Getting a Timezone name from a GMT offset

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Hi All

Is there any API in C++ which can convert the GMT/UTC offsets to TimeZone names?

Thanks in advance.

e.g. -5 = Eastern Time

Posted 12-Feb-12 21:52pm

SelvaKr

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Bernhard Hiller 13-Feb-12 4:23am

There can be several names for one offset - while the other way round is unique.

2 solutions

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Dhol Gaurav · Answer 1 · 2012-02-12T23:07:00

hello

you can get time zone value from the below code

C++

TIME_ZONE_INFORMATION tz = {0};
STimeZoneFromRegistry binary_data;
DWORD size = sizeof(binary_data);
HKEY hk = NULL;
TCHAR zone_key[] = _T("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones\\Central Standard Time");
if ((RegOpenKeyEx(HKEY_LOCAL_MACHINE, zone_key, 0, KEY_QUERY_VALUE, &hk) == ERROR_SUCCESS) &&
 (RegQueryValueEx(hk, "TZI", NULL, NULL, (BYTE *) &binary_data, &size) == ERROR_SUCCESS))
{
 tz.Bias = binary_data.Bias;
 tz.DaylightBias = binary_data.DaylightBias;
 tz.DaylightDate = binary_data.DaylightDate;
 tz.StandardBias = binary_data.StandardBias;
 tz.StandardDate = binary_data.StandardDate;
}

struct STimeZoneFromRegistry
{
 long  Bias;
 long  StandardBias;
 long  DaylightBias;
 SYSTEMTIME StandardDate;
 SYSTEMTIME DaylightDate;
};

SelvaKr · Answer 2 · 2012-02-13T02:35:00

Solution 2

Hi Gourav

Thanks.

But my requirement is a little different. Just by having the GMT offset, i need to get the Time zone name. Iterating all keys available in the registry to check the offset might help in mapping the name.

Instead i hardcoded the mapping for all time zones from registry and retrieved what i require at runtime.

Thanks again.

Posted 13-Feb-12 2:35am

SelvaKr

Comments

Richard MacCutchan 13-Feb-12 11:02am

But how do you know you got the right one, since they are different depending on which location they apply to? For example, UTC+4 could be Abu Dhabi, Baku, Moscow, Port Moresby etc, all in different countries.