source: lib/gettimeofday.c @ 89e2ff7

/*
 *
 * Copyright (c) 2007-2016 The University of Waikato, Hamilton, New Zealand.
 * All rights reserved.
 *
 * This file is part of libtrace.
 *
 * This code has been developed by the University of Waikato WAND
 * research group. For further information please see http://www.wand.net.nz/
 *
 * libtrace is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * libtrace is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 */
#include <time.h>

#ifndef _FILETIME_
#define _FILETIME_
typedef struct _FILETIME
{
    DWORD dwLowDateTime;
    DWORD dwHighDateTime;
} FILETIME;
#endif

#ifdef _MSC_VER
#define EPOCHFILETIME (116444736000000000i64)
#else
#define EPOCHFILETIME (116444736000000000LL)
#endif

struct timezone {
        int tz_minuteswest; /* minutes W of Greenwich */
        int tz_dsttime;         /* type of dst correction */
};


int gettimeofday(struct timeval *tv, struct timezone *tz)
{
    FILETIME        ft;
    LARGE_INTEGER   li;
    __int64         t;
    static int      tzflag;

    if (tv)
    {
        GetSystemTimeAsFileTime(&ft);
        li.LowPart  = ft.dwLowDateTime;
        li.HighPart = ft.dwHighDateTime;
        t  = li.QuadPart;       /* In 100-nanosecond intervals */
        t -= EPOCHFILETIME;     /* Offset to the Epoch time */
        t /= 10;                /* In microseconds */
        tv->tv_sec  = (long)(t / 1000000);
        tv->tv_usec = (long)(t % 1000000);
    }

    if (tz)
    {
        if (!tzflag)
        {
            _tzset();
            tzflag++;
        }
        tz->tz_minuteswest = _timezone / 60;
        tz->tz_dsttime = _daylight;
    }

    return 0;
}