diff --git a/ctr-std/src/io/lazy.rs b/ctr-std/src/io/lazy.rs
new file mode 100644
index 0000000..ce205c3
--- /dev/null
+++ b/ctr-std/src/io/lazy.rs
@@ -0,0 +1,68 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cell::Cell;
+use ptr;
+use sync::Arc;
+use sys_common;
+use sys_common::mutex::Mutex;
+
+pub struct Lazy<T> {
+    lock: Mutex,
+    ptr: Cell<*mut Arc<T>>,
+    init: fn() -> Arc<T>,
+}
+
+unsafe impl<T> Sync for Lazy<T> {}
+
+impl<T: Send + Sync + 'static> Lazy<T> {
+    pub const fn new(init: fn() -> Arc<T>) -> Lazy<T> {
+        Lazy {
+            lock: Mutex::new(),
+            ptr: Cell::new(ptr::null_mut()),
+            init: init
+        }
+    }
+
+    pub fn get(&'static self) -> Option<Arc<T>> {
+        unsafe {
+            self.lock.lock();
+            let ptr = self.ptr.get();
+            let ret = if ptr.is_null() {
+                Some(self.init())
+            } else if ptr as usize == 1 {
+                None
+            } else {
+                Some((*ptr).clone())
+            };
+            self.lock.unlock();
+            return ret
+        }
+    }
+
+    unsafe fn init(&'static self) -> Arc<T> {
+        // If we successfully register an at exit handler, then we cache the
+        // `Arc` allocation in our own internal box (it will get deallocated by
+        // the at exit handler). Otherwise we just return the freshly allocated
+        // `Arc`.
+        let registered = sys_common::at_exit(move || {
+            self.lock.lock();
+            let ptr = self.ptr.get();
+            self.ptr.set(1 as *mut _);
+            self.lock.unlock();
+            drop(Box::from_raw(ptr))
+        });
+        let ret = (self.init)();
+        if registered.is_ok() {
+            self.ptr.set(Box::into_raw(Box::new(ret.clone())));
+        }
+        ret
+    }
+}
diff --git a/ctr-std/src/io/mod.rs b/ctr-std/src/io/mod.rs
index 1653790..8cb7b2b 100644
--- a/ctr-std/src/io/mod.rs
+++ b/ctr-std/src/io/mod.rs
@@ -21,7 +21,7 @@
 //! of other types, and you can implement them for your types too. As such,
 //! you'll see a few different types of I/O throughout the documentation in
 //! this module: [`File`]s, [`TcpStream`]s, and sometimes even [`Vec<T>`]s. For
-//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//! example, [`Read`] adds a [`read()`] method, which we can use on `File`s:
 //!
 //! ```
 //! use std::io;
@@ -29,11 +29,11 @@
 //! use std::fs::File;
 //!
 //! # fn foo() -> io::Result<()> {
-//! let mut f = try!(File::open("foo.txt"));
+//! let mut f = File::open("foo.txt")?;
 //! let mut buffer = [0; 10];
 //!
 //! // read up to 10 bytes
-//! try!(f.read(&mut buffer));
+//! f.read(&mut buffer)?;
 //!
 //! println!("The bytes: {:?}", buffer);
 //! # Ok(())
@@ -58,14 +58,14 @@
 //! use std::fs::File;
 //!
 //! # fn foo() -> io::Result<()> {
-//! let mut f = try!(File::open("foo.txt"));
+//! let mut f = File::open("foo.txt")?;
 //! let mut buffer = [0; 10];
 //!
 //! // skip to the last 10 bytes of the file
-//! try!(f.seek(SeekFrom::End(-10)));
+//! f.seek(SeekFrom::End(-10))?;
 //!
 //! // read up to 10 bytes
-//! try!(f.read(&mut buffer));
+//! f.read(&mut buffer)?;
 //!
 //! println!("The bytes: {:?}", buffer);
 //! # Ok(())
@@ -93,12 +93,12 @@
 //! use std::fs::File;
 //!
 //! # fn foo() -> io::Result<()> {
-//! let f = try!(File::open("foo.txt"));
+//! let f = File::open("foo.txt")?;
 //! let mut reader = BufReader::new(f);
 //! let mut buffer = String::new();
 //!
 //! // read a line into buffer
-//! try!(reader.read_line(&mut buffer));
+//! reader.read_line(&mut buffer)?;
 //!
 //! println!("{}", buffer);
 //! # Ok(())
@@ -115,12 +115,12 @@
 //! use std::fs::File;
 //!
 //! # fn foo() -> io::Result<()> {
-//! let f = try!(File::create("foo.txt"));
+//! let f = File::create("foo.txt")?;
 //! {
 //!     let mut writer = BufWriter::new(f);
 //!
 //!     // write a byte to the buffer
-//!     try!(writer.write(&[42]));
+//!     writer.write(&[42])?;
 //!
 //! } // the buffer is flushed once writer goes out of scope
 //!
@@ -138,7 +138,7 @@
 //! # fn foo() -> io::Result<()> {
 //! let mut input = String::new();
 //!
-//! try!(io::stdin().read_line(&mut input));
+//! io::stdin().read_line(&mut input)?;
 //!
 //! println!("You typed: {}", input.trim());
 //! # Ok(())
@@ -152,7 +152,7 @@
 //! use std::io::prelude::*;
 //!
 //! # fn foo() -> io::Result<()> {
-//! try!(io::stdout().write(&[42]));
+//! io::stdout().write(&[42])?;
 //! # Ok(())
 //! # }
 //! ```
@@ -173,11 +173,11 @@
 //! use std::fs::File;
 //!
 //! # fn foo() -> io::Result<()> {
-//! let f = try!(File::open("foo.txt"));
+//! let f = File::open("foo.txt")?;
 //! let reader = BufReader::new(f);
 //!
 //! for line in reader.lines() {
-//!     println!("{}", try!(line));
+//!     println!("{}", line?);
 //! }
 //!
 //! # Ok(())
@@ -194,7 +194,7 @@
 //! use std::io;
 //!
 //! # fn foo() -> io::Result<()> {
-//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! io::copy(&mut io::stdin(), &mut io::stdout())?;
 //! # Ok(())
 //! # }
 //! ```
@@ -206,7 +206,7 @@
 //! Last, but certainly not least, is [`io::Result`]. This type is used
 //! as the return type of many `std::io` functions that can cause an error, and
 //! can be returned from your own functions as well. Many of the examples in this
-//! module use the [`try!`] macro:
+//! module use the [`?` operator]:
 //!
 //! ```
 //! use std::io;
@@ -214,7 +214,7 @@
 //! fn read_input() -> io::Result<()> {
 //!     let mut input = String::new();
 //!
-//!     try!(io::stdin().read_line(&mut input));
+//!     io::stdin().read_line(&mut input)?;
 //!
 //!     println!("You typed: {}", input.trim());
 //!
@@ -250,7 +250,8 @@
 //! [`println!`]: ../macro.println.html
 //! [`Lines`]: struct.Lines.html
 //! [`io::Result`]: type.Result.html
-//! [`try!`]: ../macro.try.html
+//! [`?` operator]: ../../book/syntax-index.html
+//! [`read()`]: trait.Read.html#tymethod.read
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
@@ -273,16 +274,21 @@ pub use self::error::{Result, Error, ErrorKind};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use self::print::{STDOUT, _print};
-
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
 
 pub mod prelude;
 mod buffered;
 mod cursor;
 mod error;
 mod impls;
+mod lazy;
 mod util;
-mod print;
+mod stdio;
 
 const DEFAULT_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE;
 
@@ -399,19 +405,19 @@ fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize>
 /// use std::fs::File;
 ///
 /// # fn foo() -> io::Result<()> {
-/// let mut f = try!(File::open("foo.txt"));
+/// let mut f = File::open("foo.txt")?;
 /// let mut buffer = [0; 10];
 ///
 /// // read up to 10 bytes
-/// try!(f.read(&mut buffer));
+/// f.read(&mut buffer)?;
 ///
 /// let mut buffer = vec![0; 10];
 /// // read the whole file
-/// try!(f.read_to_end(&mut buffer));
+/// f.read_to_end(&mut buffer)?;
 ///
 /// // read into a String, so that you don't need to do the conversion.
 /// let mut buffer = String::new();
-/// try!(f.read_to_string(&mut buffer));
+/// f.read_to_string(&mut buffer)?;
 ///
 /// // and more! See the other methods for more details.
 /// # Ok(())
@@ -459,11 +465,11 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = [0; 10];
     ///
     /// // read 10 bytes
-    /// try!(f.read(&mut buffer[..]));
+    /// f.read(&mut buffer[..])?;
     /// # Ok(())
     /// # }
     /// ```
@@ -501,11 +507,11 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = Vec::new();
     ///
     /// // read the whole file
-    /// try!(f.read_to_end(&mut buffer));
+    /// f.read_to_end(&mut buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -540,10 +546,10 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = String::new();
     ///
-    /// try!(f.read_to_string(&mut buffer));
+    /// f.read_to_string(&mut buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -600,11 +606,11 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = [0; 10];
     ///
     /// // read exactly 10 bytes
-    /// try!(f.read_exact(&mut buffer));
+    /// f.read_exact(&mut buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -643,7 +649,7 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = Vec::new();
     /// let mut other_buffer = Vec::new();
     ///
@@ -651,12 +657,12 @@ pub trait Read {
     ///     let reference = f.by_ref();
     ///
     ///     // read at most 5 bytes
-    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///     reference.take(5).read_to_end(&mut buffer)?;
     ///
     /// } // drop our &mut reference so we can use f again
     ///
     /// // original file still usable, read the rest
-    /// try!(f.read_to_end(&mut other_buffer));
+    /// f.read_to_end(&mut other_buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -682,7 +688,7 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     ///
     /// for byte in f.bytes() {
     ///     println!("{}", byte.unwrap());
@@ -719,7 +725,7 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     ///
     /// for c in f.chars() {
     ///     println!("{}", c.unwrap());
@@ -753,15 +759,15 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f1 = try!(File::open("foo.txt"));
-    /// let mut f2 = try!(File::open("bar.txt"));
+    /// let mut f1 = File::open("foo.txt")?;
+    /// let mut f2 = File::open("bar.txt")?;
     ///
     /// let mut handle = f1.chain(f2);
     /// let mut buffer = String::new();
     ///
     /// // read the value into a String. We could use any Read method here,
     /// // this is just one example.
-    /// try!(handle.read_to_string(&mut buffer));
+    /// handle.read_to_string(&mut buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -789,13 +795,13 @@ pub trait Read {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut f = File::open("foo.txt")?;
     /// let mut buffer = [0; 5];
     ///
     /// // read at most five bytes
     /// let mut handle = f.take(5);
     ///
-    /// try!(handle.read(&mut buffer));
+    /// handle.read(&mut buffer)?;
     /// # Ok(())
     /// # }
     /// ```
@@ -809,19 +815,23 @@ pub trait Read {
 ///
 /// Implementors of the `Write` trait are sometimes called 'writers'.
 ///
-/// Writers are defined by two required methods, `write()` and `flush()`:
+/// Writers are defined by two required methods, [`write()`] and [`flush()`]:
 ///
-/// * The `write()` method will attempt to write some data into the object,
+/// * The [`write()`] method will attempt to write some data into the object,
 ///   returning how many bytes were successfully written.
 ///
-/// * The `flush()` method is useful for adaptors and explicit buffers
+/// * The [`flush()`] method is useful for adaptors and explicit buffers
 ///   themselves for ensuring that all buffered data has been pushed out to the
 ///   'true sink'.
 ///
 /// Writers are intended to be composable with one another. Many implementors
-/// throughout `std::io` take and provide types which implement the `Write`
+/// throughout [`std::io`] take and provide types which implement the `Write`
 /// trait.
 ///
+/// [`write()`]: #tymethod.write
+/// [`flush()`]: #tymethod.flush
+/// [`std::io`]: index.html
+///
 /// # Examples
 ///
 /// ```
@@ -829,9 +839,9 @@ pub trait Read {
 /// use std::fs::File;
 ///
 /// # fn foo() -> std::io::Result<()> {
-/// let mut buffer = try!(File::create("foo.txt"));
+/// let mut buffer = File::create("foo.txt")?;
 ///
-/// try!(buffer.write(b"some bytes"));
+/// buffer.write(b"some bytes")?;
 /// # Ok(())
 /// # }
 /// ```
@@ -869,9 +879,9 @@ pub trait Write {
     /// use std::fs::File;
     ///
     /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = try!(File::create("foo.txt"));
+    /// let mut buffer = File::create("foo.txt")?;
     ///
-    /// try!(buffer.write(b"some bytes"));
+    /// buffer.write(b"some bytes")?;
     /// # Ok(())
     /// # }
     /// ```
@@ -894,10 +904,10 @@ pub trait Write {
     /// use std::fs::File;
     ///
     /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    /// let mut buffer = BufWriter::new(File::create("foo.txt")?);
     ///
-    /// try!(buffer.write(b"some bytes"));
-    /// try!(buffer.flush());
+    /// buffer.write(b"some bytes")?;
+    /// buffer.flush()?;
     /// # Ok(())
     /// # }
     /// ```
@@ -922,9 +932,9 @@ pub trait Write {
     /// use std::fs::File;
     ///
     /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = try!(File::create("foo.txt"));
+    /// let mut buffer = File::create("foo.txt")?;
     ///
-    /// try!(buffer.write_all(b"some bytes"));
+    /// buffer.write_all(b"some bytes")?;
     /// # Ok(())
     /// # }
     /// ```
@@ -971,12 +981,12 @@ pub trait Write {
     /// use std::fs::File;
     ///
     /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = try!(File::create("foo.txt"));
+    /// let mut buffer = File::create("foo.txt")?;
     ///
     /// // this call
-    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// write!(buffer, "{:.*}", 2, 1.234567)?;
     /// // turns into this:
-    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?;
     /// # Ok(())
     /// # }
     /// ```
@@ -1027,12 +1037,12 @@ pub trait Write {
     /// use std::fs::File;
     ///
     /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = try!(File::create("foo.txt"));
+    /// let mut buffer = File::create("foo.txt")?;
     ///
     /// let reference = buffer.by_ref();
     ///
     /// // we can use reference just like our original buffer
-    /// try!(reference.write_all(b"some bytes"));
+    /// reference.write_all(b"some bytes")?;
     /// # Ok(())
     /// # }
     /// ```
@@ -1059,10 +1069,10 @@ pub trait Write {
 /// use std::io::SeekFrom;
 ///
 /// # fn foo() -> io::Result<()> {
-/// let mut f = try!(File::open("foo.txt"));
+/// let mut f = File::open("foo.txt")?;
 ///
 /// // move the cursor 42 bytes from the start of the file
-/// try!(f.seek(SeekFrom::Start(42)));
+/// f.seek(SeekFrom::Start(42))?;
 /// # Ok(())
 /// # }
 /// ```
@@ -1183,7 +1193,7 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
 /// use std::fs::File;
 ///
 /// # fn foo() -> io::Result<()> {
-/// let f = try!(File::open("foo.txt"));
+/// let f = File::open("foo.txt")?;
 /// let f = BufReader::new(f);
 ///
 /// for line in f.lines() {
@@ -1297,7 +1307,7 @@ pub trait BufRead: Read {
     /// let mut stdin = stdin.lock();
     /// let mut buffer = Vec::new();
     ///
-    /// try!(stdin.read_until(b'a', &mut buffer));
+    /// stdin.read_until(b'a', &mut buffer)?;
     ///
     /// println!("{:?}", buffer);
     /// # Ok(())
@@ -1415,6 +1425,12 @@ pub trait BufRead: Read {
     ///     println!("{}", line.unwrap());
     /// }
     /// ```
+    ///
+    /// # Errors
+    ///
+    /// Each line of the iterator has the same error semantics as [`BufRead::read_line()`].
+    ///
+    /// [`BufRead::read_line()`]: trait.BufRead.html#method.read_line
     #[stable(feature = "rust1", since = "1.0.0")]
     fn lines(self) -> Lines<Self> where Self: Sized {
         Lines { buf: self }
@@ -1434,6 +1450,16 @@ pub struct Chain<T, U> {
     done_first: bool,
 }
 
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl<T: fmt::Debug, U: fmt::Debug> fmt::Debug for Chain<T, U> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Chain")
+            .field("t", &self.first)
+            .field("u", &self.second)
+            .finish()
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Read, U: Read> Read for Chain<T, U> {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
@@ -1470,11 +1496,12 @@ impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
 
 /// Reader adaptor which limits the bytes read from an underlying reader.
 ///
-/// This struct is generally created by calling [`take()`][take] on a reader.
-/// Please see the documentation of `take()` for more details.
+/// This struct is generally created by calling [`take()`] on a reader.
+/// Please see the documentation of [`take()`] for more details.
 ///
-/// [take]: trait.Read.html#method.take
+/// [`take()`]: trait.Read.html#method.take
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Take<T> {
     inner: T,
     limit: u64,
@@ -1486,8 +1513,10 @@ impl<T> Take<T> {
     ///
     /// # Note
     ///
-    /// This instance may reach EOF after reading fewer bytes than indicated by
-    /// this method if the underlying `Read` instance reaches EOF.
+    /// This instance may reach `EOF` after reading fewer bytes than indicated by
+    /// this method if the underlying [`Read`] instance reaches EOF.
+    ///
+    /// [`Read`]: ../../std/io/trait.Read.html
     ///
     /// # Examples
     ///
@@ -1497,7 +1526,7 @@ impl<T> Take<T> {
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let f = try!(File::open("foo.txt"));
+    /// let f = File::open("foo.txt")?;
     ///
     /// // read at most five bytes
     /// let handle = f.take(5);
@@ -1514,24 +1543,22 @@ impl<T> Take<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(io_take_into_inner)]
-    ///
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
     /// # fn foo() -> io::Result<()> {
-    /// let mut file = try!(File::open("foo.txt"));
+    /// let mut file = File::open("foo.txt")?;
     ///
     /// let mut buffer = [0; 5];
     /// let mut handle = file.take(5);
-    /// try!(handle.read(&mut buffer));
+    /// handle.read(&mut buffer)?;
     ///
     /// let file = handle.into_inner();
     /// # Ok(())
     /// # }
     /// ```
-    #[unstable(feature = "io_take_into_inner", issue = "23755")]
+    #[stable(feature = "io_take_into_inner", since = "1.15.0")]
     pub fn into_inner(self) -> T {
         self.inner
     }
@@ -1592,6 +1619,7 @@ fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
 ///
 /// [`bytes()`]: trait.Read.html#method.bytes
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Bytes<R> {
     inner: R,
 }
@@ -1613,6 +1641,7 @@ impl<R: Read> Iterator for Bytes<R> {
 /// [chars]: trait.Read.html#method.chars
 #[unstable(feature = "io", reason = "awaiting stability of Read::chars",
            issue = "27802")]
+#[derive(Debug)]
 pub struct Chars<R> {
     inner: R,
 }
@@ -1702,6 +1731,7 @@ impl fmt::Display for CharsError {
 ///
 /// [split]: trait.BufRead.html#method.split
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Split<B> {
     buf: B,
     delim: u8,
@@ -1733,6 +1763,7 @@ impl<B: BufRead> Iterator for Split<B> {
 ///
 /// [lines]: trait.BufRead.html#method.lines
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Lines<B> {
     buf: B,
 }
diff --git a/ctr-std/src/io/print.rs b/ctr-std/src/io/print.rs
deleted file mode 100644
index 8a5851b..0000000
--- a/ctr-std/src/io/print.rs
+++ /dev/null
@@ -1,33 +0,0 @@
-use fmt;
-use io::{self, Write};
-
-// NOTE: We're just gonna use the spin mutex until we figure out how to properly
-// implement mutexes with ctrulib functions
-use spin::Mutex;
-use libc;
-
-pub static STDOUT: Mutex<StdoutRaw> = Mutex::new(StdoutRaw(()));
-
-pub struct StdoutRaw(());
-
-#[stable(feature = "3ds", since = "1.0.0")]
-impl Write for StdoutRaw {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        unsafe {
-            // devkitPro's version of write(2) fails if zero bytes are written,
-            // so let's just exit if the buffer size is zero
-            if buf.is_empty() {
-                return Ok(buf.len())
-            }
-            libc::write(libc::STDOUT_FILENO, buf.as_ptr() as *const _, buf.len());
-            Ok(buf.len())
-        }
-    }
-
-    fn flush(&mut self) -> io::Result<()> { Ok(()) }
-}
-
-#[doc(hidden)]
-pub fn _print(args: fmt::Arguments) {
-    STDOUT.lock().write_fmt(args).unwrap();
-}
diff --git a/ctr-std/src/io/stdio.rs b/ctr-std/src/io/stdio.rs
new file mode 100644
index 0000000..e16e801
--- /dev/null
+++ b/ctr-std/src/io/stdio.rs
@@ -0,0 +1,722 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cell::RefCell;
+use fmt;
+use io::lazy::Lazy;
+use io::{self, BufReader, LineWriter};
+use sync::{Arc, Mutex, MutexGuard};
+use sys::stdio;
+use sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
+use thread::LocalKeyState;
+
+/// Stdout used by print! and println! macros
+thread_local! {
+    static LOCAL_STDOUT: RefCell<Option<Box<Write + Send>>> = {
+        RefCell::new(None)
+    }
+}
+
+/// A handle to a raw instance of the standard input stream of this process.
+///
+/// This handle is not synchronized or buffered in any fashion. Constructed via
+/// the `std::io::stdio::stdin_raw` function.
+struct StdinRaw(stdio::Stdin);
+
+/// A handle to a raw instance of the standard output stream of this process.
+///
+/// This handle is not synchronized or buffered in any fashion. Constructed via
+/// the `std::io::stdio::stdout_raw` function.
+struct StdoutRaw(stdio::Stdout);
+
+/// A handle to a raw instance of the standard output stream of this process.
+///
+/// This handle is not synchronized or buffered in any fashion. Constructed via
+/// the `std::io::stdio::stderr_raw` function.
+struct StderrRaw(stdio::Stderr);
+
+/// Constructs a new raw handle to the standard input of this process.
+///
+/// The returned handle does not interact with any other handles created nor
+/// handles returned by `std::io::stdin`. Data buffered by the `std::io::stdin`
+/// handles is **not** available to raw handles returned from this function.
+///
+/// The returned handle has no external synchronization or buffering.
+fn stdin_raw() -> io::Result<StdinRaw> { stdio::Stdin::new().map(StdinRaw) }
+
+/// Constructs a new raw handle to the standard output stream of this process.
+///
+/// The returned handle does not interact with any other handles created nor
+/// handles returned by `std::io::stdout`. Note that data is buffered by the
+/// `std::io::stdout` handles so writes which happen via this raw handle may
+/// appear before previous writes.
+///
+/// The returned handle has no external synchronization or buffering layered on
+/// top.
+fn stdout_raw() -> io::Result<StdoutRaw> { stdio::Stdout::new().map(StdoutRaw) }
+
+/// Constructs a new raw handle to the standard error stream of this process.
+///
+/// The returned handle does not interact with any other handles created nor
+/// handles returned by `std::io::stderr`.
+///
+/// The returned handle has no external synchronization or buffering layered on
+/// top.
+fn stderr_raw() -> io::Result<StderrRaw> { stdio::Stderr::new().map(StderrRaw) }
+
+impl Read for StdinRaw {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { self.0.read(buf) }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        self.0.read_to_end(buf)
+    }
+}
+impl Write for StdoutRaw {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.write(buf) }
+    fn flush(&mut self) -> io::Result<()> { self.0.flush() }
+}
+impl Write for StderrRaw {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.write(buf) }
+    fn flush(&mut self) -> io::Result<()> { self.0.flush() }
+}
+
+enum Maybe<T> {
+    Real(T),
+    Fake,
+}
+
+impl<W: io::Write> io::Write for Maybe<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match *self {
+            Maybe::Real(ref mut w) => handle_ebadf(w.write(buf), buf.len()),
+            Maybe::Fake => Ok(buf.len())
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        match *self {
+            Maybe::Real(ref mut w) => handle_ebadf(w.flush(), ()),
+            Maybe::Fake => Ok(())
+        }
+    }
+}
+
+impl<R: io::Read> io::Read for Maybe<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        match *self {
+            Maybe::Real(ref mut r) => handle_ebadf(r.read(buf), 0),
+            Maybe::Fake => Ok(0)
+        }
+    }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        match *self {
+            Maybe::Real(ref mut r) => handle_ebadf(r.read_to_end(buf), 0),
+            Maybe::Fake => Ok(0)
+        }
+    }
+}
+
+fn handle_ebadf<T>(r: io::Result<T>, default: T) -> io::Result<T> {
+    use sys::stdio::EBADF_ERR;
+
+    match r {
+        Err(ref e) if e.raw_os_error() == Some(EBADF_ERR) => Ok(default),
+        r => r
+    }
+}
+
+/// A handle to the standard input stream of a process.
+///
+/// Each handle is a shared reference to a global buffer of input data to this
+/// process. A handle can be `lock`'d to gain full access to [`BufRead`] methods
+/// (e.g. `.lines()`). Reads to this handle are otherwise locked with respect
+/// to other reads.
+///
+/// This handle implements the `Read` trait, but beware that concurrent reads
+/// of `Stdin` must be executed with care.
+///
+/// Created by the [`io::stdin`] method.
+///
+/// [`io::stdin`]: fn.stdin.html
+/// [`BufRead`]: trait.BufRead.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Stdin {
+    inner: Arc<Mutex<BufReader<Maybe<StdinRaw>>>>,
+}
+
+/// A locked reference to the `Stdin` handle.
+///
+/// This handle implements both the [`Read`] and [`BufRead`] traits, and
+/// is constructed via the [`Stdin::lock`] method.
+///
+/// [`Read`]: trait.Read.html
+/// [`BufRead`]: trait.BufRead.html
+/// [`Stdin::lock`]: struct.Stdin.html#method.lock
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct StdinLock<'a> {
+    inner: MutexGuard<'a, BufReader<Maybe<StdinRaw>>>,
+}
+
+/// Constructs a new handle to the standard input of the current process.
+///
+/// Each handle returned is a reference to a shared global buffer whose access
+/// is synchronized via a mutex. If you need more explicit control over
+/// locking, see the [`lock() method`][lock].
+///
+/// [lock]: struct.Stdin.html#method.lock
+///
+/// # Examples
+///
+/// Using implicit synchronization:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// # fn foo() -> io::Result<String> {
+/// let mut buffer = String::new();
+/// io::stdin().read_to_string(&mut buffer)?;
+/// # Ok(buffer)
+/// # }
+/// ```
+///
+/// Using explicit synchronization:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// # fn foo() -> io::Result<String> {
+/// let mut buffer = String::new();
+/// let stdin = io::stdin();
+/// let mut handle = stdin.lock();
+///
+/// handle.read_to_string(&mut buffer)?;
+/// # Ok(buffer)
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn stdin() -> Stdin {
+    static INSTANCE: Lazy<Mutex<BufReader<Maybe<StdinRaw>>>> = Lazy::new(stdin_init);
+    return Stdin {
+        inner: INSTANCE.get().expect("cannot access stdin during shutdown"),
+    };
+
+    fn stdin_init() -> Arc<Mutex<BufReader<Maybe<StdinRaw>>>> {
+        let stdin = match stdin_raw() {
+            Ok(stdin) => Maybe::Real(stdin),
+            _ => Maybe::Fake
+        };
+
+        Arc::new(Mutex::new(BufReader::with_capacity(stdio::STDIN_BUF_SIZE, stdin)))
+    }
+}
+
+impl Stdin {
+    /// Locks this handle to the standard input stream, returning a readable
+    /// guard.
+    ///
+    /// The lock is released when the returned lock goes out of scope. The
+    /// returned guard also implements the [`Read`] and [`BufRead`] traits for
+    /// accessing the underlying data.
+    ///
+    /// [`Read`]: trait.Read.html
+    /// [`BufRead`]: trait.BufRead.html
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{self, Read};
+    ///
+    /// # fn foo() -> io::Result<String> {
+    /// let mut buffer = String::new();
+    /// let stdin = io::stdin();
+    /// let mut handle = stdin.lock();
+    ///
+    /// handle.read_to_string(&mut buffer)?;
+    /// # Ok(buffer)
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn lock(&self) -> StdinLock {
+        StdinLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) }
+    }
+
+    /// Locks this handle and reads a line of input into the specified buffer.
+    ///
+    /// For detailed semantics of this method, see the documentation on
+    /// [`BufRead::read_line`].
+    ///
+    /// [`BufRead::read_line`]: trait.BufRead.html#method.read_line
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io;
+    ///
+    /// let mut input = String::new();
+    /// match io::stdin().read_line(&mut input) {
+    ///     Ok(n) => {
+    ///         println!("{} bytes read", n);
+    ///         println!("{}", input);
+    ///     }
+    ///     Err(error) => println!("error: {}", error),
+    /// }
+    /// ```
+    ///
+    /// You can run the example one of two ways:
+    ///
+    /// - Pipe some text to it, e.g. `printf foo | path/to/executable`
+    /// - Give it text interactively by running the executable directly,
+    ///   in which case it will wait for the Enter key to be pressed before
+    ///   continuing
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn read_line(&self, buf: &mut String) -> io::Result<usize> {
+        self.lock().read_line(buf)
+    }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl fmt::Debug for Stdin {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stdin { .. }")
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Stdin {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.lock().read(buf)
+    }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        self.lock().read_to_end(buf)
+    }
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        self.lock().read_to_string(buf)
+    }
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        self.lock().read_exact(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for StdinLock<'a> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.inner.read(buf)
+    }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        self.inner.read_to_end(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for StdinLock<'a> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { self.inner.fill_buf() }
+    fn consume(&mut self, n: usize) { self.inner.consume(n) }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl<'a> fmt::Debug for StdinLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StdinLock { .. }")
+    }
+}
+
+/// A handle to the global standard output stream of the current process.
+///
+/// Each handle shares a global buffer of data to be written to the standard
+/// output stream. Access is also synchronized via a lock and explicit control
+/// over locking is available via the [`lock()`] method.
+///
+/// Created by the [`io::stdout`] method.
+///
+/// [`lock()`]: #method.lock
+/// [`io::stdout`]: fn.stdout.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Stdout {
+    // FIXME: this should be LineWriter or BufWriter depending on the state of
+    //        stdout (tty or not). Note that if this is not line buffered it
+    //        should also flush-on-panic or some form of flush-on-abort.
+    inner: Arc<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>>,
+}
+
+/// A locked reference to the `Stdout` handle.
+///
+/// This handle implements the [`Write`] trait, and is constructed via
+/// the [`Stdout::lock`] method.
+///
+/// [`Write`]: trait.Write.html
+/// [`Stdout::lock`]: struct.Stdout.html#method.lock
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct StdoutLock<'a> {
+    inner: ReentrantMutexGuard<'a, RefCell<LineWriter<Maybe<StdoutRaw>>>>,
+}
+
+/// Constructs a new handle to the standard output of the current process.
+///
+/// Each handle returned is a reference to a shared global buffer whose access
+/// is synchronized via a mutex. If you need more explicit control over
+/// locking, see the [Stdout::lock] method.
+///
+/// [Stdout::lock]: struct.Stdout.html#method.lock
+///
+/// # Examples
+///
+/// Using implicit synchronization:
+///
+/// ```
+/// use std::io::{self, Write};
+///
+/// # fn foo() -> io::Result<()> {
+/// io::stdout().write(b"hello world")?;
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+/// Using explicit synchronization:
+///
+/// ```
+/// use std::io::{self, Write};
+///
+/// # fn foo() -> io::Result<()> {
+/// let stdout = io::stdout();
+/// let mut handle = stdout.lock();
+///
+/// handle.write(b"hello world")?;
+///
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn stdout() -> Stdout {
+    static INSTANCE: Lazy<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>>
+        = Lazy::new(stdout_init);
+    return Stdout {
+        inner: INSTANCE.get().expect("cannot access stdout during shutdown"),
+    };
+
+    fn stdout_init() -> Arc<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>> {
+        let stdout = match stdout_raw() {
+            Ok(stdout) => Maybe::Real(stdout),
+            _ => Maybe::Fake,
+        };
+        Arc::new(ReentrantMutex::new(RefCell::new(LineWriter::new(stdout))))
+    }
+}
+
+impl Stdout {
+    /// Locks this handle to the standard output stream, returning a writable
+    /// guard.
+    ///
+    /// The lock is released when the returned lock goes out of scope. The
+    /// returned guard also implements the `Write` trait for writing data.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{self, Write};
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let stdout = io::stdout();
+    /// let mut handle = stdout.lock();
+    ///
+    /// handle.write(b"hello world")?;
+    ///
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn lock(&self) -> StdoutLock {
+        StdoutLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) }
+    }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl fmt::Debug for Stdout {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stdout { .. }")
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Stdout {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.lock().write(buf)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.lock().flush()
+    }
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.lock().write_all(buf)
+    }
+    fn write_fmt(&mut self, args: fmt::Arguments) -> io::Result<()> {
+        self.lock().write_fmt(args)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for StdoutLock<'a> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.inner.borrow_mut().write(buf)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.borrow_mut().flush()
+    }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl<'a> fmt::Debug for StdoutLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StdoutLock { .. }")
+    }
+}
+
+/// A handle to the standard error stream of a process.
+///
+/// For more information, see the [`io::stderr`] method.
+///
+/// [`io::stderr`]: fn.stderr.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Stderr {
+    inner: Arc<ReentrantMutex<RefCell<Maybe<StderrRaw>>>>,
+}
+
+/// A locked reference to the `Stderr` handle.
+///
+/// This handle implements the `Write` trait and is constructed via
+/// the [`Stderr::lock`] method.
+///
+/// [`Stderr::lock`]: struct.Stderr.html#method.lock
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct StderrLock<'a> {
+    inner: ReentrantMutexGuard<'a, RefCell<Maybe<StderrRaw>>>,
+}
+
+/// Constructs a new handle to the standard error of the current process.
+///
+/// This handle is not buffered.
+///
+/// # Examples
+///
+/// Using implicit synchronization:
+///
+/// ```
+/// use std::io::{self, Write};
+///
+/// # fn foo() -> io::Result<()> {
+/// io::stderr().write(b"hello world")?;
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+/// Using explicit synchronization:
+///
+/// ```
+/// use std::io::{self, Write};
+///
+/// # fn foo() -> io::Result<()> {
+/// let stderr = io::stderr();
+/// let mut handle = stderr.lock();
+///
+/// handle.write(b"hello world")?;
+///
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn stderr() -> Stderr {
+    static INSTANCE: Lazy<ReentrantMutex<RefCell<Maybe<StderrRaw>>>> = Lazy::new(stderr_init);
+    return Stderr {
+        inner: INSTANCE.get().expect("cannot access stderr during shutdown"),
+    };
+
+    fn stderr_init() -> Arc<ReentrantMutex<RefCell<Maybe<StderrRaw>>>> {
+        let stderr = match stderr_raw() {
+            Ok(stderr) => Maybe::Real(stderr),
+            _ => Maybe::Fake,
+        };
+        Arc::new(ReentrantMutex::new(RefCell::new(stderr)))
+    }
+}
+
+impl Stderr {
+    /// Locks this handle to the standard error stream, returning a writable
+    /// guard.
+    ///
+    /// The lock is released when the returned lock goes out of scope. The
+    /// returned guard also implements the `Write` trait for writing data.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{self, Write};
+    ///
+    /// fn foo() -> io::Result<()> {
+    ///     let stderr = io::stderr();
+    ///     let mut handle = stderr.lock();
+    ///
+    ///     handle.write(b"hello world")?;
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn lock(&self) -> StderrLock {
+        StderrLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) }
+    }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl fmt::Debug for Stderr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stderr { .. }")
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Stderr {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.lock().write(buf)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.lock().flush()
+    }
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.lock().write_all(buf)
+    }
+    fn write_fmt(&mut self, args: fmt::Arguments) -> io::Result<()> {
+        self.lock().write_fmt(args)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for StderrLock<'a> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.inner.borrow_mut().write(buf)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.borrow_mut().flush()
+    }
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl<'a> fmt::Debug for StderrLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StderrLock { .. }")
+    }
+}
+
+/// Resets the thread-local stderr handle to the specified writer
+///
+/// This will replace the current thread's stderr handle, returning the old
+/// handle. All future calls to `panic!` and friends will emit their output to
+/// this specified handle.
+///
+/// Note that this does not need to be called for all new threads; the default
+/// output handle is to the process's stderr stream.
+#[unstable(feature = "set_stdio",
+           reason = "this function may disappear completely or be replaced \
+                     with a more general mechanism",
+           issue = "0")]
+#[doc(hidden)]
+pub fn set_panic(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
+    use panicking::LOCAL_STDERR;
+    use mem;
+    LOCAL_STDERR.with(move |slot| {
+        mem::replace(&mut *slot.borrow_mut(), sink)
+    }).and_then(|mut s| {
+        let _ = s.flush();
+        Some(s)
+    })
+}
+
+/// Resets the thread-local stdout handle to the specified writer
+///
+/// This will replace the current thread's stdout handle, returning the old
+/// handle. All future calls to `print!` and friends will emit their output to
+/// this specified handle.
+///
+/// Note that this does not need to be called for all new threads; the default
+/// output handle is to the process's stdout stream.
+#[unstable(feature = "set_stdio",
+           reason = "this function may disappear completely or be replaced \
+                     with a more general mechanism",
+           issue = "0")]
+#[doc(hidden)]
+pub fn set_print(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
+    use mem;
+    LOCAL_STDOUT.with(move |slot| {
+        mem::replace(&mut *slot.borrow_mut(), sink)
+    }).and_then(|mut s| {
+        let _ = s.flush();
+        Some(s)
+    })
+}
+
+#[unstable(feature = "print",
+           reason = "implementation detail which may disappear or be replaced at any time",
+           issue = "0")]
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+    // As an implementation of the `println!` macro, we want to try our best to
+    // not panic wherever possible and get the output somewhere. There are
+    // currently two possible vectors for panics we take care of here:
+    //
+    // 1. If the TLS key for the local stdout has been destroyed, accessing it
+    //    would cause a panic. Note that we just lump in the uninitialized case
+    //    here for convenience, we're not trying to avoid a panic.
+    // 2. If the local stdout is currently in use (e.g. we're in the middle of
+    //    already printing) then accessing again would cause a panic.
+    //
+    // If, however, the actual I/O causes an error, we do indeed panic.
+    let result = match LOCAL_STDOUT.state() {
+        LocalKeyState::Uninitialized |
+        LocalKeyState::Destroyed => stdout().write_fmt(args),
+        LocalKeyState::Valid => {
+            LOCAL_STDOUT.with(|s| {
+                if let Ok(mut borrowed) = s.try_borrow_mut() {
+                    if let Some(w) = borrowed.as_mut() {
+                        return w.write_fmt(args);
+                    }
+                }
+                stdout().write_fmt(args)
+            })
+        }
+    };
+    if let Err(e) = result {
+        panic!("failed printing to stdout: {}", e);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use thread;
+    use super::*;
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn panic_doesnt_poison() {
+        thread::spawn(|| {
+            let _a = stdin();
+            let _a = _a.lock();
+            let _a = stdout();
+            let _a = _a.lock();
+            let _a = stderr();
+            let _a = _a.lock();
+            panic!();
+        }).join().unwrap_err();
+
+        let _a = stdin();
+        let _a = _a.lock();
+        let _a = stdout();
+        let _a = _a.lock();
+        let _a = stderr();
+        let _a = _a.lock();
+    }
+}
diff --git a/ctr-std/src/lib.rs b/ctr-std/src/lib.rs
index 64d76a2..307bb3c 100644
--- a/ctr-std/src/lib.rs
+++ b/ctr-std/src/lib.rs
@@ -11,6 +11,7 @@
 #![feature(char_escape_debug)]
 #![feature(dropck_eyepatch)]
 #![feature(float_extras)]
+#![feature(fnbox)]
 #![feature(fused)]
 #![feature(generic_param_attrs)]
 #![feature(int_error_internals)]
diff --git a/ctr-std/src/panicking.rs b/ctr-std/src/panicking.rs
index d6b922d..e0f9477 100644
--- a/ctr-std/src/panicking.rs
+++ b/ctr-std/src/panicking.rs
@@ -11,10 +11,19 @@
 //! Implementation of various bits and pieces of the `panic!` macro and
 //! associated runtime pieces.
 
+use io::prelude::*;
+
 use any::Any;
+use cell::RefCell;
 use fmt;
 use __core::fmt::Display;
 
+thread_local! {
+    pub static LOCAL_STDERR: RefCell<Option<Box<Write + Send>>> = {
+        RefCell::new(None)
+    }
+}
+
 ///The compiler wants this to be here. Otherwise it won't be happy. And we like happy compilers.
 #[lang = "eh_personality"]
 extern fn eh_personality() {}
diff --git a/ctr-std/src/sys/unix/fd.rs b/ctr-std/src/sys/unix/fd.rs
new file mode 100644
index 0000000..917a34b
--- /dev/null
+++ b/ctr-std/src/sys/unix/fd.rs
@@ -0,0 +1,137 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![unstable(reason = "not public", issue = "0", feature = "fd")]
+
+use cmp;
+use io::{self, Read};
+use libc::{self, c_int, c_void, ssize_t};
+use mem;
+use sys::cvt;
+use sys_common::AsInner;
+use sys_common::io::read_to_end_uninitialized;
+
+#[derive(Debug)]
+pub struct FileDesc {
+    fd: c_int,
+}
+
+fn max_len() -> usize {
+    // The maximum read limit on most posix-like systems is `SSIZE_MAX`,
+    // with the man page quoting that if the count of bytes to read is
+    // greater than `SSIZE_MAX` the result is "unspecified".
+    //
+    // On OSX, however, apparently the 64-bit libc is either buggy or
+    // intentionally showing odd behavior by rejecting any read with a size
+    // larger than or equal to INT_MAX. To handle both of these the read
+    // size is capped on both platforms.
+    if cfg!(target_os = "macos") {
+        <c_int>::max_value() as usize - 1
+    } else {
+        <ssize_t>::max_value() as usize
+    }
+}
+
+impl FileDesc {
+    pub fn new(fd: c_int) -> FileDesc {
+        FileDesc { fd: fd }
+    }
+
+    pub fn raw(&self) -> c_int { self.fd }
+
+    /// Extracts the actual filedescriptor without closing it.
+    pub fn into_raw(self) -> c_int {
+        let fd = self.fd;
+        mem::forget(self);
+        fd
+    }
+
+    pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::read(self.fd,
+                       buf.as_mut_ptr() as *mut c_void,
+                       cmp::min(buf.len(), max_len()))
+        })?;
+        Ok(ret as usize)
+    }
+
+    pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        let mut me = self;
+        (&mut me).read_to_end(buf)
+    }
+
+    pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
+        unsafe fn cvt_pread64(fd: c_int, buf: *mut c_void, count: usize, offset: i64)
+            -> io::Result<isize>
+        {
+            use libc::pread as pread64;
+            cvt(pread64(fd, buf, count, offset))
+        }
+
+        unsafe {
+            cvt_pread64(self.fd,
+                        buf.as_mut_ptr() as *mut c_void,
+                        cmp::min(buf.len(), max_len()),
+                        offset as i64)
+                .map(|n| n as usize)
+        }
+    }
+
+    pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::write(self.fd,
+                        buf.as_ptr() as *const c_void,
+                        cmp::min(buf.len(), max_len()))
+        })?;
+        Ok(ret as usize)
+    }
+
+    pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
+        unsafe fn cvt_pwrite64(fd: c_int, buf: *const c_void, count: usize, offset: i64)
+            -> io::Result<isize>
+        {
+            use libc::pwrite as pwrite64;
+            cvt(pwrite64(fd, buf, count, offset))
+        }
+
+        unsafe {
+            cvt_pwrite64(self.fd,
+                         buf.as_ptr() as *const c_void,
+                         cmp::min(buf.len(), max_len()),
+                         offset as i64)
+                .map(|n| n as usize)
+        }
+    }
+}
+
+impl<'a> Read for &'a FileDesc {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        unsafe { read_to_end_uninitialized(self, buf) }
+    }
+}
+
+impl AsInner<c_int> for FileDesc {
+    fn as_inner(&self) -> &c_int { &self.fd }
+}
+
+impl Drop for FileDesc {
+    fn drop(&mut self) {
+        // Note that errors are ignored when closing a file descriptor. The
+        // reason for this is that if an error occurs we don't actually know if
+        // the file descriptor was closed or not, and if we retried (for
+        // something like EINTR), we might close another valid file descriptor
+        // (opened after we closed ours.
+        let _ = unsafe { libc::close(self.fd) };
+    }
+}
diff --git a/ctr-std/src/sys/unix/io.rs b/ctr-std/src/sys/unix/io.rs
new file mode 100644
index 0000000..6d38b00
--- /dev/null
+++ b/ctr-std/src/sys/unix/io.rs
@@ -0,0 +1,81 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io;
+use libc;
+use sys::fd::FileDesc;
+
+pub struct Stdin(());
+pub struct Stdout(());
+pub struct Stderr(());
+
+impl Stdin {
+    pub fn new() -> io::Result<Stdin> { Ok(Stdin(())) }
+
+    pub fn read(&self, data: &mut [u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDIN_FILENO);
+        let ret = fd.read(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDIN_FILENO);
+        let ret = fd.read_to_end(buf);
+        fd.into_raw();
+        ret
+    }
+}
+
+impl Stdout {
+    pub fn new() -> io::Result<Stdout> { Ok(Stdout(())) }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDOUT_FILENO);
+        let ret = fd.write(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn flush(&self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Stderr {
+    pub fn new() -> io::Result<Stderr> { Ok(Stderr(())) }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDERR_FILENO);
+        let ret = fd.write(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn flush(&self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+// FIXME: right now this raw stderr handle is used in a few places because
+//        std::io::stderr_raw isn't exposed, but once that's exposed this impl
+//        should go away
+impl io::Write for Stderr {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        Stderr::write(self, data)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Stderr::flush(self)
+    }
+}
+
+pub const EBADF_ERR: i32 = ::libc::EBADF as i32;
+pub const STDIN_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE;
diff --git a/ctr-std/src/sys/unix/mod.rs b/ctr-std/src/sys/unix/mod.rs
index ec657d8..0da1d3b 100644
--- a/ctr-std/src/sys/unix/mod.rs
+++ b/ctr-std/src/sys/unix/mod.rs
@@ -15,6 +15,8 @@ use libc;
 
 pub mod ext;
 pub mod fast_thread_local;
+pub mod fd;
+pub mod stdio;
 pub mod memchr;
 pub mod mutex;
 pub mod os;
diff --git a/ctr-std/src/sys/unix/stdio.rs b/ctr-std/src/sys/unix/stdio.rs
new file mode 100644
index 0000000..6d38b00
--- /dev/null
+++ b/ctr-std/src/sys/unix/stdio.rs
@@ -0,0 +1,81 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io;
+use libc;
+use sys::fd::FileDesc;
+
+pub struct Stdin(());
+pub struct Stdout(());
+pub struct Stderr(());
+
+impl Stdin {
+    pub fn new() -> io::Result<Stdin> { Ok(Stdin(())) }
+
+    pub fn read(&self, data: &mut [u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDIN_FILENO);
+        let ret = fd.read(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDIN_FILENO);
+        let ret = fd.read_to_end(buf);
+        fd.into_raw();
+        ret
+    }
+}
+
+impl Stdout {
+    pub fn new() -> io::Result<Stdout> { Ok(Stdout(())) }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDOUT_FILENO);
+        let ret = fd.write(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn flush(&self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Stderr {
+    pub fn new() -> io::Result<Stderr> { Ok(Stderr(())) }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        let fd = FileDesc::new(libc::STDERR_FILENO);
+        let ret = fd.write(data);
+        fd.into_raw();
+        ret
+    }
+
+    pub fn flush(&self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+// FIXME: right now this raw stderr handle is used in a few places because
+//        std::io::stderr_raw isn't exposed, but once that's exposed this impl
+//        should go away
+impl io::Write for Stderr {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        Stderr::write(self, data)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Stderr::flush(self)
+    }
+}
+
+pub const EBADF_ERR: i32 = ::libc::EBADF as i32;
+pub const STDIN_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE;
diff --git a/ctr-std/src/sys_common/at_exit_imp.rs b/ctr-std/src/sys_common/at_exit_imp.rs
new file mode 100644
index 0000000..ce6fd4c
--- /dev/null
+++ b/ctr-std/src/sys_common/at_exit_imp.rs
@@ -0,0 +1,80 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Implementation of running at_exit routines
+//!
+//! Documentation can be found on the `rt::at_exit` function.
+
+use alloc::boxed::FnBox;
+use ptr;
+use sys_common::mutex::Mutex;
+
+type Queue = Vec<Box<FnBox()>>;
+
+// NB these are specifically not types from `std::sync` as they currently rely
+// on poisoning and this module needs to operate at a lower level than requiring
+// the thread infrastructure to be in place (useful on the borders of
+// initialization/destruction).
+static LOCK: Mutex = Mutex::new();
+static mut QUEUE: *mut Queue = ptr::null_mut();
+
+// The maximum number of times the cleanup routines will be run. While running
+// the at_exit closures new ones may be registered, and this count is the number
+// of times the new closures will be allowed to register successfully. After
+// this number of iterations all new registrations will return `false`.
+const ITERS: usize = 10;
+
+unsafe fn init() -> bool {
+    if QUEUE.is_null() {
+        let state: Box<Queue> = box Vec::new();
+        QUEUE = Box::into_raw(state);
+    } else if QUEUE as usize == 1 {
+        // can't re-init after a cleanup
+        return false
+    }
+
+    true
+}
+
+pub fn cleanup() {
+    for i in 0..ITERS {
+        unsafe {
+            LOCK.lock();
+            let queue = QUEUE;
+            QUEUE = if i == ITERS - 1 {1} else {0} as *mut _;
+            LOCK.unlock();
+
+            // make sure we're not recursively cleaning up
+            assert!(queue as usize != 1);
+
+            // If we never called init, not need to cleanup!
+            if queue as usize != 0 {
+                let queue: Box<Queue> = Box::from_raw(queue);
+                for to_run in *queue {
+                    to_run();
+                }
+            }
+        }
+    }
+}
+
+pub fn push(f: Box<FnBox()>) -> bool {
+    let mut ret = true;
+    unsafe {
+        LOCK.lock();
+        if init() {
+            (*QUEUE).push(f);
+        } else {
+            ret = false;
+        }
+        LOCK.unlock();
+    }
+    ret
+}
diff --git a/ctr-std/src/sys_common/mod.rs b/ctr-std/src/sys_common/mod.rs
index c6f94ed..7aedb69 100644
--- a/ctr-std/src/sys_common/mod.rs
+++ b/ctr-std/src/sys_common/mod.rs
@@ -24,6 +24,7 @@
 
 #![allow(missing_docs)]
 
+pub mod at_exit_imp;
 pub mod io;
 pub mod mutex;
 pub mod poison;
@@ -56,6 +57,20 @@ pub trait FromInner<Inner> {
     fn from_inner(inner: Inner) -> Self;
 }
 
+/// Enqueues a procedure to run when the main thread exits.
+///
+/// Currently these closures are only run once the main *Rust* thread exits.
+/// Once the `at_exit` handlers begin running, more may be enqueued, but not
+/// infinitely so. Eventually a handler registration will be forced to fail.
+///
+/// Returns `Ok` if the handler was successfully registered, meaning that the
+/// closure will be run once the main thread exits. Returns `Err` to indicate
+/// that the closure could not be registered, meaning that it is not scheduled
+/// to be run.
+pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
+    if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
+}
+
 macro_rules! rtabort {
     ($($t:tt)*) => (::sys_common::util::abort(format_args!($($t)*)))
 }