# Struct std::io::Empty

1.0.0 · source ·

    #[non_exhaustive]pub struct Empty;

Expand description

`Empty` ignores any data written via `Write`, and will always be empty (returning zero bytes) when read via `Read`.

This struct is generally created by calling `empty()`. Please see the documentation of `empty()` for more details.

## Trait Implementations§

source§

### impl BufRead for Empty

source§

#### fn fill_buf(&mut self) -> Result<&[u8]>

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
source§

#### fn consume(&mut self, _n: usize)

Tells this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `read`. Read more
source§

#### fn has_data_left(&mut self) -> Result<bool>

🔬This is a nightly-only experimental API. (`buf_read_has_data_left` #86423)
Check if the underlying `Read` has any data left to be read. Read more
source§

#### fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes into `buf` until the delimiter `byte` or EOF is reached. Read more
source§

#### fn read_line(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until a newline (the `0xA` byte) is reached, and append them to the provided `String` buffer. Read more
source§

#### fn split(self, byte: u8) -> Split<Self> ⓘwhere Self: Sized,

Returns an iterator over the contents of this reader split on the byte `byte`. Read more
source§

#### fn lines(self) -> Lines<Self> ⓘwhere Self: Sized,

Returns an iterator over the lines of this reader. Read more
source§

### impl Clone for Empty

source§

#### fn clone(&self) -> Empty ⓘ

Returns a copy of the value. Read more
source§

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

Performs copy-assignment from `source`. Read more
source§

### impl Debug for Empty

source§

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

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

### impl Default for Empty

source§

#### fn default() -> Empty ⓘ

Returns the “default value” for a type. Read more
source§

### impl Read for Empty

source§

#### fn read(&mut self, _buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
source§

#### fn read_buf(&mut self, _cursor: BorrowedCursor<'_>) -> Result<()>

🔬This is a nightly-only experimental API. (`read_buf` #78485)
Pull some bytes from this source into the specified buffer. Read more
1.36.0 · source§

#### fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like `read`, except that it reads into a slice of buffers. Read more
source§

#### fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (`can_vector` #69941)
Determines if this `Read`er has an efficient `read_vectored` implementation. Read more
source§

#### fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into `buf`. Read more
source§

#### fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to `buf`. Read more
1.6.0 · source§

#### fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill `buf`. Read more
source§

#### fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<()>

🔬This is a nightly-only experimental API. (`read_buf` #78485)
Read the exact number of bytes required to fill `cursor`. Read more
source§

#### fn by_ref(&mut self) -> &mut Self where Self: Sized,

Creates a “by reference” adaptor for this instance of `Read`. Read more
source§

#### fn bytes(self) -> Bytes<Self> ⓘwhere Self: Sized,

Transforms this `Read` instance to an `Iterator` over its bytes. Read more
source§

#### fn chain<R: Read>(self, next: R) -> Chain<Self, R> ⓘwhere Self: Sized,

Creates an adapter which will chain this stream with another. Read more
source§

#### fn take(self, limit: u64) -> Take<Self> ⓘwhere Self: Sized,

Creates an adapter which will read at most `limit` bytes from it. Read more
1.51.0 · source§

### impl Seek for Empty

source§

#### fn seek(&mut self, _pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream. Read more
source§

#### fn stream_len(&mut self) -> Result<u64>

🔬This is a nightly-only experimental API. (`seek_stream_len` #59359)
Returns the length of this stream (in bytes). Read more
source§

#### fn stream_position(&mut self) -> Result<u64>

Returns the current seek position from the start of the stream. Read more
1.55.0 · source§

#### fn rewind(&mut self) -> Result<()>

Rewind to the beginning of a stream. Read more
1.73.0 · source§

### impl Write for &Empty

source§

#### fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written. Read more
source§

#### fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like `write`, except that it writes from a slice of buffers. Read more
source§

#### fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (`can_vector` #69941)
Determines if this `Write`r has an efficient `write_vectored` implementation. Read more
source§

#### fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
source§

#### fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer. Read more
source§

#### fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬This is a nightly-only experimental API. (`write_all_vectored` #70436)
Attempts to write multiple buffers into this writer. Read more
source§

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

Writes a formatted string into this writer, returning any error encountered. Read more
source§

#### fn by_ref(&mut self) -> &mut Self where Self: Sized,

Creates a “by reference” adapter for this instance of `Write`. Read more
1.73.0 · source§

### impl Write for Empty

source§

#### fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written. Read more
source§

#### fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like `write`, except that it writes from a slice of buffers. Read more
source§

#### fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (`can_vector` #69941)
Determines if this `Write`r has an efficient `write_vectored` implementation. Read more
source§

#### fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
source§

#### fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer. Read more
source§

#### fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬This is a nightly-only experimental API. (`write_all_vectored` #70436)
Attempts to write multiple buffers into this writer. Read more
source§

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

Writes a formatted string into this writer, returning any error encountered. Read more
source§

#### fn by_ref(&mut self) -> &mut Self where Self: Sized,

Creates a “by reference” adapter for this instance of `Write`. Read more
source§

### impl Copy for Empty

## Auto Trait Implementations§

§

### impl RefUnwindSafe for Empty

§

### impl Send for Empty

§

### impl Sync for Empty

§

### impl Unpin for Empty

§

### impl UnwindSafe for Empty

## Blanket Implementations§

source§

### impl<T> Any for Twhere T: 'static + ?Sized,

source§

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
source§

### impl<T> Borrow<T> for Twhere T: ?Sized,

source§

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

### impl<T> BorrowMut<T> for Twhere T: ?Sized,

source§

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

### impl<T> From<T> for T

source§

#### fn from(t: T) -> T

Returns the argument unchanged.

source§

### impl<T, U> Into<U> for Twhere U: From<T>,

source§

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

source§

### impl<T> ToOwned for Twhere T: Clone,

§

#### type Owned = T

The resulting type after obtaining ownership.
source§

#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

### impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

#### type Error = Infallible

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

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

### impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

#### type Error = <U as TryFrom<T>>::Error

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

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.