windows-nt/Source/XPSP1/NT/base/crts/crtw32/time/time64.c

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2020-09-26 03:20:57 -05:00
/***
*time64.c - get current system time
*
* Copyright (c) 1998-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _time64() - gets the current system time and converts it to
* internal (__time64_t) format time.
*
*Revision History:
* 05-20-98 GJF Created.
*
*******************************************************************************/
#include <cruntime.h>
#include <time.h>
#include <internal.h>
#include <windows.h>
/*
* Number of 100 nanosecond units from 1/1/1601 to 1/1/1970
*/
#define EPOCH_BIAS 116444736000000000i64
/*
* Union to facilitate converting from FILETIME to unsigned __int64
*/
typedef union {
unsigned __int64 ft_scalar;
FILETIME ft_struct;
} FT;
/***
*__time64_t _time64(timeptr) - Get current system time and convert to a
* __time64_t value.
*
*Purpose:
* Gets the current date and time and stores it in internal 64-bit format
* (__time64_t). The time is returned and stored via the pointer passed in
* timeptr. If timeptr == NULL, the time is only returned, not stored in
* *timeptr. The internal (__time64_t) format is the number of seconds
* since 00:00:00, Jan 1 1970 (UTC).
*
*Entry:
* __time64_t *timeptr - pointer to long to store time in.
*
*Exit:
* returns the current time.
*
*Exceptions:
*
*******************************************************************************/
__time64_t __cdecl _time64 (
__time64_t *timeptr
)
{
__time64_t tim;
FT nt_time;
GetSystemTimeAsFileTime( &(nt_time.ft_struct) );
tim = (__time64_t)((nt_time.ft_scalar - EPOCH_BIAS) / 10000000i64);
if (timeptr)
*timeptr = tim; /* store time if requested */
return tim;
}