CANTMASK0
t->t_hold.__sigbits[0] = FILLSET0 & ~CANTMASK0;
#define MASKSET0 (FILLSET0 & ~CANTMASK0)
set.__sigbits[0] = FILLSET0 & ~CANTMASK0;
t->t_hold.__sigbits[0] = FILLSET0 & ~CANTMASK0;
CANTMASK0);
{CANTMASK0, CANTMASK1, CANTMASK2};
((ks)->__sigbits[0] = (us)->__sigbits[0] & (FILLSET0 & ~CANTMASK0), \
bits0 &= (FILLSET0 & ~CANTMASK0);