## Error

# Struct Error

1.36.0 · Source

    pub struct Error;

Expand description

The error type which is returned from formatting a message into a stream.

This type does not support transmission of an error other than that an error occurred. This is because, despite the existence of this error, string formatting is considered an infallible operation. `fmt()` implementors should not return this `Error` unless they received it from their `Formatter`. The only time your code should create a new instance of this error is when implementing `fmt::Write`, in order to cancel the formatting operation when writing to the underlying stream fails.

Any extra information must be arranged to be transmitted through some other means, such as storing it in a field to be consulted after the formatting operation has been cancelled. (For example, this is how `std::io::Write::write_fmt()` propagates IO errors during writing.)

This type, `fmt::Error`, should not be confused with `std::io::Error` or `std::error::Error`, which you may also have in scope.

## §Examples

    use std::fmt::{self, write};

    let mut output = String::new();
    if let Err(fmt::Error) = write(&mut output, format_args!("Hello {}!", "world")) {
        panic!("An error occurred");
    }

## Trait Implementations§

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### impl Clone for Error

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

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for Error

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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 Default for Error

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#### fn default() -> Error

Returns the “default value” for a type. Read more
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### impl Display for Error

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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 Error for Error

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#### fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
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#### fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
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#### fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
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#### fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (`error_generic_member_access` #99301)
Provides type-based access to context intended for error reports. Read more
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### impl Hash for Error

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

Feeds this value into the given `Hasher`. Read more
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#### fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given `Hasher`. Read more
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### impl Ord for Error

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

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

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

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

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

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

Tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &Rhs) -> bool

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 Error

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#### fn partial_cmp(&self, other: &Error) -> 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: &Rhs) -> bool

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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#### fn le(&self, other: &Rhs) -> bool

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: &Rhs) -> bool

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
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#### fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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### impl Copy for Error

1.0.0 · Source§

### impl Eq for Error

1.0.0 · Source§

### impl StructuralPartialEq for Error

## Auto Trait Implementations§

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### impl Freeze for Error

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### impl RefUnwindSafe for Error

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### impl Send for Error

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### impl Sync for Error

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### impl Unpin for Error

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### impl UnwindSafe for Error

## 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> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. 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> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T> ToString for T
where T: Display + ?Sized,

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#### fn to_string(&self) -> String

Converts the given value to a `String`. Read more
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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.