pub async fn copy<R, W>(reader: &mut R, writer: &mut W) -> Result<u64> where
R: Read + Unpin + ?Sized,
W: Write + Unpin + ?Sized,
Expand description
Copies the entire contents of a reader into a writer.
This function will continuously read data from reader
and then
write it into writer
in a streaming fashion until reader
returns EOF.
On success, the total number of bytes that were copied from
reader
to writer
is returned.
If you’re wanting to copy the contents of one file to another and you’re
working with filesystem paths, see the fs::copy
function.
This function is an async version of std::io::copy
.
Errors
This function will return an error immediately if any call to read
or
write
returns an error. All instances of ErrorKind::Interrupted
are
handled by this function and the underlying operation is retried.
Examples
use async_std::io;
let mut reader: &[u8] = b"hello";
let mut writer = io::stdout();
io::copy(&mut reader, &mut writer).await?;