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std::time_get<CharT,InputIt>::get_year, std::time_get<CharT,InputIt>::do_get_year

Defined in header <locale>

Defined in header `<locale>`
public: iter_type get_year( iter_type s, iter_type end, std::ios_base& str, std::ios_base::iostate& err, std::tm* t ) const;	(1)
protected: virtual iter_type do_get_year( iter_type s, iter_type end, std::ios_base& str, std::ios_base::iostate& err, std::tm* t ) const;	(2)

public:
iter_type get_year( iter_type s, iter_type end, std::ios_base& str,
                    std::ios_base::iostate& err, std::tm* t ) const;

(1)

protected:
virtual iter_type do_get_year( iter_type s, iter_type end, std::ios_base& str,
                               std::ios_base::iostate& err, std::tm* t ) const;

(2)

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 2000-2068. Four-digit inputs are typically accepted as-is.

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

Example

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