Struct std::io::Empty

#[non_exhaustive]
pub struct Empty;

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

impl BufRead for Empty

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.

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.

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.

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.

fn skip_until(&mut self, byte: u8) -> Result<usize>

🔬This is a nightly-only experimental API. (bufread_skip_until #111735)

Skip all bytes until the delimiter byte or EOF is reached.

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.

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

Returns an iterator over the contents of this reader split on the byte byte.

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

Returns an iterator over the lines of this reader.

impl Clone for Empty

fn clone(&self) -> Empty

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Empty

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

Formats the value using the given formatter.

impl Default for Empty

fn default() -> Empty

Returns the “default value” for a type.

impl Read for Empty

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.

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.

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

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector #69941)

Determines if this Reader has an efficient read_vectored implementation.

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

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

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

Read all bytes until EOF in this source, appending them to buf.

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

Read the exact number of bytes required to fill buf.

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.

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

Creates a “by reference” adaptor for this instance of Read.

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

Transforms this Read instance to an Iterator over its bytes.

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

Creates an adapter which will chain this stream with another.

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

Creates an adapter which will read at most limit bytes from it.

impl Seek for Empty

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

Seek to an offset, in bytes, in a stream.

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).

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

Returns the current seek position from the start of the stream.

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

Rewind to the beginning of a stream.

fn seek_relative(&mut self, offset: i64) -> Result<()>

🔬This is a nightly-only experimental API. (seek_seek_relative #117374)

Seeks relative to the current position.

impl Write for &Empty

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

Write a buffer into this writer, returning how many bytes were written.

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

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector #69941)

Determines if this Writer has an efficient write_vectored implementation.

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

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

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.

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

Writes a formatted string into this writer, returning any error encountered.

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

Creates a “by reference” adapter for this instance of Write.

impl Write for Empty

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

Write a buffer into this writer, returning how many bytes were written.

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

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector #69941)

Determines if this Writer has an efficient write_vectored implementation.

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

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

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.

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

Writes a formatted string into this writer, returning any error encountered.

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

Creates a “by reference” adapter for this instance of Write.

impl Copy for Empty