use prelude::v1::*;
use io::prelude::*;
+use cell::RefCell;
use cmp;
use fmt;
use io::lazy::Lazy;
use sync::{Arc, Mutex, MutexGuard};
use sys::stdio;
+/// 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
fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
}
-/// Resets the task-local stdout handle to the specified writer
+/// Resets the task-local stderr handle to the specified writer
///
-/// This will replace the current task's stdout handle, returning the old
-/// handle. All future calls to `print` and friends will emit their output to
+/// This will replace the current task'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 tasks; the default
-/// output handle is to the process's stdout stream.
-#[unstable(feature = "set_panic",
+/// 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")]
#[doc(hidden)]
Some(s)
})
}
+
+/// Resets the task-local stdout handle to the specified writer
+///
+/// This will replace the current task'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 tasks; 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")]
+#[doc(hidden)]
+pub fn set_print(sink: Box<Write + Send>) -> Option<Box<Write + Send>> {
+ use mem;
+ LOCAL_STDOUT.with(move |slot| {
+ mem::replace(&mut *slot.borrow_mut(), Some(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")]
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+ if let Err(e) = LOCAL_STDOUT.with(|s| match s.borrow_mut().as_mut() {
+ Some(w) => w.write_fmt(args),
+ None => stdout().write_fmt(args)
+ }) {
+ panic!("failed printing to stdout: {}", e);
+ }
+}