Function inject_poweroff_handler 

pub fn inject_poweroff_handler(handler: fn(ExitCode))

Injects a handler that can power off the system.

If no handler is injected, poweroff calls crate::arch::power::try_poweroff. Injection replaces that behavior: poweroff invokes only the injected handler, which may call the architecture-specific operation as part of its own policy.

use ostd::power::{self, ExitCode};

fn init() {
    power::inject_poweroff_handler(poweroff_policy);
}

fn poweroff_policy(code: ExitCode) {
    try_platform_poweroff();
    ostd::arch::power::try_poweroff(code);
}

fn try_platform_poweroff() {
    // Try a platform-specific poweroff mechanism, if available.
}

The function may be called only once; subsequent calls take no effect.