std::time_get::get

public:
iter_type get(iter_type beg, iter_type end, std::ios_base& str,
              std::ios_base::iostate& err, std::tm* t,
              const char_type* fmtbeg, const char_type* fmtend) const;

protected:
virtual iter_type do_get(iter_type neg, iter_type end, std::ios_base& str,
                         std::ios_base::iostate& err, std::tm *t,
                         char format, char modifier) const;

In the body of the loop, the following steps take place:

First, clears the error bits in err by executing err = std::ios_base::goodbit. Then reads characters from the input sequence [beg, end) that are expected by the std::time_get format specifier formed by combining '%', modifier (if not '\0'), and format. If the characters do not combine to form a valid conversion specifier, sets failbit in err. If the end of the input stream is reached after reading a character, sets eofbit in err. If the input string was parsed successfully, updates the corresponding fields of *t. For complex conversion specifiers, such as '%x' or '%c', or the directives that use the modifiers 'E' and 'O', the function may fail to determine some of the values to store in *t. In such case, it sets eofbit in err and leaves these fields in unspecified state.

Parameters

Return value

Iterator pointing one past the last character in [beg, end) that was parsed successfully.

Notes

The case-insensitive comparison for the non-whitespace non-'%' characters in the format string, the std::collate facet of the locale provided by str is typically, but not necessarily, used.

If a parsing error is encountered, many implementations of this function leave *t completely untouched.

It's unspecified if these functions zero out the fields in *t that they do not set directly: portable programs should initialize every field to zero before calling get().

Example

#include <iostream>
#include <sstream>
#include <locale>
#include <iomanip>
 
int main()
{
    std::istringstream ss("2011-Februar-18 23:12:34");
    ss.imbue(std::locale("de_DE.utf8"));
 
    auto& f = std::use_facet<std::time_get<char>>(std::locale("de_DE.utf8"));
    std::tm t{};
    std::string s = "%Y-%b-%d %H:%M:%S";
    std::ios_base::iostate err = std::ios_base::goodbit;
    std::istreambuf_iterator<char> ret = f.get(std::istreambuf_iterator<char>(ss),
                                               std::istreambuf_iterator<char>(),
                                               ss, err, &t, &s[0], &s[0] + s.size());
    ss.setstate(err);
 
    if(ss) {
        std::cout << "Successfully parsed as " << std::put_time(&t, "%c");
        if(ret != std::istreambuf_iterator<char>()) {
            std::cout << " Remaining content: ";
            std::copy(ret, std::istreambuf_iterator<char>(),
                           std::ostreambuf_iterator<char>(std::cout));
        } else {
                std::cout << " The input was fully consumed";
        }
    } else {
            std::cout << "Parse failed. Unparsed string: ";
            std::copy(ret, std::istreambuf_iterator<char>(),
                           std::ostreambuf_iterator<char>(std::cout));
    }
    std::cout << '\n';
}

Successfully parsed, as Sun Feb 18 23:12:34 2011 The input was fully consumed

See also