std::str::Utf8Error - Rust
Description: API documentation for the Rust `Utf8Error` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, Utf8Error

# Struct std::str::Utf8Error 1.0.0 [−] [src]

    pub struct Utf8Error { /* fields omitted */ }

Errors which can occur when attempting to interpret a sequence of `u8` as a string.

As such, the `from_utf8` family of functions and methods for both `String`s and `&str`s make use of this error, for example.

## Methods

### `impl Utf8Error`
[src]

#### `fn valid_up_to(&self) -> usize`
1.5.0

Returns the index in the given string up to which valid UTF-8 was verified.

It is the maximum index such that `from_utf8(&input[..index])` would return `Ok(_)`.

# Examples

Basic usage:

    use std::str;

    // some invalid bytes, in a vector
    let sparkle_heart = vec![0, 159, 146, 150];

    // std::str::from_utf8 returns a Utf8Error
    let error = str::from_utf8(&sparkle_heart).unwrap_err();

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

#### `fn error_len(&self) -> Option<usize>`
1.20.0

Provide more information about the failure:

- `None`: the end of the input was reached unexpectedly. `self.valid_up_to()` is 1 to 3 bytes from the end of the input. If a byte stream (such as a file or a network socket) is being decoded incrementally, this could be a valid `char` whose UTF-8 byte sequence is spanning multiple chunks.

- `Some(len)`: an unexpected byte was encountered. The length provided is that of the invalid byte sequence that starts at the index given by `valid_up_to()`. Decoding should resume after that sequence (after inserting a U+FFFD REPLACEMENT CHARACTER) in case of lossy decoding.

## Trait Implementations

### `impl Eq for Utf8Error`
[src]

### `impl Copy for Utf8Error`
[src]

### `impl Display for Utf8Error`
[src]

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

Formats the value using the given formatter. Read more

### `impl Clone for Utf8Error`
[src]

#### `fn clone(&self) -> Utf8Error`

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`

Performs copy-assignment from `source`. Read more

### `impl Debug for Utf8Error`
[src]

#### `fn fmt(&self, __arg_0: &mut Formatter) -> Result<(), Error>`

Formats the value using the given formatter.

### `impl PartialEq<Utf8Error> for Utf8Error`
[src]

#### `fn eq(&self, __arg_0: &Utf8Error) -> bool`

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, __arg_0: &Utf8Error) -> bool`

This method tests for `!=`.

### `impl Error for Utf8Error`
[src]

#### `fn description(&self) -> &str`

A short description of the error. Read more

#### `fn cause(&self) -> Option<&Error>`

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

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