This function sets the current time-zone parameters. These parameters control translations from UTC to local time.
Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.
SetTimeZoneInformation does not change the clock and therefore will not affect subsequent calls to GetLocalTime. SetTimeZoneInformation only affects subsequent calls to GetSystemTime. SetTimeZoneInformation does not save the newly written data into the persistent registry. To write the data permanently, you need to make the following call: RegFlushKey(HKEY_LOCAL_MACHINE). For more information, see RegFlushKey.
All translations between UTC and local time are based on the following formula:
UTC = local time + bias
The bias is the difference, in minutes, between UTC and local time.