Converting from any local time to UTC

To convert the local time of a non-system time zone to UTC, use CTzConverter::ConvertToUniversalTime() , specifying the time zone to convert from:

        TInt errCode = myConverter->ConvertToUniversalTime(myTime, myZoneId);

These time conversions internally do the following:

fetch a number of 'actualized' rules applicable to the years around the supplied time and zone, where an 'actualized' rule defines a single and specific time of year when local time changes. It is derived from the encoded day rule defined in the Olson’s TZ database RULE.
cache these rules for subsequent use.
identify which rule immediately precedes the time supplied.
apply the appropriate offsets defined by this rule.

Parent topic: Converting between UTC and local time