1 //! Making it a little more convenient and safe to query whether
2 //! something is a terminal teletype or not.
3 //! This module defines the IsTty trait and the is_tty method to
4 //! return true if the item represents a terminal.
5 
6 #[cfg(unix)]
7 use std::os::unix::io::AsRawFd;
8 #[cfg(windows)]
9 use std::os::windows::io::AsRawHandle;
10 #[cfg(windows)]
11 use winapi::um::consoleapi::GetConsoleMode;
12 
13 /// Adds the `is_tty` method to types that might represent a terminal
14 ///
15 /// ```rust
16 /// use std::io::stdout;
17 /// use crossterm::tty::IsTty;
18 ///
19 /// let is_tty: bool = stdout().is_tty();
20 /// ```
21 pub trait IsTty {
22     /// Returns true when an instance is a terminal teletype, otherwise false.
is_tty(&self) -> bool23     fn is_tty(&self) -> bool;
24 }
25 
26 /// On unix, the `isatty()` function returns true if a file
27 /// descriptor is a terminal.
28 #[cfg(unix)]
29 impl<S: AsRawFd> IsTty for S {
is_tty(&self) -> bool30     fn is_tty(&self) -> bool {
31         let fd = self.as_raw_fd();
32         unsafe { libc::isatty(fd) == 1 }
33     }
34 }
35 
36 /// On windows, `GetConsoleMode` will return true if we are in a terminal.
37 /// Otherwise false.
38 #[cfg(windows)]
39 impl<S: AsRawHandle> IsTty for S {
is_tty(&self) -> bool40     fn is_tty(&self) -> bool {
41         let mut mode = 0;
42         let ok = unsafe { GetConsoleMode(self.as_raw_handle() as *mut _, &mut mode) };
43         ok == 1
44     }
45 }
46