# Struct std::string::FromUtf8Error 1.0.0[−][src]

    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 `u8`s 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());Run

## Methods

###

`impl FromUtf8Error`

[src]

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`

`pub fn as_bytes(&self) -> &[u8]`

1.26.0
[src]

Returns a slice of `u8`s 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());Run

####
ⓘImportant traits for Vec<u8>

### Important traits for Vec<u8>

`impl Write for Vec<u8>`

`pub fn into_bytes(self) -> Vec<u8>`

[src]

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());Run

####

`pub fn utf8_error(&self) -> Utf8Error`

[src]

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 `u8`s 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());Run

## Trait Implementations

###

`impl Debug for FromUtf8Error`

[src]

####

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

[src]

Formats the value using the given formatter. Read more

###

`impl Display for FromUtf8Error`

[src]

####

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

[src]

Formats the value using the given formatter. Read more

###

`impl Error for FromUtf8Error`

[src]

####

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

[src]

This method is soft-deprecated. Read more

####

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

[src]

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

## Auto Trait Implementations

###

`impl Send for FromUtf8Error`

###

`impl Sync for FromUtf8Error`

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