An application sends a ZGM_GETJDATE message to get the julian date of a date represented as a null-terminated string.
ZGM_GETJDATE wParam = 0; //not used; must be 0 lParam = (LPARAM) lpszString; //pointer to string representation of a date
Valid dates are in the range from 'Jan 1, 1600' to 'Dec 31, 9999'
If the date string represented in lParam is a valid date, the message will return the julian date of the text represented date. If the date string cannot be deciphered to a valid date, the message will return 0.
Julian dates are valid through the range of [1..3068037]. Julian date 1 = 'Jan 1, 1600'. Julian date 3068037 = 'Dec 31, 9999'.