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# std::time_put::put, std::time_put::do_put

From cppreference.com
< cpp‎ | locale‎ | time put

Defined in header `<locale>` |  |
public: iter_type put( iter_type out, std::ios_base& str, char_type fill, const std::tm* t, const CharT* fmtbeg, const CharT* fmtend ) const; | (1) |
public: iter_type put( iter_type out, std::ios_base& str, char_type fill, const std::tm* t, char format, char modifier = 0 ) const; | (2) |
protected: virtual iter_type do_put( iter_type out, std::ios_base& str, char_type fill, const std::tm* t, char format, char modifier ) const; | (3) |

Converts the calendar date and time stored in the std::tm object pointed to by `t` into a character string, according to the format string `[fmtbeg, fmtend)`. The format string is the same as used by std::srtftime, but each format specifier is processed by an individual call to `do_put()`, which can be customized by extending this facet.

1) Steps through the character sequence `[fmtbeg, fmtend)`, examining the characters. Every character that is not a part of a format sequence is written to the output iterator `out` immediately. To identify format sequences, this function narrows the next character `c` in `[fmtbeg, fmtend)` as if by std::ctype<char_type>(str.getloc()).narrow(c,0) and if it equals '%', the next one or two characters are compared to the list of format sequences recognized by std::strftime plus any additional implementation-defined formats supported by this locale. For each valid format sequence, a call to do_put(out, str, fill, t, format, modifier) is made, where `format` is the format sequence character, and `modifier` is the optional format sequence modifier ('E' or 'O'). A value of '\0' is used if the modifier is absent.
2) Calls the `do_put` member function of the most derived class.
3) Converts the calendar date and time stored in the std::tm object pointed to by `t` into a character string, according to the format conversion sequence formed by concatenating '%', the value of `modifier` if not '\0', and the value of `format`. The format is interpreted the same way as the function std::strftime, except that the formats that are described as locale-dependent are defined by this locale, and additional format specifiers may be supported (the `fill` argument is provided for these implementation-defined format specifiers to use). The string is written to the output iterator `out`.

### [edit] Parameters

out | - | output iterator where the result of the conversion is written
str | - | a stream object that this function uses to obtain locale facets when needed, e.g. std::ctype to narrow characters
t | - | pointer to the std::tm object from which the date/time values are obtained
fmtbeg | - | pointer to the first character of a sequence of char_type characters specifying the conversion format 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 specifier | Explanation | Used fields
--- | --- | ---
`%` | writes literal `%`. The full conversion specification must be `%%`. |
`n` (C++11) | writes newline character |
`t` (C++11) | writes horizontal tab character |
Year
`Y` | writes year as a decimal number, e.g. 2017 | `tm_year`
`EY` (C++11) | writes year in the alternative representation, e.g.平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | `tm_year`
`y` | writes last 2 digits of year as a decimal number (range `[00,99]`) | `tm_year`
`Oy` (C++11) | writes last 2 digits of year using the alternative numeric system, e.g. 十一 instead of 11 in ja_JP locale | `tm_year`
`Ey` (C++11) | writes year as offset from locale's alternative calendar period `%EC` (locale-dependent) | `tm_year`
`C` (C++11) | writes first 2 digits of year as a decimal number (range `[00,99]`) | `tm_year`
`EC` (C++11) | writes name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP | `tm_year`
`G` (C++11) | writes ISO 8601 week-based year, i.e. the year that contains the specified week. In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements: Includes January 4 Includes first Thursday of the year | `tm_year`, `tm_wday`, `tm_yday`
`g` (C++11) | writes last 2 digits of ISO 8601 week-based year, i.e. the year that contains the specified week (range `[00,99]`). In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements: Includes January 4 Includes first Thursday of the year | `tm_year`, `tm_wday`, `tm_yday`
Month
`b` | writes abbreviated month name, e.g. `Oct` (locale dependent) | `tm_mon`
`h` (C++11) | synonym of `b` | `tm_mon`
`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` (C++11) | writes month using the alternative numeric system, e.g. 十二 instead of 12 in ja_JP locale | `tm_mon`
Week
`U` | writes week of the year as a decimal number (Sunday is the first day of the week) (range `[00,53]`) | `tm_year`, `tm_wday`, `tm_yday`
`OU` (C++11) | writes week of the year, as by `%U`, using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | `tm_year`, `tm_wday`, `tm_yday`
`W` | writes week of the year as a decimal number (Monday is the first day of the week) (range `[00,53]`) | `tm_year`, `tm_wday`, `tm_yday`
`OW` (C++11) | writes week of the year, as by `%W`, using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | `tm_year`, `tm_wday`, `tm_yday`
`V` (C++11) | writes ISO 8601 week of the year (range `[01,53]`). In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements: Includes January 4 Includes first Thursday of the year | `tm_year`, `tm_wday`, `tm_yday`
`OV` (C++11) | writes week of the year, as by `%V`, using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | `tm_year`, `tm_wday`, `tm_yday`
Day of the year/month
`j` | writes day of the year as a decimal number (range `[001,366]`) | `tm_yday`
`d` | writes day of the month as a decimal number (range `[01,31]`) | `tm_mday`
`Od` (C++11) | writes zero-based day of the month using the alternative numeric system, e.g 二十七 instead of 23 in ja_JP locale Single character is preceded by a space. | `tm_mday`
`e` (C++11) | writes day of the month as a decimal number (range `[1,31]`). Single digit is preceded by a space. | `tm_mday`
`Oe` (C++11) | writes one-based day of the month using the alternative numeric system, e.g. 二十七 instead of 27 in ja_JP locale Single character is preceded by a space. | `tm_mday`
Day of the week
`a` | writes abbreviated weekday name, e.g. `Fri` (locale dependent) | `tm_wday`
`A` | writes full weekday name, e.g. `Friday` (locale dependent) | `tm_wday`
`w` | writes weekday as a decimal number, where Sunday is `0` (range `[0-6]`) | `tm_wday`
`Ow` (C++11) | writes weekday, where Sunday is `0`, using the alternative numeric system, e.g. 二 instead of 2 in ja_JP locale | `tm_wday`
`u` (C++11) | writes weekday as a decimal number, where Monday is `1` (ISO 8601 format) (range `[1-7]`) | `tm_wday`
`Ou` (C++11) | writes weekday, where Monday is `1`, using the alternative numeric system, e.g. 二 instead of 2 in ja_JP locale | `tm_wday`
Hour, minute, second
`H` | writes hour as a decimal number, 24 hour clock (range `[00-23]`) | `tm_hour`
`OH` (C++11) | writes hour from 24-hour clock using the alternative numeric system, e.g. 十八 instead of 18 in ja_JP locale | `tm_hour`
`I` | writes hour as a decimal number, 12 hour clock (range `[01,12]`) | `tm_hour`
`OI` (C++11) | writes hour from 12-hour clock using the alternative numeric system, e.g. 六 instead of 06 in ja_JP locale | `tm_hour`
`M` | writes minute as a decimal number (range `[00,59]`) | `tm_min`
`OM` (C++11) | writes minute using the alternative numeric system, e.g. 二十五 instead of 25 in ja_JP locale | `tm_min`
`S` | writes second as a decimal number (range `[00,60]`) | `tm_sec`
`OS` (C++11) | writes second using the alternative numeric system, e.g. 二十四 instead of 24 in ja_JP locale | `tm_sec`
Other
`c` | writes standard date and time string, e.g. `Sun Oct 17 04:41:13 2010` (locale dependent) | all
`Ec` (C++11) | writes alternative date and time string, e.g. using 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all
`x` | writes localized date representation (locale dependent) | all
`Ex` (C++11) | writes alternative date representation, e.g. using 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all
`X` | writes localized time representation (locale dependent) | all
`EX` (C++11) | writes alternative time representation (locale dependent) | all
`D` (C++11) | equivalent to "%m/%d/%y" | `tm_mon`, `tm_mday`, `tm_year`
`F` (C++11) | equivalent to "%Y-%m-%d" (the ISO 8601 date format) | `tm_mon`, `tm_mday`, `tm_year`
`r` (C++11) | writes localized 12-hour clock time (locale dependent) | `tm_hour`, `tm_min`, `tm_sec`
`R` (C++11) | equivalent to "%H:%M" | `tm_hour`, `tm_min`
`T` (C++11) | equivalent to "%H:%M:%S" (the ISO 8601 time format) | `tm_hour`, `tm_min`, `tm_sec`
`p` | writes localized a.m. or p.m. (locale dependent) | `tm_hour`
`z` (C++11) | writes offset from UTC in the ISO 8601 format (e.g. `-0430`), or no characters if the time zone information is not available | `tm_isdst`
`Z` | writes time zone name or abbreviation, or no characters if the time zone information is not available (locale dependent) | `tm_isdst`
fmtend | - | pointer one past the last character of a sequence of char_type characters specifying the conversion format
fill | - | fill character (usually space)
format | - | the character that names a conversion specifier
modifier | - | the optional modifier that may appear between `%` and the conversion specifier

### [edit] Return value

Iterator pointing one past the last character that was produced .

### [edit] Notes

No error handling is provided.

The `fill` character is provided for those implementation-defined format specifiers and for the user-defined overrides of `do_put()` that use padding and filling logic. Such implementations typically make use of the formatting flags from `str`.

### [edit] Example

Run this code

    #include <iostream>
    #include <sstream>
    #include <iomanip>
    #include <ctime>

    void try_time_put(const std::tm* t, const std::string& fmt)
    {
            std::cout.imbue(std::locale());
            std::cout << "In the locale '" << std::cout.getloc().name() << "' : '";

            std::use_facet<std::time_put<char>>(std::cout.getloc()).put(
                        std::ostreambuf_iterator<char>(std::cout),
                        std::cout, ' ', t, &fmt[0], &fmt[0] + fmt.size());

            std::cout << "'\n";
    }

    int main()
    {
        std::time_t t = std::time(NULL);
        std::tm tm = *std::localtime(&t);

        std::string fmt = "%c";
        std::cout << "Using the format string '" << fmt
                  << "' to format the time: " << std::ctime(&t) << '\n';

        std::locale::global(std::locale("de_DE.utf8"));
        try_time_put(&tm, fmt);

        std::locale::global(std::locale("el_GR.utf8"));
        try_time_put(&tm, fmt);

        std::locale::global(std::locale("ja_JP.utf8"));
        try_time_put(&tm, fmt);
    }

Output:

    Using the format string '%c' to format the time: Mon Feb 11 22:58:50 2013

    In the locale 'de_DE.utf8' : 'Mo 11 Feb 2013 23:02:38 EST'
    In the locale 'el_GR.utf8' : 'Δευ 11 Φεβ 2013 11:02:38 μμ EST'
    In the locale 'ja_JP.utf8' : '2013年02月11日 23時02分38秒'

### [edit] See also

put_time (C++11) | formats and outputs a date/time value according to the specified format (function template) [edit]
do_get [virtual] (C++11) | extracts date/time components from input stream, according to the specified format (virtual protected member function of `std::time_get`) [edit]

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