DTDateStringsDifference

Returns the difference in days of the first date & time string to the second date & time string.

DTDateStringsDifference PROTO lpszDateTimeString1:QWORD, lpszDateTimeString2:QWORD, DateFormat:QWORD

Parameters

lpszDateTimeString1 - Pointer to a buffer containing the first date & time string. The format of the date & time string is determined by the DateFormat parameter.
lpszDateTimeString2 - Pointer to a buffer containing the second date & time string. The format of the date & time string is determined by the DateFormat parameter.
DateFormat - Value indicating the date & time format used in the buffer pointed to by both the lpszDateTimeString1 parameter and the lpszDateTimeString2 parameter. The parameter can contain one of the following constants as listed in the DateTime Formats page and as defined in the DateTime.inc include file.

Returns

On return RAX contains the difference between the two dates in days as an integer, either positive or negative.

Notes

The date & time string pointed to by the lpszDateTimeString1 parameter is compared against the date & time string pointed to by the lpszDateTimeString2 parameter to determine the difference of the dates.

Both dates are converted to Julian date format internally before comparing the days difference between dates.

If a date & time string contains time information this will be ignored.

Example

.data
CurrentDateTime db DATETIME_STRING dup (0)
SomeOtherDateTime db "2008/03/21",0

.data?
DayDifference dq ?

.code
Invoke DTGetDateTime, Addr CurrentDateTime, CCYYMMDD
Invoke DTDateStringsDifference, Addr CurrentDateTime, Addr SomeOtherDateTime, CCYYMMDD
mov DayDifference, rax ; save day difference to data variable

.IF rax == 0
     ; No difference in dates, do something...
.ELSE
     ; Day difference is - or +, do something else...
.ENDIF