diff --git a/library/std/src/io/buffered/mod.rs b/library/std/src/io/buffered/mod.rs index f9caeaf98e2..0b58e55ed17 100644 --- a/library/std/src/io/buffered/mod.rs +++ b/library/std/src/io/buffered/mod.rs @@ -126,6 +126,30 @@ pub fn error(&self) -> &Error { pub fn into_inner(self) -> W { self.0 } + + /// Consumes the [`IntoInnerError`] and returns the error which caused the call to + /// [`BufWriter::into_inner()`] to fail, and the underlying writer. + /// + /// This can be used to simply obtain ownership of the underlying error; it can also be used for + /// advanced error recovery. + /// + /// # Example + /// ``` + /// #![feature(io_into_inner_error_parts)] + /// use std::io::{BufWriter, ErrorKind, Write}; + /// + /// let mut not_enough_space = [0u8; 10]; + /// let mut stream = BufWriter::new(not_enough_space.as_mut()); + /// write!(stream, "this cannot be actually written").unwrap(); + /// let into_inner_err = stream.into_inner().expect_err("now we discover it's too small"); + /// let (err, recovered_writer) = into_inner_err.into_parts(); + /// assert_eq!(err.kind(), ErrorKind::WriteZero); + /// assert_eq!(recovered_writer.buffer(), b"t be actually written"); + /// ``` + #[unstable(feature = "io_into_inner_error_parts", issue = "79704")] + pub fn into_parts(self) -> (Error, W) { + (self.1, self.0) + } } #[stable(feature = "rust1", since = "1.0.0")]