NAME¶

std::time_get::get_year,std::time_get::do_get_year - std::time_get::get_year,std::time_get::do_get_year

Synopsis¶

Defined in header <locale>
public:

iter_type get_year( iter_type s, iter_type end, std::ios_base& str, (1)

std::ios_base::iostate& err, std::tm* t ) const;
protected:

virtual iter_type do_get_year( iter_type s, iter_type end, std::ios_base& str, (2)

std::ios_base::iostate& err, std::tm* t ) const;

1) Public member function, calls the protected virtual member function do_get_year
of the most derived class.
2) Reads successive characters from the sequence [beg, end) and parses out the year
using some implementation-defined format. Depending on the locale, two-digit years
may be accepted, and it is implementation-defined which century they belong to.

The parsed year is stored in the std::tm structure field t->tm_year.

If the end iterator is reached before a valid year 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 year.

Notes¶

For two-digit input values, many implementations use the same parsing rules as the
conversion specifier '%y' as used by std::get_time, std::time_get::get(), and the
POSIX function strptime(): two-digit integer is expected, the values in the range
[69, 99] results in values 1969 to 1999, range [00, 68] results in 2000 to 2068.
Four-digit inputs are typically accepted as-is.

If a parsing error is encountered, most implementations of this function leave *t
unmodified.

Example¶

// Run this code

#include <iostream>
#include <iterator>
#include <locale>
#include <sstream>

void try_get_year(const std::string& s)
{
std::cout << "Parsing the year 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::time_get<char> const& facet = std::use_facet<std::time_get<char>>(str.getloc());
std::istreambuf_iterator<char> ret = facet.get_year({str}, {}, str, err, &t);
str.setstate(err);
std::istreambuf_iterator<char> last{};

if (str)
{
std::cout << "Successfully parsed, year is " << 1900 + t.tm_year;

if (ret != last)
{
std::cout << " Remaining content: ";
std::copy(ret, last, std::ostreambuf_iterator<char>(std::cout));
}
else
std::cout << " the input was fully consumed";
}
else
{
std::cout << "Parse failed. Unparsed string: ";
std::copy(ret, last, std::ostreambuf_iterator<char>(std::cout));
}

std::cout << '\n';
}

int main()
{
std::locale::global(std::locale("en_US.utf8"));
try_get_year("13");
try_get_year("2013");

std::locale::global(std::locale("ja_JP.utf8"));
try_get_year("2013年");
}

Possible output:¶

Parsing the year out of '13' in the locale en_US.utf8
Successfully parsed, year is 2013 the input was fully consumed
Parsing the year out of '2013' in the locale en_US.utf8
Successfully parsed, year is 2013 the input was fully consumed
Parsing the year out of '2013年' in the locale ja_JP.utf8
Successfully parsed, year is 2013 Remaining content: 年

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 year
end iterator has not been read

See also¶

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