__libc_sigaction_slot
usa = __libc_sigaction_slot(sig);
usa = __libc_sigaction_slot(sig);
usa = __libc_sigaction_slot(sig);
_thr_rwl_rdlock(&__libc_sigaction_slot(i)->lock);
_thr_rwl_unlock(&__libc_sigaction_slot(i)->lock);
bzero(&__libc_sigaction_slot(i) -> lock,
usa = __libc_sigaction_slot(sig);