73ef4ff3
 Hu Chunming
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/* Copyright (C) 2008 by Daniel Stenberg et al
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted, provided
* that the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. M.I.T. makes no representations about the
* suitability of this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#include "ares_setup.h"
#include "ares.h"
#include "ares_private.h"
#if defined(WIN32) && !defined(MSDOS)
struct timeval ares__tvnow(void)
{
/*
** GetTickCount() is available on _all_ Windows versions from W95 up
** to nowadays. Returns milliseconds elapsed since last system boot,
** increases monotonically and wraps once 49.7 days have elapsed.
*/
struct timeval now;
DWORD milliseconds = GetTickCount();
now.tv_sec = milliseconds / 1000;
now.tv_usec = (milliseconds % 1000) * 1000;
return now;
}
#elif defined(HAVE_CLOCK_GETTIME_MONOTONIC)
struct timeval ares__tvnow(void)
{
/*
** clock_gettime() is granted to be increased monotonically when the
** monotonic clock is queried. Time starting point is unspecified, it
** could be the system start-up time, the Epoch, or something else,
** in any case the time starting point does not change once that the
** system has started up.
*/
struct timeval now;
struct timespec tsnow;
if(0 == clock_gettime(CLOCK_MONOTONIC, &tsnow)) {
now.tv_sec = tsnow.tv_sec;
now.tv_usec = tsnow.tv_nsec / 1000;
}
/*
** Even when the configure process has truly detected monotonic clock
** availability, it might happen that it is not actually available at
** run-time. When this occurs simply fallback to other time source.
*/
#ifdef HAVE_GETTIMEOFDAY
else
(void)gettimeofday(&now, NULL); /* LCOV_EXCL_LINE */
#else
else {
now.tv_sec = (long)time(NULL);
now.tv_usec = 0;
}
#endif
return now;
}
#elif defined(HAVE_GETTIMEOFDAY)
struct timeval ares__tvnow(void)
{
/*
** gettimeofday() is not granted to be increased monotonically, due to
** clock drifting and external source time synchronization it can jump
** forward or backward in time.
*/
struct timeval now;
(void)gettimeofday(&now, NULL);
return now;
}
#else
struct timeval ares__tvnow(void)
{
/*
** time() returns the value of time in seconds since the Epoch.
*/
struct timeval now;
now.tv_sec = (long)time(NULL);
now.tv_usec = 0;
return now;
}
#endif
#if 0 /* Not used */
/*
* Make sure that the first argument is the more recent time, as otherwise
* we'll get a weird negative time-diff back...
*
* Returns: the time difference in number of milliseconds.
*/
long ares__tvdiff(struct timeval newer, struct timeval older)
{
return (newer.tv_sec-older.tv_sec)*1000+
(newer.tv_usec-older.tv_usec)/1000;
}
#endif
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