std::io::copy - Rust
Description: API documentation for the Rust `copy` fn in crate `std`.
Keywords: rust, rustlang, rust-lang, copy

# Function std::io::copy 1.0.0 [−] [src]

    pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> Result<u64> where
        R: Read,
        W: Write,

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.

# 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 std::io;

    let mut reader: &[u8] = b"hello";
    let mut writer: Vec<u8> = vec![];

    io::copy(&mut reader, &mut writer)?;

    assert_eq!(&b"hello"[..], &writer[..]);Run

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