safe_level

/*
 *  call-seq:
 *     thr.safe_level   => integer
 *  
 *  Returns the safe level in effect for <i>thr</i>. Setting thread-local safe
 *  levels can help when implementing sandboxes which run insecure code.
 *     
 *     thr = Thread.new { $SAFE = 3; sleep }
 *     Thread.current.safe_level   #=> 0
 *     thr.safe_level              #=> 3
 */

static VALUE
rb_thread_safe_level(thread)
    VALUE thread;
{
    rb_thread_t th;

    th = rb_thread_check(thread);
    if (th == curr_thread) {
        return INT2NUM(ruby_safe_level);
    }
    return INT2NUM(th->safe);
}