Convert time_t from localtime zone to UTC

Question

I have a time_t that represents the time in seconds since epoch. Those seconds refer to the local time.

I want to convert them to UTC.

Is there

Answer 1

You can use gmtime:

Convert time_t to tm as UTC time Uses the value pointed by timer to fill a tm structure with the values that represent the corresponding time, expressed as a UTC time (i.e., the time at the GMT timezone).

(c) http://www.cplusplus.com/reference/ctime/gmtime/