Use the OnGetMonthInfo event to initialize the display properties of a month. In particular, OnGetMonthInfo allows applications to bold individual days in the calendar (such as holidays). 

To specify that specific dates are to be bolded, use the BoldDays method to obtain a value that can be returned as the MonthBoldInfo parameter. For example, to bold the first and eighth days of every month that is displayed, call

BoldDays([1,8], MonthBoldInfo);

unsigned bolddays[2] = {1,2};
BoldDays(bolddays, MonthBoldInfo);

from the OnGetMonthInfo event handler. 

BoldDays