Формати дати і часу

Container	Domain	Format / Notes	Min Date	Resolution
SYSTEMTIME	Win32	Struct (16 bytes)	January 1, 1601	1 millisecond
FILETIME	Win32	Offset value (64bit unsigned int)	January 1, 1601	100 nanoseconds
VT_DATE	Win32 / OLE Automation	Offset value (64bit signed float), 0.0 is December 30, 1899.	January 1, 100 (1)	500 milliseconds (2)
FAT/MS-DOS	Win32	Struct (values packed into two 16bit ints)	January 1, 1980	2 seconds
time_t	CRT	Offset value (unsigned int)	January 1, 1970	1 second
tm	CRT	Struct (36 bytes (3))	January 1, 1900	1 second

Перетворення

Windows Times

	SYSTEMTIME	FILETIME	VT_DATE	FAT/приложений-DOS
SYSTEMTIME		SystemTimeToFileTime	SystemTimeToVariantTime
FILETIME	FileTimeToSystemTime			FileTimeToDosDateTime
VT_DATE	VariantTimeToSystemTime			VariantTimeToDosDateTime
FAT/приложений-DOS		DosDateTimeToFileTime	DosDateTimeToVariantTime

CRT Times

	time_t	ТМ
time_t		gmtime
ТМ	mktime

Converting between SYSTEMTIME and time_t

 
void SystemTimeToTime_t(SYSTEMTIME *systemTime, time_t *dosTime) 
{ 
 LARGE_INTEGER jan1970FT = {0}; 
 jan1970FT.QuadPart = 116444736000000000I64; // january 1st 1970 
 LARGE_INTEGER utcFT = {0}; 
 SystemTimeToFileTime(systemTime, (FILETIME*)&utcFT); 
 unsigned __int64 utcDosTime = (utcFT.QuadPart - an1970FT.QuadPart) / 10000000; 
 *dosTime = (time_t)utcDosTime; 
}
void Time_tToSystemTime(time_t dosTime, SYSTEMTIME *systemTime)
{ 
 LARGE_INTEGER jan1970FT = {0}; 
 jan1970FT.QuadPart = 116444736000000000I64; // january 1st 1970
 LARGE_INTEGER utcFT = {0};
 utcFT.QuadPart = ((unsigned __int64)dosTime) * 10000000 + jan1970FT.QuadPart; 
 FileTimeToSystemTime((FILETIME*)&utcFT, systemTime);
}