It may happen that the time-zone information in the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation
contains an empty StandardName / DaylightName, or is too long for the
standard maximum 32-character length, and therefore is returned empty.
And/or it may happen as well that some of the standard names (value "Std")
present in some of the time zones listed in
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones
are similarly too long, and therefore are returned as empty strings.
In case this happens, perform comparisons instead with the numerical
values Bias, StandardBias, DaylightBias, StandardDate and DaylightDate
in order to find a match.
It is interesting to note also that in Vista+ there is an additional
REG_SZ value "TimeZoneKeyName" in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation
that allows to directly find a match in the time zones list in
"Windows NT\CurrentVersion\Time Zones".
This small win32 library provides time-zone utility wrappers around
Win32 functions, that are used by different ReactOS modules such as
timedate.cpl, syssetup.dll, and a possible future 'tzutil' tool.
The code has been extracted from the common code found in both
timedate.cpl and syssetup.dll.
- Make sure the DWLP_* values are correct on _WIN64
- Don't use the DWL_* constants, they are not portable. Enforce this by removing them entirely from winuser.h
- Make sure Get/SetWindowLong*Ptr* is used and pointers are not truncated to LONG
