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;
Members
Bias
Specifies the current bias, in minutes, for local time translation on this computer. The bias is the difference, in minutes, between Coordinated Universal Time (UTC) and local time. All translations between UTC and local time are based on the following formula:
UTC = local time + bias
This member is required.
StandardName
Specifies a null-terminated string associated with standard time on this operating system. For example, this parameter could contain "EST" to indicate Eastern Standard Time. This string is not used by the operating system, so anything stored there by using the SetTimeZoneInformation function is returned unchanged by the GetTimeZoneInformation function. This string can be empty.
StandardDate
Specifies a SYSTEMTIME structure that contains a date and UTC when the transition from daylight time to standard time occurs on this operating system. If this date is not specified, the wMonth member in the SYSTEMTIME structure must be zero. If this date is specified, the DaylightDate value in the TIME_ZONE_INFORMATION structure must also be specified. Local time translations done during the standard-time range are relative to the supplied StandardBias value.
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").
StandardBias
Specifies a bias value to be used during local time translations that occur during standard time. This member is ignored if a value for the StandardDate member is not supplied.
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.
DaylightName
Specifies a null-terminated string associated with daylight time on this operating system. For example, this parameter could contain "PDT" to indicate Pacific Daylight Time. This string is not used by the operating system, so anything stored there by using the SetTimeZoneInformation function is returned unchanged by the GetTimeZoneInformation function. This string can be empty.
DaylightDate
Specifies a SYSTEMTIME structure that contains a date and UTC when the transition from standard time to daylight time occurs on this operating system. If this date is not specified, the wMonth member in the SYSTEMTIME structure must be zero. If this date is specified, the StandardDate value in the TIME_ZONE_INFORMATION structure must also be specified. Local time translations during the daylight-time range are relative to the supplied DaylightBias value. This member supports the absolute and day-in-month time formats described for the StandardDate member.
DaylightBias
Specifies a bias value to be used during local time translations that occur during daylight time. This member is ignored if a value for the DaylightDate member is not supplied.
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.
See Also