std::time_get::get_date,std::time_get::do_get_date(3)

NAME
std::time_get::get_date,std::time_get::do_get_date - std::time_get::get_date,std::time_get::do_get_date

Synopsis
   Defined in header <locale>
   public:
   iter_type get_date( iter_type beg, iter_type end, std::ios_base& str, (1)
   std::ios_base::iostate& err, std::tm* t ) const;
   protected:
   virtual iter_type do_get_date( iter_type beg, iter_type end, std::ios_base& (2)
   str,
   std::ios_base::iostate& err, std::tm* t ) const;
   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 the
   same format as
   "%x" (until C++11)
   "%d/%m/%y", "%m/%d/%y", "%y/%m/%d", and "%y/%d/%m", depending on (since C++11)
   date_order()
   as used by the functions std::get_time(), get(), and the POSIX function strptime()
   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 <iostream>
 #include <locale>
 #include <sstream>
 #include <iterator>
 #include <ctime>
 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;
     std::istreambuf_iterator<char> ret =
         std::use_facet<std::time_get<char>>(str.getloc()).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

See also
   get_time parses a date/time value of specified format
   (C++11) (function template)