__sigmask13
*set &= ~__sigmask13(signo);
return ((*set & __sigmask13(signo)) != 0);
*set |= __sigmask13(signo);
#define __sigaddset13(s, n) (*(s) |= __sigmask13(n))
#define __sigdelset13(s, n) (*(s) &= ~__sigmask13(n))
#define __sigismember13(s, n) (*(s) & __sigmask13(n))