use crate::cell::{Cell, RefCell};
use crate::fmt;
+use crate::fs::File;
use crate::io::{self, BufReader, IoSlice, IoSliceMut, LineWriter, Lines};
use crate::sync::atomic::{AtomicBool, Ordering};
use crate::sync::{Arc, Mutex, MutexGuard, OnceLock};
let _ = stderr().write_fmt(args);
}
+/// Trait to determine if a descriptor/handle refers to a terminal/tty.
+#[unstable(feature = "is_terminal", issue = "98070")]
+pub trait IsTerminal: crate::sealed::Sealed {
+ /// Returns `true` if the descriptor/handle refers to a terminal/tty.
+ ///
+ /// On platforms where Rust does not know how to detect a terminal yet, this will return
+ /// `false`. This will also return `false` if an unexpected error occurred, such as from
+ /// passing an invalid file descriptor.
+ fn is_terminal(&self) -> bool;
+}
+
+macro_rules! impl_is_terminal {
+ ($($t:ty),*$(,)?) => {$(
+ #[unstable(feature = "sealed", issue = "none")]
+ impl crate::sealed::Sealed for $t {}
+
+ #[unstable(feature = "is_terminal", issue = "98070")]
+ impl IsTerminal for $t {
+ #[inline]
+ fn is_terminal(&self) -> bool {
+ crate::sys::io::is_terminal(self)
+ }
+ }
+ )*}
+}
+
+impl_is_terminal!(File, Stdin, StdinLock<'_>, Stdout, StdoutLock<'_>, Stderr, StderrLock<'_>);
+
#[unstable(
feature = "print_internals",
reason = "implementation detail which may disappear or be replaced at any time",