std::put_time(3)

NAME
std::put_time - std::put_time

Synopsis
   Defined in header <iomanip>
   template< class CharT > (since C++11)
   /*unspecified*/ put_time( const std::tm* tmb, const CharT* fmt );
   When used in an expression out << put_time(tmb, fmt), converts the date and time
   information from a given calendar time tmb to a character string according to format
   string fmt, as if by calling std::strftime, std::wcsftime, or analog (depending on
   CharT), according to the std::time_put facet of the locale currently imbued in the
   output stream out.

Parameters
   tmb - pointer to the calendar time structure as obtained from std::localtime or
         std::gmtime
   fmt - pointer to a null-terminated CharT string specifying the format of conversion
   Format string
   The format string consists of zero or more conversion specifiers and ordinary
   characters (except %). All ordinary characters, including the terminating null
   character, are copied to the output string without modification. Each conversion
   specification begins with % character, optionally followed by E or O modifier
   (ignored if unsupported by the locale), followed by the character that determines
   the behavior of the specifier. The following format specifiers are available:
   Conversion Explanation Used fields
   specifier
       % writes literal %. The full conversion specification
              must be %%.
       n writes newline character
    (C++11)
       t writes horizontal tab character
    (C++11)
                        Year
       Y writes year as a decimal number, e.g. 2017 tm_year
       EY writes year in the alternative representation, e.g.平
    (C++11) 成23年 (year Heisei 23) instead of 2011年 (year 2011) tm_year
              in ja_JP locale
       y writes last 2 digits of year as a decimal number (range tm_year
              [00,99])
       Oy writes last 2 digits of year using the alternative tm_year
    (C++11) numeric system, e.g. 十一 instead of 11 in ja_JP locale
       Ey writes year as offset from locale's alternative tm_year
    (C++11) calendar period %EC (locale-dependent)
       C writes first 2 digits of year as a decimal number tm_year
    (C++11) (range [00,99])
       EC writes name of the base year (period) in the locale's
    (C++11) alternative representation, e.g. 平成 (Heisei era) in tm_year
              ja_JP
              writes ISO 8601 week-based year, i.e. the year that
              contains the specified week.
       G In ISO 8601 weeks begin with Monday and the first week tm_year, tm_wday,
    (C++11) of the year must satisfy the following requirements: tm_yday
                * Includes January 4
                * Includes first Thursday of the year
              writes last 2 digits of ISO 8601 week-based year, i.e.
              the year that contains the specified week (range
              [00,99]).
       g tm_year, tm_wday,
    (C++11) In ISO 8601 weeks begin with Monday and the first week tm_yday
              of the year must satisfy the following requirements:
                * Includes January 4
                * Includes first Thursday of the year
                        Month
       b writes abbreviated month name, e.g. Oct (locale tm_mon
              dependent)
       h synonym of b tm_mon
    (C++11)
       B writes full month name, e.g. October (locale dependent) tm_mon
       m writes month as a decimal number (range [01,12]) tm_mon
       Om writes month using the alternative numeric system, e.g. tm_mon
    (C++11) 十二 instead of 12 in ja_JP locale
                        Week
       U writes week of the year as a decimal number (Sunday is tm_year, tm_wday,
              the first day of the week) (range [00,53]) tm_yday
       OU writes week of the year, as by %U, using the tm_year, tm_wday,
    (C++11) alternative numeric system, e.g. 五十二 instead of 52 tm_yday
              in ja_JP locale
       W writes week of the year as a decimal number (Monday is tm_year, tm_wday,
              the first day of the week) (range [00,53]) tm_yday
       OW writes week of the year, as by %W, using the tm_year, tm_wday,
    (C++11) alternative numeric system, e.g. 五十二 instead of 52 tm_yday
              in ja_JP locale
              writes ISO 8601 week of the year (range [01,53]).
       V In ISO 8601 weeks begin with Monday and the first week tm_year, tm_wday,
    (C++11) of the year must satisfy the following requirements: tm_yday
                * Includes January 4
                * Includes first Thursday of the year
       OV writes week of the year, as by %V, using the tm_year, tm_wday,
    (C++11) alternative numeric system, e.g. 五十二 instead of 52 tm_yday
              in ja_JP locale
                        Day of the year/month
       j writes day of the year as a decimal number (range tm_yday
              [001,366])
       d writes day of the month as a decimal number (range tm_mday
              [01,31])
              writes zero-based day of the month using the
       Od alternative numeric system, e.g. 二十七 instead of 27
    (C++11) in ja_JP locale tm_mday
              Single character is preceded by a space.
              writes day of the month as a decimal number (range
       e [1,31]). tm_mday
    (C++11)
              Single digit is preceded by a space.
              writes one-based day of the month using the alternative
       Oe numeric system, e.g. 二十七 instead of 27 in ja_JP
    (C++11) locale tm_mday
              Single character is preceded by a space.
                        Day of the week
       a writes abbreviated weekday name, e.g. Fri (locale tm_wday
              dependent)
       A writes full weekday name, e.g. Friday (locale tm_wday
              dependent)
       w writes weekday as a decimal number, where Sunday is 0 tm_wday
              (range [0-6])
       Ow writes weekday, where Sunday is 0, using the
    (C++11) alternative numeric system, e.g. 二 instead of 2 in tm_wday
              ja_JP locale
       u writes weekday as a decimal number, where Monday is 1 tm_wday
    (C++11) (ISO 8601 format) (range [1-7])
       Ou writes weekday, where Monday is 1, using the
    (C++11) alternative numeric system, e.g. 二 instead of 2 in tm_wday
              ja_JP locale
                        Hour, minute, second
       H writes hour as a decimal number, 24 hour clock (range tm_hour
              [00-23])
       OH writes hour from 24-hour clock using the alternative tm_hour
    (C++11) numeric system, e.g. 十八 instead of 18 in ja_JP locale
       I writes hour as a decimal number, 12 hour clock (range tm_hour
              [01,12])
       OI writes hour from 12-hour clock using the alternative tm_hour
    (C++11) numeric system, e.g. 六 instead of 06 in ja_JP locale
       M writes minute as a decimal number (range [00,59]) tm_min
       OM writes minute using the alternative numeric system, tm_min
    (C++11) e.g. 二十五 instead of 25 in ja_JP locale
       S writes second as a decimal number (range [00,60]) tm_sec
       OS writes second using the alternative numeric system, tm_sec
    (C++11) e.g. 二十四 instead of 24 in ja_JP locale

Other
       c writes standard date and time string, e.g. Sun Oct 17 all
              04:41:13 2010 (locale dependent)
       Ec writes alternative date and time string, e.g. using 平
    (C++11) 成23年 (year Heisei 23) instead of 2011年 (year 2011) all
              in ja_JP locale
       x writes localized date representation (locale dependent) all
       Ex writes alternative date representation, e.g. using 平
    (C++11) 成23年 (year Heisei 23) instead of 2011年 (year 2011) all
              in ja_JP locale
       X writes localized time representation, e.g. 18:40:20 or all
              6:40:20 PM (locale dependent)
       EX writes alternative time representation (locale all
    (C++11) dependent)
       D equivalent to "%m/%d/%y" tm_mon, tm_mday,
    (C++11) tm_year
       F equivalent to "%Y-%m-%d" (the ISO 8601 date format) tm_mon, tm_mday,
    (C++11) tm_year
       r writes localized 12-hour clock time (locale dependent) tm_hour, tm_min,
    (C++11) tm_sec
       R equivalent to "%H:%M" tm_hour, tm_min
    (C++11)
       T equivalent to "%H:%M:%S" (the ISO 8601 time format) tm_hour, tm_min,
    (C++11) tm_sec
       p writes localized a.m. or p.m. (locale dependent) tm_hour
       z writes offset from UTC in the ISO 8601 format (e.g.
    (C++11) -0430), or no characters if the time zone information tm_isdst
              is not available
              writes locale-dependent time zone name or abbreviation,
       Z or no characters if the time zone information is not tm_isdst
              available

Return value
   An object of unspecified type such that
     * if out is an object of type std::basic_ostream<CharT, Traits>, the expression
       out << put_time(tmb, fmt)
          * has type std::basic_ostream<CharT, Traits>&
          * has value out
          * behaves as if it called f(out, tmb, fmt)
   where the function f is defined as:
 template<class CharT, class Traits>
 void f(std::basic_ios<CharT, Traits>& str, const std::tm* tmb, const CharT* fmt)
 {
     using Iter = std::ostreambuf_iterator<CharT, Traits>;
     using TimePut = std::time_put<CharT, Iter>;
     const TimePut& tp = std::use_facet<TimePut>(str.getloc());
     const Iter end = tp.put(Iter(str.rdbuf()), str, str.fill(), tmb,
         fmt, fmt + Traits::length(fmt));
     if (end.failed())
         str.setstate(std::ios_base::badbit);
 }

Example
// Run this code
 #include <ctime>
 #include <iomanip>
 #include <iostream>
 int main()
 {
     std::time_t t = std::time(nullptr);
     std::tm tm = *std::localtime(&t);
     std::cout.imbue(std::locale("ru_RU.utf8"));
     std::cout << "ru_RU: " << std::put_time(&tm, "%c %Z") << '\n';
     std::cout.imbue(std::locale("ja_JP.utf8"));
     std::cout << "ja_JP: " << std::put_time(&tm, "%c %Z") << '\n';
 }

Possible output:
 ru_RU: Ср. 28 дек. 2011 10:21:16 EST
 ja_JP: 2011年12月28日 10時21分16秒 EST

See also
   time_put formats contents of std::tm for output as character sequence
            (class template)
   get_time parses a date/time value of specified format
   (C++11) (function template)
   strftime converts a std::tm object to custom textual representation
            (function)
   wcsftime converts a std::tm object to custom wide string textual representation
            (function)