TIME_ZONE_INFORMATION structure (timezoneapi.h)
Specifies settings for a time zone.
Syntax
typedef struct _TIME_ZONE_INFORMATION {
LONG Bias;
WCHAR StandardName[32];
SYSTEMTIME StandardDate;
LONG StandardBias;
WCHAR DaylightName[32];
SYSTEMTIME DaylightDate;
LONG DaylightBias;
} TIME_ZONE_INFORMATION, *PTIME_ZONE_INFORMATION, *LPTIME_ZONE_INFORMATION;
Members
Bias
The current bias for local time translation on this computer, in minutes. 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[32]
A description for standard time. For example, "EST" could indicate Eastern Standard Time. The string will be returned unchanged by the GetTimeZoneInformation function. This string can be empty.
StandardDate
A SYSTEMTIME structure that contains a date and local time when the transition from daylight saving time to standard time occurs on this operating system. If the time zone does not support daylight saving time or if the caller needs to disable daylight saving time, the wMonth member in the SYSTEMTIME structure must be zero. If this date is specified, the DaylightDate member of this structure must also be specified.
Otherwise, the system assumes the time zone data is invalid and no changes will be applied.
To select the correct day in the month, set the wYear member to zero, the wHour and wMinute members to the transition time, the wDayOfWeek member to the appropriate weekday, and the wDay member to indicate the occurrence of the day of the week within the month (1 to 5, where 5 indicates the final occurrence during the month if that day of the week does not occur 5 times).
Using this notation, specify 02:00 on the first Sunday in April as follows: wHour = 2, wMonth = 4, wDayOfWeek = 0, wDay = 1. Specify 02:00 on the last Thursday in October as follows: wHour = 2, wMonth = 10, wDayOfWeek = 4, wDay = 5.
If the wYear member is not zero, the transition date is absolute; it will only occur one time. Otherwise, it is a relative date that occurs yearly.
StandardBias
The 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[32]
A description for daylight saving time. For example, "PDT" could indicate Pacific Daylight Time. The string will be returned unchanged by the GetTimeZoneInformation function. This string can be empty.
DaylightDate
A SYSTEMTIME structure that contains a date and local time when the transition from standard time to daylight saving time occurs on this operating system. If the time zone does not support daylight saving time or if the caller needs to disable daylight saving time, the wMonth member in the SYSTEMTIME structure must be zero. If this date is specified, the StandardDate member in this structure must also be specified.
Otherwise, the system assumes the time zone data is invalid and no changes will be applied.
To select the correct day in the month, set the wYear member to zero, the wHour and wMinute members to the transition time, the wDayOfWeek member to the appropriate weekday, and the wDay member to indicate the occurrence of the day of the week within the month (1 to 5, where 5 indicates the final occurrence during the month if that day of the week does not occur 5 times).
If the wYear member is not zero, the transition date is absolute; it will only occur one time. Otherwise, it is a relative date that occurs yearly.
DaylightBias
The bias value to be used during local time translations that occur during daylight saving 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 saving time. In most time zones, the value of this member is –60.
Remarks
Settings for each time zone are stored in the following registry key:
HKEY_LOCAL_MACHINE SOFTWARE Microsoft Windows NT CurrentVersion Time Zones time_zone_name
Each time zone entry includes the following registry values.
| Registry value | Type | Description |
|---|---|---|
| Display | REG_SZ | The display name. |
| Dlt | REG_SZ | The description for daylight time. |
| MUI_Display | REG_SZ | The display name as a string of the form @path,-stringID[;comment]. For more information, see MUI. |
| MUI_Dlt | REG_SZ | The description for daylight time as a string of the form @path,-stringID[;comment]. |
| MUI_Std | REG_SZ | The description for standard time as a string of the form @path,-stringID[;comment]. |
| Std | REG_SZ | The description for standard time. |
| TZI | REG_BINARY |
The following time zone information.
|
For more information about the Dynamic DST key, see DYNAMIC_TIME_ZONE_INFORMATION.
Both StandardName and DaylightName are localized according to the current user default UI language.
Examples
For an example, see SetTimeZoneInformation.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps | UWP apps] |
| Minimum supported server | Windows 2000 Server [desktop apps | UWP apps] |
| Header | timezoneapi.h (include Windows.h) |