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Struct std::string::FromUtf8Error

pub struct FromUtf8Error { /* fields omitted */ }

A possible error value when converting a String from a UTF-8 byte vector.

This type is the error type for the from_utf8 method on String. It is designed in such a way to carefully avoid reallocations: the into_bytes method will give back the byte vector that was used in the conversion attempt.

The Utf8Error type provided by std::str represents an error that may occur when converting a slice of u8s to a &str. In this sense, it's an analogue to FromUtf8Error, and you can get one from a FromUtf8Error through the utf8_error method.

Examples

Basic usage:

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert!(value.is_err());
assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());

Methods

impl FromUtf8Error [src]

ⓘImportant traits for &'a [u8]
impl<'a> Read for &'a [u8]
impl<'a> Write for &'a mut [u8]

Returns a slice of u8s bytes that were attempted to convert to a String.

Examples

Basic usage:

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert_eq!(&[0, 159], value.unwrap_err().as_bytes());

ⓘImportant traits for Vec<u8>
impl Write for Vec<u8>

Returns the bytes that were attempted to convert to a String.

This method is carefully constructed to avoid allocation. It will consume the error, moving out the bytes, so that a copy of the bytes does not need to be made.

Examples

Basic usage:

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());

Fetch a Utf8Error to get more details about the conversion failure.

The Utf8Error type provided by std::str represents an error that may occur when converting a slice of u8s to a &str. In this sense, it's an analogue to FromUtf8Error. See its documentation for more details on using it.

Examples

Basic usage:

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let error = String::from_utf8(bytes).unwrap_err().utf8_error();

// the first byte is invalid here
assert_eq!(1, error.valid_up_to());

Trait Implementations

impl Display for FromUtf8Error [src]

Formats the value using the given formatter. Read more

impl Debug for FromUtf8Error [src]

Formats the value using the given formatter. Read more

impl Error for FromUtf8Error [src]

This method is soft-deprecated. Read more

Deprecating in 1.33.0: replaced by Error::source, which can support downcasting

The lower-level cause of this error, if any. Read more

The lower-level source of this error, if any. Read more

Auto Trait Implementations

impl Send for FromUtf8Error

impl Sync for FromUtf8Error

Blanket Implementations

impl<T, U> TryFrom for T where
    T: From<U>, 
[src]

🔬 This is a nightly-only experimental API. (try_from #33417)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from #33417)

Performs the conversion.

impl<T> From for T [src]

Performs the conversion.

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
[src]

🔬 This is a nightly-only experimental API. (try_from #33417)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from #33417)

Performs the conversion.

impl<T, U> Into for T where
    U: From<T>, 
[src]

Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
[src]

ⓘImportant traits for &'a mut I
impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<'a, R: Read + ?Sized> Read for &'a mut R
impl<'a, W: Write + ?Sized> Write for &'a mut W

Immutably borrows from an owned value. Read more

impl<T> BorrowMut for T where
    T: ?Sized
[src]

ⓘImportant traits for &'a mut I
impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<'a, R: Read + ?Sized> Read for &'a mut R
impl<'a, W: Write + ?Sized> Write for &'a mut W

Mutably borrows from an owned value. Read more

impl<T> Any for T where
    T: 'static + ?Sized
[src]

🔬 This is a nightly-only experimental API. (get_type_id #27745)this method will likely be replaced by an associated static

Gets the TypeId of self. Read more

impl<T> ToString for T where
    T: Display + ?Sized
[src]

Converts the given value to a String. Read more

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/string/struct.FromUtf8Error.html