std::time_get<CharT,InputIt>::get_date, std::time_get<CharT,InputIt>::do_get_date
From cppreference.com
| Defined in header <locale>
|
||
| public: iter_type get_date( iter_type beg, iter_type end, std::ios_base& str, |
(1) | |
| protected: virtual iter_type do_get_date( iter_type beg, iter_type end, std::ios_base& str, |
(2) | |
1) Public member function, calls the protected virtual member function
do_get_date of the most derived class.2) Reads successive characters from the sequence
[beg, end) and parses out the calendar date value using the default format expected by this locale, which is determined as
| date_order() | Format |
|---|---|
no_order
|
"%m/%d/%y" |
dmy
|
"%d/%m/%y" |
mdy
|
"%m/%d/%y" |
ymd
|
"%y/%m/%d" |
ydm
|
"%y/%d/%m" |
The parsed date is stored in the corresponding fields of the std::tm structure pointed to by the argument t.
If the end iterator is reached before a valid date is read, the function sets std::ios_base::eofbit in err. If a parsing error is encountered, the function sets std::ios_base::failbit in err.
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. std::ctype to skip whitespace or std::collate to compare strings |
| err | - | stream error flags object that is modified by this function to indicate errors |
| t | - | pointer to the std::tm object that will hold the result of this function call |
Return value
Iterator pointing one past the last character in [beg, end) that was recognized as a part of a valid date.
Notes
For the alphabetic components of the default date format (if any), this function is usually case-insensitive.
If a parsing error is encountered, most implementations of this function leave *t unmodified.
The implementation may support other date formats besides the ones required by the standard.
Example
Run this code
#include <ctime> #include <iostream> #include <iterator> #include <locale> #include <sstream> void try_get_date(const std::string& s) { std::cout << "Parsing the date out of '" << s << "' in the locale " << std::locale().name() << '\n'; std::istringstream str(s); std::ios_base::iostate err = std::ios_base::goodbit; std::tm t; const std::time_get<char>& facet = std::use_facet<std::time_get<char>>(str.getloc()); std::istreambuf_iterator<char> ret = facet.get_date({str}, {}, str, err, &t); str.setstate(err); if (str) { std::cout << "Day: " << t.tm_mday << ' ' << "Month: " << t.tm_mon + 1 << ' ' << "Year: " << t.tm_year + 1900 << '\n'; } else { std::cout << "Parse failed. Unparsed string: "; std::copy(ret, {}, std::ostreambuf_iterator<char>(std::cout)); std::cout << '\n'; } } int main() { std::locale::global(std::locale("en_US.utf8")); try_get_date("02/01/2013"); try_get_date("02-01-2013"); std::locale::global(std::locale("ja_JP.utf8")); try_get_date("2013年02月01日"); }
Output:
Parsing the date out of '02/01/2013' in the locale en_US.utf8 Day: 1 Month: 2 Year: 2013 Parsing the date out of '02-01-2013' in the locale en_US.utf8 Parse failed. Unparsed string: -01-2013 Parsing the date out of '2013年02月01日' in the locale ja_JP.utf8 Day: 1 Month: 2 Year: 2013
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 248 | C++98 | eofbit was not set upon reaching the end iterator
|
sets eofbit if a valid date has not been read
|
| LWG 461 | C++98 | do_get_date needed to parse localized date representation
|
parses with the format determined by date_order() |
See also
| (C++11) |
parses a date/time value of specified format (function template) |