ndaysj
int ndaysj(struct date *_dt);
dn = ndaysj(&dt);
if (nswitch < ndaysj(d))
return (ndaysj(d));
if (nswitchb < ndaysj(d))
return (ndaysj(d));
nswitch = ndaysj(&dftswitch->dt);
nswitch = ndaysj(&p->dt);
nswitchb = ndaysj(&ukswitch);
nswitch = ndaysj(&never);
nswitch = ndaysj(&(p->dt));