gmtime_r, gmtime64_r - convert date and time to UTC (thread-safe)

Syntax	#include <time.h> struct tm *gmtime_r(const time_t * clock, struct tm * result); struct tm *gmtime64_r(const time64_t * clock, struct tm * result);
Description	The functions gmtime_r() and gmtime_r() converts the time (number of seconds since the beginning of the epoch) pointed to by clock to the UTC time (Coordinated Universal Time) in the format described in the struct tm structure. The result is stored in the data area pointed to by result.
Return val.	Address of the structure pointed to by result,
		if successful.
	Null pointer	if an error occurs or if UTC is not available.
See also	gmtime().