std::panic!

macro_rules! panic {
    () => ({
        panic!("explicit panic")
    });
    ($msg:expr) => ({
        $crate::rt::begin_unwind($msg, {
            // static requires less code at runtime, more constant data
            static _FILE_LINE: (&'static str, usize) = (file!(), line!());
            &_FILE_LINE
        })
    });
    ($fmt:expr, $($arg:tt)+) => ({
        $crate::rt::begin_unwind_fmt(format_args!($fmt, $($arg)+), {
            // The leading _'s are to avoid dead code warnings if this is
            // used inside a dead function. Just `#[allow(dead_code)]` is
            // insufficient, since the user may have
            // `#[forbid(dead_code)]` and which cannot be overridden.
            static _FILE_LINE: (&'static str, usize) = (file!(), line!());
            &_FILE_LINE
        })
    });
}

The entry point for panic of Rust tasks.

This macro is used to inject panic into a Rust task, causing the task to unwind and panic entirely. Each task's panic can be reaped as the Box<Any> type, and the single-argument form of the panic! macro will be the value which is transmitted.

The multi-argument form of this macro panics with a string and has the format! syntax for building a string.

Example

fn main() { #![allow(unreachable_code)] panic!(); panic!("this is a terrible mistake!"); panic!(4); // panic with the value of 4 to be collected elsewhere panic!("this is a {} {message}", "fancy", message = "message"); }

panic!();
panic!("this is a terrible mistake!");
panic!(4); // panic with the value of 4 to be collected elsewhere
panic!("this is a {} {message}", "fancy", message = "message");