cppreference.com > Standard C Date & Time > gmtime gmtime Syntax:
      #include <time.h>
      struct tm *gmtime( const time_t *time );
The gmtime() function returns the given time in Coordinated Universal Time (usually Greenwich mean time), unless it's not supported by the system, in which case NULL is returned. Watch out for static return. Related topics: asctime ctime difftime localtime mktime strftime time