有人可以帮我在Windows XP上的Visual Studio C ++ 2008中使用gettimeofday()函数吗?这是我在网上某处找到的代码:
#include < time.h >
#include <windows.h>
#if defined(_MSC_VER) || defined(_MSC_EXTENSIONS)
#define DELTA_EPOCH_IN_MICROSECS 11644473600000000Ui64
#else
#define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL
#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;
unsigned __int64 tmpres = 0;
static int tzflag;
if (NULL != tv)
{
GetSystemTimeAsFileTime(&ft);
tmpres |= ft.dwHighDateTime;
tmpres <<= 32;
tmpres |= ft.dwLowDateTime;
/*converting file time to unix epoch*/
tmpres -= DELTA_EPOCH_IN_MICROSECS;
tmpres /= 10; /*convert into microseconds*/
tv->tv_sec = (long)(tmpres / 1000000UL);
tv->tv_usec = (long)(tmpres % 1000000UL);
}
if (NULL != tz)
{
if (!tzflag)
{
_tzset();
tzflag++;
}
tz->tz_minuteswest = _timezone / 60;
tz->tz_dsttime = _daylight;
}
return 0;
}
...
// call gettimeofday()
gettimeofday(&tv, &tz);
tm = localtime(&tv.tv_sec);
去年,当我使用VC ++ 6测试此代码时,它运行良好。但是现在当我使用VC ++ 2008时,出现了异常处理错误。那么关于如何使用gettimeofday或等效方法有什么想法吗?
感谢您的答复,我们将不胜感激:
在UNIX中,使用时区结构已过时。我不知道你为什么使用它。参见http://linux.about.com/od/commands/l/blcmdl2_gettime.htm,但是如果您想使用此结构来了解当地时间的GMT(UTC)时差,则将是下一个:tz_minuteswest是与GMT(UTC)时的分钟时差,而tz_dsttime是一个标志,指示日光正在使用中。
您的示例进行了一些更改,在Visual C ++ 2008 Express中运行良好:
#include "stdafx.h"
#include <time.h>
#include <windows.h>
const __int64 DELTA_EPOCH_IN_MICROSECS= 11644473600000000;
/* IN UNIX the use of the timezone struct is obsolete;
I don't know why you use it. See http://linux.about.com/od/commands/l/blcmdl2_gettime.htm
But if you want to use this structure to know about GMT(UTC) diffrence from your local time
it will be next: tz_minuteswest is the real diffrence in minutes from GMT(UTC) and a tz_dsttime is a flag
indicates whether daylight is now in use
*/
struct timezone2
{
__int32 tz_minuteswest; /* minutes W of Greenwich */
bool tz_dsttime; /* type of dst correction */
};
struct timeval2 {
__int32 tv_sec; /* seconds */
__int32 tv_usec; /* microseconds */
};
int gettimeofday(struct timeval2 *tv/*in*/, struct timezone2 *tz/*in*/)
{
FILETIME ft;
__int64 tmpres = 0;
TIME_ZONE_INFORMATION tz_winapi;
int rez=0;
ZeroMemory(&ft,sizeof(ft));
ZeroMemory(&tz_winapi,sizeof(tz_winapi));
GetSystemTimeAsFileTime(&ft);
tmpres = ft.dwHighDateTime;
tmpres <<= 32;
tmpres |= ft.dwLowDateTime;
/*converting file time to unix epoch*/
tmpres /= 10; /*convert into microseconds*/
tmpres -= DELTA_EPOCH_IN_MICROSECS;
tv->tv_sec = (__int32)(tmpres*0.000001);
tv->tv_usec =(tmpres%1000000);
//_tzset(),don't work properly, so we use GetTimeZoneInformation
rez=GetTimeZoneInformation(&tz_winapi);
tz->tz_dsttime=(rez==2)?true:false;
tz->tz_minuteswest = tz_winapi.Bias + ((rez==2)?tz_winapi.DaylightBias:0);
return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
struct timeval2 tv;
struct timezone2 tz;
struct tm *tm1;
time_t time1;
ZeroMemory(&tv,sizeof(tv));
ZeroMemory(&tz,sizeof(tz));
gettimeofday(&tv, &tz); // call gettimeofday()
time1=tv.tv_sec;
tm1 = localtime(&time1);
FILE *f;
f=fopen("rez.txt","w");
fprintf(f,"%04d.%02d.%02d %02d:%02d:%02d\n",1900+tm1->tm_year,1+tm1->tm_mon,tm1->tm_mday,tm1->tm_hour,tm1->tm_min,tm1->tm_sec);
fprintf(f,"Diffrence between GMT(UTC) and local time=%d %s\n",tz.tz_minuteswest,"minutes");
fprintf(f,"Is Daylight now=%s\n",tz.tz_dsttime?"Yes":"No");
fclose(f);
return 0;
}
以秒为单位的简单秒表
FWIW:这与Kate相似,但我只想提一下,if某人正在寻找C ++中最简单的秒表(以秒为单位)。我知道这没什么大不了的。它只有1秒的分辨率,因此,如果您想微秒,请继续其他示例。
double seconds=0;
time_t timer1, timer2;
time(&timer1); /* get current time */
...
time(&timer2); /* get current time later */
seconds = difftime(timer2,timer1);
有几种不同的类型可以代表一个时间。这是我最近使用的一些代码:
time_t now;
tm* local;
time(&now);
local=localtime(&now);
然后我继续从local
的片段构建一个字符串,但是您现在可以做您想做的事情。
凯特
就我而言,它的工作方式如下:由于我想找到平均运行时间,因此我使用了:首先在程序开头添加,然后:初始化样本= 100(例如);
time_t t_start,t_end;
time(&t_start); //get the current time
//program that needs to be timed
time(&t_end); //get the time at the end of execution of the program
seconds = (difftime(t_start,t_end))/samples;//calculate the difference