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
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"

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 <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 sets eofbit if a valid date
end iterator has not been read
LWG 461 C++98 do_get_date needed to parse localized parses with the format
date representation determined by date_order()

See also¶

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