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std::time_get<CharT,InputIt>::get_monthname, std::time_get<CharT,InputIt>::do_get_monthname

Defined in header <locale>

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

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

(1)

protected:
virtual iter_type do_get_monthname( iter_type beg, 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_monthname of the most derived class.

2) Reads successive characters from the sequence [beg, end) and parses out the month name (possibly abbreviated), using the default format for month names expected by this locale, which is the same format as "%b" as used by the functions std::get_time, time_get::get, and the POSIX function strptime().

If it finds abbreviated name, followed by the characters that are valid for the full name, it continues reading until it consumes all the characters for the full name or finds a character that isn't expected, in which case parsing fails even if the first few characters were a valid abbreviation.

The parsed month is stored in the std::tm field t->tm_mon.

If the end iterator is reached before a valid month name 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 month name.

Notes

This function is usually case-insensitive.

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

Example

#include <ctime>
#include <iostream>
#include <iterator>
#include <locale>
#include <sstream>
#include <string_view>
 
void try_get_mon(std::string_view locale_name, std::string_view source)
{
    try
    {
        std::locale::global(std::locale(locale_name.data()));
    }
    catch(std::runtime_error const& ex)
    {
        std::cout << "Cannot setup locale: " << locale_name << "\n"
                     "Exception: " << ex.what() << '\n';
        return;
    }
 
    std::cout << "Parsing the month out of '" << source
              << "' in the locale " << std::locale().name() << '\n';
    std::istringstream str{source.data()};
    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_monthname({str}, {}, str, err, &t);
    str.setstate(err);
    std::istreambuf_iterator<char> last{};
 
    if (str)
    {
        std::cout << "Successfully parsed, month number is " << t.tm_mon;
 
        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()
{
    try_get_mon("ja_JP.utf8", "2月");
    try_get_mon("th_TH.utf8", "กุมภาพันธ์");
    try_get_mon("el_GR.utf8", "Φεβ");
    try_get_mon("el_GR.utf8", "Φεβρουάριος");
    try_get_mon("en_US.utf8", "Febrile");
}

Possible output:

Parsing the month out of '2月' in the locale ja_JP.utf8
Successfully parsed, month number is 1. The input was fully consumed
Parsing the month out of 'กุมภาพันธ์' in the locale th_TH.utf8
Successfully parsed, month number is 1. The input was fully consumed
Parsing the month out of 'Φεβ' in the locale el_GR.utf8
Successfully parsed, month number is 1. The input was fully consumed
Parsing the month out of 'Φεβρουάριος' in the locale el_GR.utf8
Successfully parsed, month number is 1. The input was fully consumed
Parsing the month out of 'Febrile' in the locale en_US.utf8
Parse failed. Unparsed string: ile

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.