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Active Forums => QB64 Discussion => Topic started by: SpriggsySpriggs on July 19, 2020, 12:53:48 pm

Title: Function to convert UTC to local time?
Post by: SpriggsySpriggs on July 19, 2020, 12:53:48 pm
Does anyone happen to have a function handy for converting UTC to local time? I've found several things online for C/C++ but they always fail to compile. I'd like to be able to take a UTC timestamp and just put it into whatever time zone is passed.
Title: Re: Function to convert UTC to local time?
Post by: Dav on July 19, 2020, 01:18:47 pm
Is this something like you're looking for?
https://www.qb64.org/forum/index.php?topic=1638.30 (https://www.qb64.org/forum/index.php?topic=1638.30)

- Dav
Title: Re: Function to convert UTC to local time?
Post by: moises1953 on July 19, 2020, 01:22:31 pm
Have you tested this?
https://docs.microsoft.com/es-es/windows/win32/api/timezoneapi/nf-timezoneapi-systemtimetotzspecificlocaltimeex

Title: Re: Function to convert UTC to local time?
Post by: SpriggsySpriggs on July 19, 2020, 01:23:27 pm
Quote from: moises1953 on July 19, 2020, 01:22:31 pm
Have you tested this?
https://docs.microsoft.com/es-es/windows/win32/api/timezoneapi/nf-timezoneapi-systemtimetotzspecificlocaltimeex
@moises1953
I've looked at it but I can't find good information on how to pass the timestamp I have to it.
Title: Re: Function to convert UTC to local time?
Post by: SpriggsySpriggs on July 19, 2020, 01:25:12 pm
Quote from: Dav on July 19, 2020, 01:18:47 pm
Is this something like you're looking for?
https://www.qb64.org/forum/index.php?topic=1638.30 (https://www.qb64.org/forum/index.php?topic=1638.30)
@Dav I saw that but it look like it just converts a timestamp to Epoch/UNIX time which I already have. I'm just wanting to take a string of a UTC date and time and make it local time. Using SystemTimeToTzSpecificLocalTime as moises suggested would probably be it but I can't figure out how to go about using it.
Title: Re: Function to convert UTC to local time?
Post by: moises1953 on July 19, 2020, 03:12:57 pm
May be this code helps you

Code: QB64: [Select]
  1. TYPE SystemTime
  2.   wYear AS INTEGER
  3.   wMonth AS INTEGER
  4.   wDayOfWeek AS INTEGER
  5.   wDay AS INTEGER
  6.   wHour AS INTEGER
  7.   wMinute AS INTEGER
  8.   wSecond AS INTEGER
  9.   wMilliseconds AS INTEGER
  11.  
  12. TYPE TDZoneInfo 'TIME_DYNAMIC_ZONE_INFORMATION
  13.   Bias AS LONG
  14.   StandardName AS STRING * 64 'wchar32
  15.   StandardDate AS SystemTime
  16.   StandardBias AS LONG
  17.   DaylightName AS STRING * 64 'wchar32
  18.   DaylightDate AS SystemTime
  19.   DaylightBias AS LONG
  20.   TimeZoneKeyName AS STRING * 256 ' WCHAR128
  21.   DynamicDaylightTimeDisabled AS _BYTE 'BOOLEAN->BYTE
  23.  
  25.   FUNCTION SystemTimeToTzSpecificLocalTimeEx%% (BYVAL lpTimeZoneInformation AS _UNSIGNED _OFFSET,_
  26.     BYVAL lpUniversalTime AS _UNSIGNED _OFFSET, byval lpLocalTime AS _UNSIGNED _OFFSET)
  27.   FUNCTION GetDynamicTimeZoneInformation~& (BYVAL lpTimeZoneInformation AS _UNSIGNED _OFFSET)
  28.   SUB GetSystemTime (BYVAL lpSystemTime AS _UNSIGNED _OFFSET)
  30.  
  31. DIM UTCTime AS SystemTime, loctime AS SystemTime, ZoneInfo AS TDZoneInfo
  32.  
  33. CALL GetSystemTime(_OFFSET(UTCTime))
  34.  
  35. PRINT UTCTime.wYear; "/"; UTCTime.wMonth; "/"; UTCTime.wDay
  36. PRINT UTCTime.wHour; ":"; UTCTime.wMinute; ":"; UTCTime.wSecond
  37.  
  38. e~& = GetDynamicTimeZoneInformation(_OFFSET(ZoneInfo))
  39. PRINT ZoneInfo.StandardName
  40.  
  41. f%% = SystemTimeToTzSpecificLocalTimeEx(_OFFSET(ZoneInfo), _OFFSET(UTCTime), _OFFSET(loctime))
  42.  
  43. PRINT loctime.wYear; "/"; loctime.wMonth; "/"; loctime.wDay
  44. PRINT loctime.wHour; ":"; loctime.wMinute; ":"; loctime.wSecond
  45.  
  47.  
Title: Re: Function to convert UTC to local time?
Post by: SpriggsySpriggs on July 19, 2020, 05:08:13 pm
@moises1953 That is exactly what I need! Thank you so much!
In the meantime, I discovered how to implement Javascript in QB64 using NodeJS! I'll make a full post on how to do that soon. Here is what my solution was for getting the correct date:
Code: QB64: [Select]
  1.     DIM JS AS INTEGER
  2.     JS = FREEFILE
  3.     OPEN "uuiddate.js" FOR OUTPUT AS #JS
  4.     PRINT #JS, "const fs = require('fs');"
  5.     PRINT #JS, "let writeStream = fs.createWriteStream('uuiddate.d');"
  6.     PRINT #JS, "var d = new Date('" + uuiddate(timestamp) + " " + hour + ":" + minute + ":" + second + " UTC');"
  7.     PRINT #JS, "writeStream.write(d.toLocaleString().replace(',',''),'ascii');"
  8.     PRINT #JS, "writeStream.end();"
  9.     CLOSE #JS
  10.     SHELL _HIDE "node " + CHR$(34) + _STARTDIR$ + "\uuiddate.js" + CHR$(34)
  11.     KILL "uuiddate.js"
  12.     DIM d AS INTEGER
  13.     d = FREEFILE
  14.     DIM utctolocale AS STRING
  15.     OPEN "uuiddate.d" FOR BINARY AS #d
  16.     IF LOF(d) <> 0 THEN
  17.         LINE INPUT #d, utctolocale
  18.     END IF
  19.     CLOSE #d
  20.     KILL "uuiddate.d"
  21.     ExtractTimestamp = utctolocale
Title: Re: Function to convert UTC to local time?
Post by: moises1953 on July 23, 2020, 01:01:40 pm
This is a more compact form

Code: QB64: [Select]
  1. TYPE SystemTime
  2.   wYear AS INTEGER
  3.   wMonth AS INTEGER
  4.   wDayOfWeek AS INTEGER
  5.   wDay AS INTEGER
  6.   wHour AS INTEGER
  7.   wMinute AS INTEGER
  8.   wSecond AS INTEGER
  9.   wMilliseconds AS INTEGER
  11.  
  12. TYPE TDZoneInfo 'TIME_DYNAMIC_ZONE_INFORMATION
  13.   Bias AS LONG
  14.   StandardName AS STRING * 64 'wchar32
  15.   StandardDate AS SystemTime
  16.   StandardBias AS LONG
  17.   DaylightName AS STRING * 64 'wchar32
  18.   DaylightDate AS SystemTime
  19.   DaylightBias AS LONG
  20.   TimeZoneKeyName AS STRING * 256 ' WCHAR128
  21.   DynamicDaylightTimeDisabled AS _BYTE 'BOOLEAN->BYTE
  23.  
  25.   FUNCTION SystemTimeToTzSpecificLocalTimeEx%% (lpTimeZoneInformation AS tdzoneinfo,_
  26.     lpUniversalTime AS systemTime, lpLocalTime AS systemTime)
  27.   FUNCTION GetDynamicTimeZoneInformation~& (lpTimeZoneInformation AS TDZoneInfo)
  28.   SUB GetSystemTime (lpSystemTime AS SystemTime)
  30.  
  31. DIM UTCTime AS SystemTime, loctime AS SystemTime, ZoneInfo AS TDZoneInfo
  32.  
  33. CALL GetSystemTime(UTCTime)
  34.  
  35. PRINT UTCTime.wYear; "/"; UTCTime.wMonth; "/"; UTCTime.wDay
  36. PRINT UTCTime.wHour; ":"; UTCTime.wMinute; ":"; UTCTime.wSecond
  37.  
  38. e~& = GetDynamicTimeZoneInformation(ZoneInfo)
  39. PRINT ZoneInfo.StandardName
  40.  
  41. f%% = SystemTimeToTzSpecificLocalTimeEx(ZoneInfo, UTCTime, loctime)
  42.  
  43. PRINT loctime.wYear; "/"; loctime.wMonth; "/"; loctime.wDay
  44. PRINT loctime.wHour; ":"; loctime.wMinute; ":"; loctime.wSecond
  45.  
  47.  
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