std::time_get<CharT,InputIt>:: get_year, std::time_get<CharT,InputIt>:: do_get_year
Defined in header
<locale>
|
||
public
:
iter_type get_year
(
iter_type s, iter_type end,
std::
ios_base
&
str,
|
(1) | |
protected
:
virtual
iter_type do_get_year
(
iter_type s, iter_type end,
std::
ios_base
&
str,
|
(2) | |
do_get_year
of the most derived class.
[
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
#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 end iterator
|
sets
eofbit
if a valid year has not been read
|
See also
(C++11)
|
parses a date/time value of specified format
(function template) |