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std::get_time

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< cpp‎ | io‎ | manip
 
C++
 
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Time and money I/O
(C++11)
get_time
(C++11)
(C++11)
(C++11)
Quoted manipulator
(C++14)
 
Defined in header <iomanip>
template< class CharT >
/*unspecified*/ get_time( std::tm* tmb, const CharT* fmt);
 (since C++11)

When used in an expression in >> get_time(tmb, fmt), parses the character input as a date/time value according to format string fmt according to the std::time_get facet of the locale currently imbued in the output stream out. The resultant value is stored in a std::tm object pointed to by tmb.

Contents

[edit] Parameters

tmb - valid pointer to the std::tm object where the result will be stored
fmt - pointer to a null-terminated CharT string specifying the conversion format

The format string consists of zero or more conversion specifiers, whitespace characters, and ordinary characters (except %). Each ordinary character is expected to match one character in the input stream in case-insensitive comparison. Each whitespace character matches arbitrary whitespace in the input string. 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 format specifiers match the POSIX function strptime():

Conversion
specifier 		Explanation Writes to fields
% matches a literal %. The full conversion specification must be %%. (none)
t matches any whitespace. (none)
n matches any whitespace. (none)
Year
Y parses full year as a 4 digit decimal number, leading zeroes permitted but not required tm_year
EY parses year in the alternative representation, e.g.平成23年 (year Heisei 23) which writes 2011 to tm_year in ja_JP locale tm_year
y parses last 2 digits of year as a decimal number. Range [69,99] results in values 1969 to 1999, range [00,68] results in 2000-2068 tm_year
Oy parses last 2 digits of year using the alternative numeric system, e.g. 十一 is parsed as 11 in ja_JP locale tm_year
Ey parses year as offset from locale's alternative calendar period %EC tm_year
C parses the first 2 digits of year as a decimal number (range [00,99]) tm_year
EC parses the name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP tm_year
Month
b parses the month name, either full or abbreviated, e.g. Oct tm_mon
h synonym of b tm_mon
B synonym of b tm_mon
m parses the month as a decimal number (range [01,12]), leading zeroes permitted but not required tm_mon
Om parses the month using the alternative numeric system, e.g. 十二 parses as 12 in ja_JP locale tm_mon
Week
U parses the week of the year as a decimal number (Sunday is the first day of the week) (range [00,53]), leading zeroes permitted but not required tm_year, tm_wday, tm_yday
OU parses the week of the year, as by %U, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale tm_year, tm_wday, tm_yday
W parses the week of the year as a decimal number (Monday is the first day of the week) (range [00,53]), leading zeroes permitted but not required tm_year, tm_wday, tm_yday
OW parses the week of the year, as by %W, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale tm_year, tm_wday, tm_yday
Day of the year/month
j parses day of the year as a decimal number (range [001,366]), leading zeroes permitted but not required tm_yday
d parses the day of the month as a decimal number (range [01,31]), leading zeroes permitted but not required tm_mday
Od parses the day of the month using the alternative numeric system, e.g 二十七 parses as 27 in ja_JP locale, leading zeroes permitted but not required tm_mday
e synonym of d tm_mday
Oe synonym of Od tm_mday
Day of the week
a parses the name of the day of the week, either full or abbreviated, e.g. Fri tm_wday
A synonym of a tm_wday
w parses weekday as a decimal number, where Sunday is 0 (range [0-6]) tm_wday
Ow parses weekday as a decimal number, where Sunday is 0, using the alternative numeric system, e.g. 二 parses as 2 in ja_JP locale tm_wday
Hour, minute, second
H parses the hour as a decimal number, 24 hour clock (range [00-23]), leading zeroes permitted but not required tm_hour
OH parses hour from 24-hour clock using the alternative numeric system, e.g. 十八 parses as 18 in ja_JP locale tm_hour
I parses hour as a decimal number, 12 hour clock (range [01,12]), leading zeroes permitted but not required tm_hour
OI parses hour from 12-hour clock using the alternative numeric system, e.g. 六 reads as 06 in ja_JP locale tm_hour
M parses minute as a decimal number (range [00,59]), leading zeroes permitted but not required tm_min
OM parses minute using the alternative numeric system, e.g. 二十五 parses as 25 in ja_JP locale tm_min
S parses second as a decimal number (range [00,60]), leading zeroes permitted but not required tm_sec
OS parses second using the alternative numeric system, e.g. 二十四 parses as 24 in ja_JP locale tm_sec
Other
c parses the locale's standard date and time string format, e.g. Sun Oct 17 04:41:13 2010 (locale dependent) all
Ec parses the locale's alternative date and time string format, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale all
x parses the locale's standard date representation all
Ex parses the locale's alternative date representation, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale all
X parses the locale's standard time representation all
EX parses the locale's alternative time representation all
D equivalent to "%m / %d / %y " tm_mon, tm_mday, tm_year
r parses locale's standard 12-hour clock time (in POSIX, "%I : %M : %S %p") tm_hour, tm_min, tm_sec
R equivalent to "%H : %M" tm_hour, tm_min
T equivalent to "%H : %M : %S" tm_hour, tm_min, tm_sec
p parses the locale's equivalent of a.m. or p.m. tm_hour

Note: tm_isdst is not written to, and needs to be set explicitly for use with functions such as mktime


[edit] Return value

Returns an object of unspecified type such that if in is the name of an input stream of type std::basic_istream<CharT, Traits>, then the expression in >> get_time(tmb, fmt) behaves as if the following code was executed:

typedef std::istreambuf_iterator<CharT, Traits> Iter;
typedef std::time_get<CharT, Iter> TimeGet;
std::ios_base::iostate err = std::ios_base::goodbit;
const TimeGet& tg = std::use_facet<TimeGet>(in.getloc());
tg.get(Iter(in.rdbuf()), Iter(), in, err, tmb, fmt, fmt + traits::length(fmt));
if (err != std::ios_base::goodbit)
    in.setstate(err);

[edit] Notes

As specified in std::time_get::do_get, which this function calls, it's unspecified if this function zero out the fields in *tmb that are not set directly by the conversion specifiers that appear in fmt: portable programs should initialize every field of *tmb to zero before calling std::get_time.

[edit] Example

Run this code
#include <iostream>
#include <sstream>
#include <locale>
#include <iomanip>
 
int main()
{
    std::tm t = {};
    std::istringstream ss("2011-Februar-18 23:12:34");
    ss.imbue(std::locale("de_DE.utf-8"));
    ss >> std::get_time(&t, "%Y-%b-%d %H:%M:%S");
    if (ss.fail()) {
        std::cout << "Parse failed\n";
    } else {
        std::cout << std::put_time(&t, "%c") << '\n';
    }
}

Output: 

Sun Feb 18 23:12:34 2011

[edit] See also

 parses time/date values from an input character sequence into struct std::tm
(class template) [edit]
(C++11)
 formats and outputs a date/time value according to the specified format
(function template) [edit]
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