In logging I want to add a log entry time in format: GGYG.MM.DD. // CC.MM.SS // mmm,
where MMM is milliseconds.
Can I make it with C++ without manual recalculation of seconds since 1900? This refers to learn all the date entirely. Milliseconds are understandable, considered separately.

Answer 1, Authority 100%

Solution for Windows with “honest” milliseconds:

# include & lt; windows.h & gt;
#Include & lt; stdio.h & gt;
INT MAIN ()
{
  SystemTime ST;
  Getlocaltime (& amp; ST);
  PrintF ("% D-% 02D-% 02D% 02D:% 02D:% 02D.% 03D",
       ST.WYEAR,
       ST.WMONTH,
       ST.WDay,
       St.Whour,
       st.Wminute
       St.Wsecond,
       st.wmilliseconds);
}

2016-04-13 18: 26: 45.266

execution result

Answer 2, Authority 67%

# include & lt; chrono & gt;
Using Namespace Std :: Chrono;
// Main ...
Milliseconds MS = DURATION_CAST & LT; Milliseconds & gt; (
  System_Clock :: Now (). Time_Since_epoch ()
);

Answer 3, Authority 67%

For * NIX (checked in Ubuntu) and Windows (checked in MingW), you can use POSIX.1-2001 GetTimeofday (though, already outdated to 8th year, with recommendation POSIX.1-2008 use Clock_getTime (which is missing in Mingw available to me)).

# include & lt; stdlib.h & gt;
#Include & lt; stdio.h & gt;
#Include & lt; Time.h & gt;
#Include & lt; sys / time.h & gt;
#Define Datefmt "yyyy.mm.dd // HH: MM: SS // mmm"
#ifdef win32.
Struct TM *
GMTime_R (TIME_T * T, STRUCT TM * R)
{
 STRUCT TM * Res = GMTime (T);
 if (res) {
  * R = * Res;
  res = r;
 }
 Return R;
}
Struct TM *
Localtime_R (Time_t * T, Struct TM * R)
{
 STRUCT TM * Res = Localtime (T);
 if (res) {
  * R = * Res;
  res = r;
 }
 Return R;
}
#Endif
int.
Main (Int AC, char ** AV)
{
 STRUCT TIMEVAL TV;
 STRUCT TIMEZONE TZ;
 Struct TM TM;
 GetTimeOFDay (& amp; TV, & amp; tz); // instead of tz you can 0 if you yourself are not going to play with TZ
 // GMTime_R (& amp; tv.tv_sec, & amp; tm); // UTC.
 Localtime_R (& amp; TV.tv_sec, & amp; TM);
 Char Now [Sizeof (DateFMT) + 1] = "Strftime () error";
 Size_t L = STRFTime (NOW, SIZEOF (NOW), "% y.% m.% d //% H.% M.% S //", & amp; TM);
 if (L)
  SPRINTF (NOW + L, "% 03D", (int) TV.tv_usec / 1000); // I think that in such tasks rounding is too
 RETURN PUTS (NOW) == EOF;
}

It turns out that there is no localtime_r () / gmtime_r () also strftime () in Windows does not understand % G and % T .

Answer 4, Authority 33%

It is suitable for a solution only for Windows?

/ * straftime example * /
#Include & lt; stdio.h & gt; / * Puts * /
#Include & lt; Time.h & gt; / * Time_T, Struct TM, Time, Localtime, Strftime * /
#Include & lt; Windows.h & gt;
INT MAIN ()
{
  Time_t Rawtime;
  Struct TM * TimeInfo;
  Char Buffer [80];
  Time (& amp; rawtime);
  TimeInfo = Localtime (& amp; rawtime);
  Strftime (Buffer, 80, "NOW IT'S% Y.% m.% d //% H.% M.% S //", timeinfo);
  PrintF ("% s", buffer);
  PrintF ("% d \ n", gettickcount ()% 1000);
  Return 0;
}