The IsStandardAbsoluteDate property retrieves a value that indicates whether StandardDate is an Absolute or Relative date.
StandardDate is the date that the switch from daylight savings time over to standard time occurs, for a particular time zone.
IsStandardAbsoluteDate is undefined if SupportsDST is VARIANT_FALSE.
The VARIANT_BOOL data type (also known as VT_BOOL) uses the value -1 to represent TRUE and 0 to represent FALSE. It is defined in the wtypes.h header file in the following manner:
typedef short VARIANT_BOOL;
A common programming error occurs when, for readability purposes, you want to set a VARIANT_BOOL value to TRUE or FALSE. You can achieve the same effect by using the aliases VARIANT_TRUE and VARIANT_FALSE, which are also defined in the wtypes.h header file.
#define VARIANT_TRUE ((VARIANT_BOOL)0xffff) #define VARIANT_FALSE ((VARIANT_BOOL)0)