use syscall_intercept::*;

extern "C" fn hook(
    num: isize,
    a0: isize,
    a1: isize,
    a2: isize,
    a3: isize,
    a4: isize,
    a5: isize,
    result: &mut isize,
) -> InterceptResult {
    ...
}

unsafe { set_hook_fn(hook) };
unsafe { unset_hook_fn() };

let ret = unsafe { syscall_no_intercept(libc::SYS_exit as _, 0) };