5 files changed, 77 insertions, 7 deletions
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 14c850b6b05..14a16f3fc0f 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -24,9 +24,9 @@
 //!     let mut buffer = [0; 10];
 //!
 //!     // read up to 10 bytes
-//!     f.read(&mut buffer)?;
+//!     let n = f.read(&mut buffer)?;
 //!
-//!     println!("The bytes: {:?}", buffer);
+//!     println!("The bytes: {:?}", &buffer[..n]);
 //!     Ok(())
 //! }
 //! ```
@@ -56,9 +56,9 @@
 //!     f.seek(SeekFrom::End(-10))?;
 //!
 //!     // read up to 10 bytes
-//!     f.read(&mut buffer)?;
+//!     let n = f.read(&mut buffer)?;
 //!
-//!     println!("The bytes: {:?}", buffer);
+//!     println!("The bytes: {:?}", &buffer[..n]);
 //!     Ok(())
 //! }
 //! ```
@@ -537,7 +537,9 @@ pub trait Read {
     ///     let mut buffer = [0; 10];
     ///
     ///     // read up to 10 bytes
-    ///     f.read(&mut buffer[..])?;
+    ///     let n = f.read(&mut buffer[..])?;
+    ///
+    ///     println!("The bytes: {:?}", &buffer[..n]);
     ///     Ok(())
     /// }
     /// ```
@@ -1062,12 +1064,23 @@ impl Initializer {
 /// use std::fs::File;
 ///
 /// fn main() -> std::io::Result<()> {
+///     let data = b"some bytes";
+///
+///     let mut pos = 0;
 ///     let mut buffer = File::create("foo.txt")?;
 ///
-///     buffer.write(b"some bytes")?;
+///     while pos < data.len() {
+///         let bytes_written = buffer.write(&data[pos..])?;
+///         pos += bytes_written;
+///     }
 ///     Ok(())
 /// }
 /// ```
+///
+/// The trait also provides convenience methods like [`write_all`], which calls
+/// `write` in a loop until its entire input has been written.
+///
+/// [`write_all`]: #method.write_all
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(spotlight)]
 pub trait Write {
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index d5afd069d7f..0e0292277e1 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -233,10 +233,14 @@ macro_rules! eprintln {
 /// to give up ownership, you can instead borrow with `dbg!(&expr)`
 /// for some expression `expr`.
 ///
+/// The `dbg!` macro works exactly the same in release builds.
+/// This is useful when debugging issues that only occur in release
+/// builds or when debugging in release mode is significantly faster.
+///
 /// Note that the macro is intended as a debugging tool and therefore you
 /// should avoid having uses of it in version control for longer periods.
 /// Use cases involving debug output that should be added to version control
-/// may be better served by macros such as `debug!` from the `log` crate.
+/// are better served by macros such as [`debug!`][debug-log] from the [`log`][log] crate.
 ///
 /// # Stability
 ///
@@ -311,6 +315,8 @@ macro_rules! eprintln {
 /// file and line whenever it's reached.
 ///
 /// [stderr]: https://en.wikipedia.org/wiki/Standard_streams#Standard_error_(stderr)
+/// [debug-log]: https://docs.rs/log/*/log/macro.debug.html
+/// [log]: https://docs.rs/log/
 #[macro_export]
 #[stable(feature = "dbg_macro", since = "1.32.0")]
 macro_rules! dbg {
diff --git a/src/libstd/sys/redox/ext/io.rs b/src/libstd/sys/redox/ext/io.rs
index f431f96c541..c21d216478f 100644
--- a/src/libstd/sys/redox/ext/io.rs
+++ b/src/libstd/sys/redox/ext/io.rs
@@ -115,6 +115,21 @@ impl AsRawFd for io::Stderr {
     fn as_raw_fd(&self) -> RawFd { 2 }
 }
 
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdinLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { 0 }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdoutLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { 1 }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StderrLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { 2 }
+}
+
 #[stable(feature = "from_raw_os", since = "1.1.0")]
 impl FromRawFd for net::TcpStream {
     unsafe fn from_raw_fd(fd: RawFd) -> net::TcpStream {
diff --git a/src/libstd/sys/unix/ext/io.rs b/src/libstd/sys/unix/ext/io.rs
index 1a0b3b8962b..6bcc59495e3 100644
--- a/src/libstd/sys/unix/ext/io.rs
+++ b/src/libstd/sys/unix/ext/io.rs
@@ -95,3 +95,18 @@ impl AsRawFd for io::Stdout {
 impl AsRawFd for io::Stderr {
     fn as_raw_fd(&self) -> RawFd { libc::STDERR_FILENO }
 }
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdinLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { libc::STDIN_FILENO }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdoutLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { libc::STDOUT_FILENO }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StderrLock<'a> {
+    fn as_raw_fd(&self) -> RawFd { libc::STDERR_FILENO }
+}
diff --git a/src/libstd/sys/windows/ext/io.rs b/src/libstd/sys/windows/ext/io.rs
index 1a7d734b89e..ec47c2e9d5a 100644
--- a/src/libstd/sys/windows/ext/io.rs
+++ b/src/libstd/sys/windows/ext/io.rs
@@ -83,6 +83,27 @@ impl AsRawHandle for io::Stderr {
     }
 }
 
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawHandle for io::StdinLock<'a> {
+    fn as_raw_handle(&self) -> RawHandle {
+        unsafe { c::GetStdHandle(c::STD_INPUT_HANDLE) as RawHandle }
+    }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawHandle for io::StdoutLock<'a> {
+    fn as_raw_handle(&self) -> RawHandle {
+        unsafe { c::GetStdHandle(c::STD_OUTPUT_HANDLE) as RawHandle }
+    }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawHandle for io::StderrLock<'a> {
+    fn as_raw_handle(&self) -> RawHandle {
+        unsafe { c::GetStdHandle(c::STD_ERROR_HANDLE) as RawHandle }
+    }
+}
+
 #[stable(feature = "from_raw_os", since = "1.1.0")]
 impl FromRawHandle for fs::File {
     unsafe fn from_raw_handle(handle: RawHandle) -> fs::File {