Defined in header
public:iter_typeget(iter_typebeg,iter_typeend,std::ios_base&str,std::ios_base::iostate&err,std::tm*t,charformat,charmodifier=0)const; (1) (since C++11)public:iter_typeget(iter_typebeg,iter_typeend,std::ios_base&str,std::ios_base::iostate&err,std::tm*t,constchar_type*fmtbeg,constchar_type*fmtend)const; (2) (since C++11)protected:virtualiter_typedo_get(iter_typebeg,iter_typeend,std::ios_base&str,std::ios_base::iostate&err,std::tm*t,charformat,charmodifier)const; (3) (since C++11)1) Public member function, calls the protected virtual member function do_get of the most derived class.
2) Parses the date and time from the input character sequence [beg,end) according to the format provided in the character sequence [fmtbeg,fmtend). The format is expected to follow the format described below, although actual processing of each format specifier can be customized by overriding do_get. The get function performs the following: First, clears the error bits in err by executing err=std::ios_base::goodbit. Then enters a loop, which terminates whenever any of the following conditions becomes true (checked in this order):
a) All characters have been read from the format string (fmtbeg==fmtend).
b) There was a parsing error (err!=std::ios_base::goodbit).
c) All characters have been read from the input sequence (beg==end. If this condition terminates the loop, the function sets both eofbit and failbit in err.
In the body of the loop, the following steps take place:a) If the next character in the format string is '%', followed by one or two characters that form a valid
conversion specifier (see below), these characters are used in the call do_get(beg,end,str,err,t,format,modifier), where format is the primary conversion specifier character, and modifier is the optional modifier (which appears between % and the format character, if present). If there is no modifier, the value '\0' is used. If the format string is ambiguous or ends too early to determine the conversion specifier after '%', eofbit is set in err and the loop is terminated. If, after the call to do_get, no error bits are set in err, the function increments fmtbeg to point right after the conversion specifier and continues the loop.
b) If the next character is whitespace, as indicated by the locale provided in the stream str (i.e. std::isspace(*fmtbeg,str.getloc())==true, the function keeps incrementing fmtbeg until it either becomes equal to fmtend or points to a non-whitespace character.
c) If the next character in the format string is equivalent to the next character in the input stream according to case-insensitive comparison, the function advances both sequences by one character ++fmtbeg,++beg; and continues the loop, Otherwise, it sets the failbit in err.
3) Parses one conversion specifier from the input sequence [beg,end) and updates the
structure pointed to by t accordingly.
First, clears the error bits in err by executing err=std::ios_base::goodbit. Then reads characters from the input sequence [beg,end) that are expected by the
format specifier formed by combining '%', modifier (if not '\0'), and format. If the characters do not combine to form a valid conversion specifier, sets failbit in err. If the end of the input stream is reached after reading a character, sets eofbit in err. If the input string was parsed successfully, updates the corresponding fields of *t.For complex conversion specifiers, such as '%x' or '%c', or the directives that use the modifiers 'E' and 'O', the function may fail to determine some of the values to store in *t. In such case, it sets eofbit in err and leaves these fields in unspecified state.Parameters
beg - iterator designating the start of the sequence to parse end - one past the end iterator for the sequence to parse str - a stream object that this function uses to obtain locale facets when needed, e.g.
to skip whitespace or
to compare strings err - stream error flags object that is modified by this function to indicate errors t - pointer to the
object that will hold the result of this function call fmtbeg - pointer to the first character of a sequence of char_type characters specifying the conversion format (see below) fmtend - pointer one past the last character of a sequence of char_type characters specifying the conversion format format - the character that names a conversion specifier modifier - the optional modifier that may appear between % and the conversion specifier
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
:
Conversion
specifier Explanation Writes to fields %matches a literal %. The full conversion specification must be %%(none) tmatches any whitespace (none) nmatches any whitespace (none) Year Yparses full year as a 4 digit decimal number, leading zeroes permitted but not required tm_yearEYparses 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_yearyparses 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_yearOyparses last 2 digits of year using the alternative numeric system, e.g. 十一 is parsed as 11 in ja_JP locale tm_yearEyparses year as offset from locale's alternative calendar period %ECtm_yearCparses the first 2 digits of year as a decimal number (range [00,99]) tm_yearECparses the name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP tm_yearMonth bparses the month name, either full or abbreviated, e.g. Octtm_monhsynonym of btm_monBsynonym of btm_monmparses the month as a decimal number (range [01,12]), leading zeroes permitted but not required tm_monOmparses the month using the alternative numeric system, e.g. 十二 parses as 12 in ja_JP locale tm_monWeek Uparses 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_ydayOUparses 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_ydayWparses 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_ydayOWparses 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_ydayDay of the year/month jparses day of the year as a decimal number (range [001,366]), leading zeroes permitted but not required tm_ydaydparses the day of the month as a decimal number (range [01,31]), leading zeroes permitted but not required tm_mdayOdparses 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_mdayesynonym of dtm_mdayOesynonym of Odtm_mdayDay of the week aparses the name of the day of the week, either full or abbreviated, e.g. Fritm_wdayAsynonym of atm_wdaywparses weekday as a decimal number, where Sunday is 0 (range [0-6]) tm_wdayOwparses 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_wdayHour, minute, second Hparses the hour as a decimal number, 24 hour clock (range [00-23]), leading zeroes permitted but not required tm_hourOHparses hour from 24-hour clock using the alternative numeric system, e.g. 十八 parses as 18 in ja_JP locale tm_hourIparses hour as a decimal number, 12 hour clock (range [01,12]), leading zeroes permitted but not required tm_hourOIparses hour from 12-hour clock using the alternative numeric system, e.g. 六 reads as 06 in ja_JP locale tm_hourMparses minute as a decimal number (range [00,59]), leading zeroes permitted but not required tm_minOMparses minute using the alternative numeric system, e.g. 二十五 parses as 25 in ja_JP locale tm_minSparses second as a decimal number (range [00,60]), leading zeroes permitted but not required tm_secOSparses second using the alternative numeric system, e.g. 二十四 parses as 24 in ja_JP locale tm_secOther cparses the locale's standard date and time string format, e.g. Sun Oct 17 04:41:13 2010 (locale dependent) all Ecparses 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 xparses the locale's standard date representation all Exparses 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 Xparses the locale's standard time representation all EXparses the locale's alternative time representation all Dequivalent to "%m / %d / %y "tm_mon, tm_mday, tm_yearrparses locale's standard 12-hour clock time (in POSIX, "%I : %M : %S %p") tm_hour, tm_min, tm_secRequivalent to "%H : %M"tm_hour, tm_minTequivalent to "%H : %M : %S"tm_hour, tm_min, tm_secpparses the locale's equivalent of a.m. or p.m.tm_hourNote: tm_isdst is not written to, and needs to be set explicitly for use with functions such as mktime
Return value
Iterator pointing one past the last character in [beg,end) that was parsed successfully.
Notes
The case-insensitive comparison for the non-whitespace non-'%' characters in the format string, the
facet of the locale provided by str is typically, but not necessarily, used.
If a parsing error is encountered, many implementations of this function leave *t completely untouched.
It's unspecified if these functions zero out the fields in *t that they do not set directly: portable programs should initialize every field to zero before calling get().
Example
Run this code
#include<iomanip>#include<iostream>#include<locale>#include<sstream>intmain(){std::istringstreamss("2026-März-12 23:45:56");ss.imbue(std::locale("de_DE.utf8"));auto&f=std::use_facet<std::time_get<char>>(ss.getloc());std::tmt{};std::strings="%Y-%b-%d %H:%M:%S";std::ios_base::iostateerr=std::ios_base::goodbit;autoret=f.get({ss},{},ss,err,&t,&s[0],&s[0]+s.size());ss.setstate(err);std::istreambuf_iterator<char>last{};if(ss){std::cout<<"Successfully parsed as "<<std::put_time(&t,"%c")<<'\n';if(ret!=last){std::cout<<"Remaining content: ";std::copy(ret,last,std::ostreambuf_iterator<char>(std::cout));}elsestd::cout<<"The input was fully consumed.";}else{std::cout<<"Parse failed.\nUnparsed string: ";std::copy(ret,last,std::ostreambuf_iterator<char>(std::cout));}std::cout<<'\n';}Output:
Successfully parsed as Sun Mar 12 23:45:56 2026 The input was fully consumed. See also
(C++11)
parses a date/time value of specified format
(function template)