked_mul(self, other: NonZeroU32) -> NonZeroU32

🔬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 > u32::MAX`.

##### Examples

    #![feature(nonzero_ops)]

    let two = NonZeroU32::new(2)?;
    let four = NonZeroU32::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<NonZeroU32>

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 = NonZeroU32::new(3)?;
    let twenty_seven = NonZeroU32::new(27)?;
    let half_max = NonZeroU32::new(u32::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) -> NonZeroU32

Raise non-zero value to an integer power. Return `NonZeroU32::MAX` on overflow.

##### Examples

    let three = NonZeroU32::new(3)?;
    let twenty_seven = NonZeroU32::new(27)?;
    let max = NonZeroU32::new(u32::MAX)?;

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

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### impl NonZeroU32

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::NonZeroU32::new(8).unwrap();
    assert!(eight.is_power_of_two());
    let ten = std::num::NonZeroU32::new(10).unwrap();
    assert!(!ten.is_power_of_two());

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### impl NonZeroU32

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!(NonZeroU32::MIN.get(), 1u32);

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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 `u32::MAX`.

##### Examples

    assert_eq!(NonZeroU32::MAX.get(), u32::MAX);

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### impl NonZeroU32

1.67.0 · source

#### pub const BITS: u32 = 32u32

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

This value is equal to `u32::BITS`.

##### Examples

    assert_eq!(NonZeroU32::BITS, u32::BITS);

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## Trait Implementations§

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### impl Binary for NonZeroU32

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

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

### impl BitOr<NonZeroU32> for u32

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#### type Output = NonZeroU32

The resulting type after applying the `|` operator.
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#### fn bitor(self, rhs: NonZeroU32) -> Self::Output

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

### impl BitOr<u32> for NonZeroU32

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#### type Output = NonZeroU32

The resulting type after applying the `|` operator.
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#### fn bitor(self, rhs: u32) -> Self::Output

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

### impl BitOr for NonZeroU32

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#### type Output = NonZeroU32

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<u32> for NonZeroU32

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#### fn bitor_assign(&mut self, rhs: u32)

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

### impl BitOrAssign for NonZeroU32

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#### fn bitor_assign(&mut self, rhs: Self)

Performs the `|=` operation. Read more
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### impl Clone for NonZeroU32

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#### fn clone(&self) -> NonZeroU32

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 NonZeroU32

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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 NonZeroU32

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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<NonZeroU32> for u32

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#### fn div(self, other: NonZeroU32) -> u32

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

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#### type Output = u32

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

### impl From<NonZeroU16> for NonZeroU32

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#### fn from(small: NonZeroU16) -> Self

Converts `NonZeroU16` to `NonZeroU32` losslessly.

1.41.0 · source§

### impl From<NonZeroU32> for NonZeroI128

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#### fn from(small: NonZeroU32) -> Self

Converts `NonZeroU32` to `NonZeroI128` losslessly.

1.41.0 · source§

### impl From<NonZeroU32> for NonZeroI64

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#### fn from(small: NonZeroU32) -> Self

Converts `NonZeroU32` to `NonZeroI64` losslessly.

1.41.0 · source§

### impl From<NonZeroU32> for NonZeroU128

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#### fn from(small: NonZeroU32) -> Self

Converts `NonZeroU32` to `NonZeroU128` losslessly.

1.41.0 · source§

### impl From<NonZeroU32> for NonZeroU64

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#### fn from(small: NonZeroU32) -> Self

Converts `NonZeroU32` to `NonZeroU64` losslessly.

1.31.0 · source§

### impl From<NonZeroU32> for u32

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#### fn from(nonzero: NonZeroU32) -> Self

Converts a `NonZeroU32` into an `u32`

1.41.0 · source§

### impl From<NonZeroU8> for NonZeroU32

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#### fn from(small: NonZeroU8) -> Self

Converts `NonZeroU8` to `NonZeroU32` losslessly.

1.35.0 · source§

### impl FromStr for NonZeroU32

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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 NonZeroU32

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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 NonZeroU32

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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 NonZeroU32

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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 NonZeroU32

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#### fn cmp(&self, other: &NonZeroU32) -> Ordering

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

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

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

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

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

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

Restrict a value to a certain interval. Read more
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### impl PartialEq for NonZeroU32

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#### fn eq(&self, other: &NonZeroU32) -> 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 for NonZeroU32

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#### fn partial_cmp(&self, other: &NonZeroU32) -> 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<NonZeroU32> for u32

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#### fn rem(self, other: NonZeroU32) -> u32

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

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#### type Output = u32

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

### impl TryFrom<NonZeroI128> for NonZeroU32

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

Attempts to convert `NonZeroI128` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroI16` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroI32` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroI64` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroI8` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroIsize` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroU128` to `NonZeroU32`.

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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 NonZeroI16

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

Attempts to convert `NonZeroU32` to `NonZeroI16`.

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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 NonZeroI32

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

Attempts to convert `NonZeroU32` to `NonZeroI32`.

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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 NonZeroI8

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

Attempts to convert `NonZeroU32` 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<NonZeroU32> 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<NonZeroU32> for NonZeroU16

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

Attempts to convert `NonZeroU32` to `NonZeroU16`.

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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<NonZeroU32> for NonZeroUsize

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

Attempts to convert `NonZeroU32` to `NonZeroUsize`.

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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 NonZeroU32

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

Attempts to convert `NonZeroU64` to `NonZeroU32`.

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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 NonZeroU32

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

Attempts to convert `NonZeroUsize` to `NonZeroU32`.

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#### type Error = TryFromIntError

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

### impl TryFrom<u32> for NonZeroU32

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#### fn try_from(value: u32) -> Result<Self, Self::Error>

Attempts to convert `u32` to `NonZeroU32`.

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#### type Error = TryFromIntError

The type returned in the event of a conversion error.
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### impl UpperHex for NonZeroU32

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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 NonZeroU32

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### impl Eq for NonZeroU32

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### impl StructuralEq for NonZeroU32

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### impl StructuralPartialEq for NonZeroU32

## Auto Trait Implementations§

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### impl RefUnwindSafe for NonZeroU32

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### impl Send for NonZeroU32

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### impl Sync for NonZeroU32

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### impl Unpin for NonZeroU32

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### impl UnwindSafe for NonZeroU32

## Blanket Implementations§

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### impl<T> Any for T
where 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 T
where 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 T
where 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 T
where 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 T
where 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 T
where 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.