PowerBuilder UTC to Local Time Zone Conversion

Received a question about how to convert UTC time to a local time zone.  Finding no PowerBuilder specific references for it, created a sample:



Local External Functions:

Function ulong GetTimeZoneInformation 
     (ref TIME_ZONE_INFORMATION lpTimeZoneInformation) 
     Library "kernel32"
Function boolean SystemTimeToTzSpecificLocalTime
     (TIME_ZONE_INFORMATION lpTimeZone, SYSTEMTIME lpUniversalTime,
      ref SYSTEMTIME lpLocalTime ) Library "kernel32"

Instance variables:

Constant ulong TIME_ZONE_ID_INVALID  = 4294967295
Constant long TIME_ZONE_ID_STANDARD = 1
Constant long TIME_ZONE_ID_UNKNOWN = 0
Constant long TIME_ZONE_ID_DAYLIGHT = 2

We also need a couple of structures defined for those local external function calls:

global type systemtime from structure
	integer		wYear
	integer		wMonth
	integer		wDayofWeek
	integer		wDay
	integer		wHour
	integer		wMinute
	integer		wSecond
	integer		wMilliseconds
end type

global type time_zone_information from structure
	long		bias
	integer		standardname[31]
	systemtime		standarddate
	long		standardbias
	integer		daylightname[31]
	systemtime		daylightdate
	long		daylightbias
end type

Function (takes UTC datetime as argument, returns datetime converted to local time zone):

TIME_ZONE_INFORMATION tzi
SYSTEMTIME utc
SYSTEMTIME pst
ulong rc
boolean	rc2

//Get's local time zone
rc = GetTimeZoneInformation(tzi)

//Convert PowerBuilder datetime to SYSTEMTIME for UTC
UTC.wYear = Year(Date(a_utc))
UTC.wMonth = Month(Date(a_utc))
UTC.wDay = Day(Date(a_utc))
UTC.wHour = Hour(Time(a_utc))
UTC.wMinute = Minute(Time(a_utc))
UTC.wSecond = Second(Time(a_utc))
UTC.wMilliseconds = 0

//Convert to local time zone
rc2 = SystemTimeToTzSpecificLocalTime(tzi, UTC, pst)

//Convert SYSTEMTIME to PowerBuilder datetime
Return DateTime ( Date ( pst.wYear, pst.wMonth, pst.wDay ), 
     Time ( pst.wHour, pst.wMinute, pst.wSecond ) )