How to Use Panic Handlers in no_std Rust

You define a panic handler in no_std Rust by creating a function with the #[panic_handler] attribute that takes a &core::panic::PanicInfo and returns ! (never returns). This function replaces the default panic behavior, which is unavailable in no_std environments, allowing you to handle unrecoverable errors like aborting or logging.

#![no_std]
#![no_main]

#[panic_handler]
fn panic_handler(info: &core::panic::PanicInfo) -> ! {
    // Custom logic here, e.g., logging or hardware reset
    loop {}
}

In no_std Rust, the standard library isn't available to automatically handle crashes. You must write your own function to decide what happens when the program hits a fatal error, like stopping execution or resetting the device.