The TIME_ZONE_INFORMATION structure specifies information specific to the time zone.
typedef struct _TIME_ZONE_INFORMATION { // tzi LONG Bias; WCHAR StandardName[ 32 ]; SYSTEMTIME StandardDate; LONG StandardBias; WCHAR DaylightName[ 32 ]; SYSTEMTIME DaylightDate; LONG DaylightBias; } TIME_ZONE_INFORMATION;
UTC = local time + bias
This member is required.
This member supports two date formats. Absolute format specifies an exact date and time when standard time begins. In this form, the wYear, wMonth, wDay, wHour, wMinute, wSecond, and wMilliseconds members of the SYSTEMTIME structure are used to specify an exact date.
Day-in-month format is specified by setting the wYear member to zero,
setting the wDayOfWeek member to an appropriate weekday, and using a wDay
value in the range 1 through 5 to select the correct day in the month. Using
this notation, the first Sunday in April can be specified, as can the last
Thursday in October (5 is equal to “the last”).
This value is added to the value of the Bias member to form the bias
used during standard time. In most time zones, the value of this member is
zero.
This value is added to the value of the Bias member to form the bias used during daylight time. In most time zones, the value of this member is - 60.