Datetime interoperation between c plus plus and .net

Here is the senario in my requirements:

  I need store datetime value in a serialization file(binary file). the file will be transfer to server side by network. the server-side is used c plus plus and it is responsible for parse the file tranfer from network. the file content contains different type data. of course,datetime value just be contained. Unfortunally, I write data to file use .net.

    How to store datetime value without use string format like this yyyy-MM-dd HH:mm:ss?

I got an idea, windows use 64-bit value to present datetime format value. I also can convert datetime to 64-bit value.

Let me to this:

private static DateTime origin = System.TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1, 0, 0, 0));

 public static System.DateTime Convert(UInt64 t)
 {
      DateTime convertedValue = origin + new TimeSpan((long)t * TimeSpan.TicksPerDay);
      if (System.TimeZone.CurrentTimeZone.IsDaylightSavingTime(convertedValue) == true)
      {
          System.Globalization.DaylightTime daylightTime = System.TimeZone.CurrentTimeZone.GetDaylightChanges(convertedValue.Year);
          convertedValue = convertedValue + daylightTime.Delta;
      }
      return convertedValue;
  }
 public static UInt64 ConvertBack(System.DateTime value)
 {
      DateTime convertedValue = value;
      if (System.TimeZone.CurrentTimeZone.IsDaylightSavingTime(convertedValue) == true)
      {
          System.Globalization.DaylightTime daylightTime = System.TimeZone.CurrentTimeZone.GetDaylightChanges(convertedValue.Year);
          convertedValue = convertedValue - daylightTime.Delta;
     }
     long diff = convertedValue.Ticks - origin.Ticks;
     return (UInt64)(diff / TimeSpan.TicksPerDay);
  }

 

I store total seconds in file. and I will parse the datetime easily in the server side .

the following is the c plus plus code:

struct tm gettime (long value)
{
    time_t time = time_t(vlaue);
    struct tm t;
    localtime_s (&t, &time);
    //struct tm *tm2 = localtime(&ltime);
    t.tm_year += 1900;
    t.tm_mon += 1;

    return t;
}

 

Great,you only need use localtime() function to do this. Is it so easy?

time_t is defined as a 64-bit int number type. in crtdefs.h header file, you will find this:

typedef __int64 __time64_t;     /* 64-bit time value */
typedef __time64_t time_t;      /* time value */

 

tm as struct defined in wchar.c

struct tm {
        int tm_sec;     /* seconds after the minute - [0,59] */
        int tm_min;     /* minutes after the hour - [0,59] */
        int tm_hour;    /* hours since midnight - [0,23] */
        int tm_mday;    /* day of the month - [1,31] */
        int tm_mon;     /* months since January - [0,11] */
        int tm_year;    /* years since 1900 */
        int tm_wday;    /* days since Sunday - [0,6] */
        int tm_yday;    /* days since January 1 - [0,365] */
        int tm_isdst;   /* daylight savings time flag */
        };

 

ok, util now. I solve the interoperation problem. It seems very easy.um…