Macro custom_print::define_panic_hook

macro_rules! define_panic_hook {
    ( $(#[$extern_meta:meta])* $vis:vis fn $name:ident(...), $($args:tt)* ) => { ... };
    ( $($args:tt)* ) => { ... };
}

Defines panic_hook function that can be used as panic hook that uses the specified writer.

The first argument specify function name in the format fn FUNC_NAME(...) and can be omitted to use the default name panic_hook.

Examples

use once_cell::sync::Lazy;
use std::sync::Mutex;

static MESSAGE: Lazy<Mutex<String>> = Lazy::new(Mutex::default);

fn main() {
    use std::panic::{catch_unwind, take_hook};

    fn write(value: &str) {
        let mut chunks = MESSAGE.lock().unwrap();
        *chunks += value;
    }

    custom_print::define_panic_hook!(concat, write);
    std::panic::set_hook(Box::new(panic_hook));

    let result = catch_unwind(|| assert_eq!("foo", "bar"));
    let _ = take_hook();
    assert!(result.is_err());
    let message = MESSAGE.lock().unwrap();

    assert!(message.contains("panicked"));
    assert!(message.contains("assertion failed"));
    assert!(message.contains("\"foo\""));
    assert!(message.contains("\"bar\""));
}