int
ymd2yd(
int y,
int m,
int d)
{
/*
* convert y/m/d to elapsed calendar units, convert that to
* elapsed days since the start of the given year and convert
* back to unity-based day in year.
*
* This does no further error checking, since the underlying
* function is assumed to work out how to handle the data.
*/
return ntpcal_edate_to_yeardays(y-1, m-1, d-1) + 1;
}