CANTMASK1
t->t_hold.__sigbits[1] = FILLSET1 & ~CANTMASK1;
#define MASKSET1 (FILLSET1 & ~CANTMASK1)
set.__sigbits[1] = FILLSET1 & ~CANTMASK1;
t->t_hold.__sigbits[1] = FILLSET1 & ~CANTMASK1;
#if (CANTMASK1 == 0 && CANTMASK2 == 0)
{CANTMASK0, CANTMASK1, CANTMASK2};
(ks)->__sigbits[1] = (us)->__sigbits[1] & (FILLSET1 & ~CANTMASK1), \
bits1 &= (FILLSET1 & ~CANTMASK1);