1//! > Polyfill for `is_terminal` stdlib feature for use with older MSRVs
2
3#![cfg_attr(docsrs, feature(doc_auto_cfg))]
4#![warn(clippy::print_stderr)]
5#![warn(clippy::print_stdout)]
6
7/// Trait to determine if a descriptor/handle refers to a terminal/tty.
8pub trait IsTerminal: sealed::Sealed {
9 /// Returns `true` if the descriptor/handle refers to a terminal/tty.
10 ///
11 /// On platforms where Rust does not know how to detect a terminal yet, this will return
12 /// `false`. This will also return `false` if an unexpected error occurred, such as from
13 /// passing an invalid file descriptor.
14 ///
15 /// # Platform-specific behavior
16 ///
17 /// On Windows, in addition to detecting consoles, this currently uses some heuristics to
18 /// detect older msys/cygwin/mingw pseudo-terminals based on device name: devices with names
19 /// starting with `msys-` or `cygwin-` and ending in `-pty` will be considered terminals.
20 /// Note that this [may change in the future][changes].
21 ///
22 /// [changes]: std::io#platform-specific-behavior
23 fn is_terminal(&self) -> bool;
24}
25
26mod sealed {
27 pub trait Sealed {}
28}
29
30macro_rules! impl_is_terminal {
31 ($($t:ty),*$(,)?) => {$(
32 impl sealed::Sealed for $t {}
33
34 impl IsTerminal for $t {
35 #[inline]
36 fn is_terminal(&self) -> bool {
37 std::io::IsTerminal::is_terminal(self)
38 }
39 }
40 )*}
41}
42
43impl_is_terminal!(
44 std::fs::File,
45 std::io::Stdin,
46 std::io::StdinLock<'_>,
47 std::io::Stdout,
48 std::io::StdoutLock<'_>,
49 std::io::Stderr,
50 std::io::StderrLock<'_>
51);
52