How do I get keyboard input without the user pressing the Enter key?

Question

I would use ncurses but I want it to run on Windows. In C++, I could use kbhit() and getch() from conio to first check if a character was pressed, then get it.

I would like something similar in Rust.

Answer 1

With the crate device_query you can query the keyboard state without requiring an active window. You just need to add in your Cargo.toml file the dependency to this crate:

[dependencies]
device_query = "0.1.0"

The usage is straightforward and similar to kbhit() and getch(). The difference is you'll receive a Vec of pressed keys (Keycode) and this Vec will be empty if no key is pressed. A single call covers the functionality of both kbhit() and getch() combined.

use device_query::{DeviceQuery, DeviceState, Keycode};

fn main() {
    let device_state = DeviceState::new();
    loop {
        let keys: Vec<Keycode> = device_state.get_keys();
        for key in keys.iter() {
            println!("Pressed key: {:?}", key);
        }
    }
}

This program will print out all pressed keys on the console. To instead just check if any key is pressed (like with kbhit() only), you could use is_empty() on the returned Vec<> like this:

let keys: Vec<Keycode> = device_state.get_keys();
if !keys.is_empty(){
    println!("kbhit");
}

Answer 2

You still can do something like

extern {
    fn _getch() -> core::ffi::c_char;
}

fn getch() -> char {
    unsafe {
        _getch() as char
    }
}