# Type Alias core::num::NonZeroI8

1.34.0 · source ·

    pub type NonZeroI8 = NonZero<i8>;

Expand description

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, `Option<NonZeroI8>` is the same size as `i8`:

    use std::mem::size_of;
    assert_eq!(size_of::<Option<core::num::NonZeroI8>>(), size_of::<i8>());

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## §Layout

`NonZeroI8` is guaranteed to have the same layout and bit validity as `i8` with the exception that `0` is not a valid instance. `Option<NonZeroI8>` is guaranteed to be compatible with `i8`, including in FFI.

Thanks to the null pointer optimization, `NonZeroI8` and `Option<NonZeroI8>` are guaranteed to have the same size and alignment:

    use std::num::NonZeroI8;

    assert_eq!(size_of::<NonZeroI8>(), size_of::<Option<NonZeroI8>>());
    assert_eq!(align_of::<NonZeroI8>(), align_of::<Option<NonZeroI8>>());

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## Aliased Type§

    struct NonZeroI8(/* private fields */);

## Implementations§

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### impl NonZeroI8

const: 1.34.0 · source

#### pub const unsafe fn new_unchecked(n: i8) -> 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: i8) -> Option<Self>

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

source

#### pub unsafe fn from_mut_unchecked(n: &mut i8) -> &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.

source

#### pub fn from_mut(n: &mut i8) -> 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) -> i8

Returns the value as a primitive type.

1.67.0 · source

#### pub const BITS: u32 = 8u32

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

This value is equal to `i8::BITS`.

##### §Examples

    assert_eq!(NonZeroI8::BITS, i8::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::NonZeroI8::new(-1i8).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::NonZeroI8::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 = NonZeroI8::new(0b100_0000)?;
    let b = NonZeroI8::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 `i8::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!(NonZeroI8::MIN.get(), i8::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 `i8::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!(NonZeroI8::MAX.get(), i8::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 `i8::abs` for documentation on overflow behaviour.

##### §Example

    let pos = NonZeroI8::new(1)?;
    let neg = NonZeroI8::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 == NonZeroI8::MIN`. The result cannot be zero.

##### §Example

    let pos = NonZeroI8::new(1)?;
    let neg = NonZeroI8::new(-1)?;
    let min = NonZeroI8::new(i8::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 `i8::overflowing_abs`.

##### §Example

    let pos = NonZeroI8::new(1)?;
    let neg = NonZeroI8::new(-1)?;
    let min = NonZeroI8::new(i8::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 `i8::saturating_abs`.

##### §Example

    let pos = NonZeroI8::new(1)?;
    let neg = NonZeroI8::new(-1)?;
    let min = NonZeroI8::new(i8::MIN)?;
    let min_plus = NonZeroI8::new(i8::MIN + 1)?;
    let max = NonZeroI8::new(i8::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 `i8::wrapping_abs`.

##### §Example

    let pos = NonZeroI8::new(1)?;
    let neg = NonZeroI8::new(-1)?;
    let min = NonZeroI8::new(i8::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) -> NonZeroU8

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

##### §Example

    let u_pos = NonZeroU8::new(1)?;
    let i_pos = NonZeroI8::new(1)?;
    let i_neg = NonZeroI8::new(-1)?;
    let i_min = NonZeroI8::new(i8::MIN)?;
    let u_max = NonZeroU8::new(u8::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 = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::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 = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::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 == NonZeroI8::MIN`.

##### §Example

    let pos_five = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::new(-5)?;
    let min = NonZeroI8::new(i8::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 `i8::overflowing_neg` for documentation on overflow behaviour.

##### §Example

    let pos_five = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::new(-5)?;
    let min = NonZeroI8::new(i8::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 `NonZeroI8::MAX` if `self == NonZeroI8::MIN` instead of overflowing.

##### §Example

    let pos_five = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::new(-5)?;
    let min = NonZeroI8::new(i8::MIN)?;
    let min_plus_one = NonZeroI8::new(i8::MIN + 1)?;
    let max = NonZeroI8::new(i8::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 `i8::wrapping_neg` for documentation on overflow behaviour.

##### §Example

    let pos_five = NonZeroI8::new(5)?;
    let neg_five = NonZeroI8::new(-5)?;
    let min = NonZeroI8::new(i8::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 = NonZeroI8::new(2)?;
    let four = NonZeroI8::new(4)?;
    let max = NonZeroI8::new(i8::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 `NonZeroI8::MAX` on overflow.

##### §Examples

    let two = NonZeroI8::new(2)?;
    let four = NonZeroI8::new(4)?;
    let max = NonZeroI8::new(i8::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 > i8::MAX`, or `self * rhs < i8::MIN`.

##### §Examples

    #![feature(nonzero_ops)]

    let two = NonZeroI8::new(2)?;
    let four = NonZeroI8::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 = NonZeroI8::new(3)?;
    let twenty_seven = NonZeroI8::new(27)?;
    let half_max = NonZeroI8::new(i8::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 `NonZeroI8::MIN` or `NonZeroI8::MAX` on overflow.

##### §Examples

    let three = NonZeroI8::new(3)?;
    let twenty_seven = NonZeroI8::new(27)?;
    let max = NonZeroI8::new(i8::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 NonZeroI8

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

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

### impl BitOr<i8> for NonZeroI8

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#### type Output = NonZero<i8>

The resulting type after applying the `|` operator.
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#### fn bitor(self, rhs: i8) -> Self::Output

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

### impl BitOr for NonZeroI8

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#### type Output = NonZero<i8>

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<i8> for NonZeroI8

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#### fn bitor_assign(&mut self, rhs: i8)

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

### impl BitOrAssign for NonZeroI8

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

Performs the `|=` operation. Read more
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### impl Clone for NonZeroI8

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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 NonZeroI8

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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 NonZeroI8

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

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

### impl FromStr for NonZeroI8

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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 NonZeroI8

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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 NonZeroI8

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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 &NonZeroI8

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#### type Output = <NonZero<i8> as Neg>::Output

The resulting type after applying the `-` operator.
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#### fn neg(self) -> <NonZeroI8 as Neg>::Output

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

### impl Neg for NonZeroI8

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#### type Output = NonZero<i8>

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 NonZeroI8

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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 NonZeroI8

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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 NonZeroI8

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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 NonZeroI8

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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 NonZeroI8

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

Attempts to convert `NonZeroI128` 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<NonZero<i16>> for NonZeroI8

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

Attempts to convert `NonZeroI16` 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<NonZero<i32>> for NonZeroI8

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

Attempts to convert `NonZeroI32` 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<NonZero<i64>> for NonZeroI8

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

Attempts to convert `NonZeroI64` 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<NonZero<isize>> for NonZeroI8

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

Attempts to convert `NonZeroIsize` 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<NonZero<u128>> for NonZeroI8

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

Attempts to convert `NonZeroU128` 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<NonZero<u16>> for NonZeroI8

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

Attempts to convert `NonZeroU16` 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<NonZero<u32>> 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<NonZero<u64>> for NonZeroI8

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

Attempts to convert `NonZeroU64` 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<NonZero<u8>> 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<NonZero<usize>> for NonZeroI8

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

Attempts to convert `NonZeroUsize` to `NonZeroI8`.

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#### type Error = TryFromIntError

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

### impl TryFrom<i8> for NonZeroI8

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#### fn try_from(value: i8) -> Result<Self, Self::Error>

Attempts to convert `i8` to `NonZeroI8`.

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#### type Error = TryFromIntError

The type returned in the event of a conversion error.
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### impl UpperHex for NonZeroI8

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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 NonZeroI8

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### impl Eq for NonZeroI8

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### impl StructuralPartialEq for NonZeroI8