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| Member functions | ||||
time_get::get_weekdaytime_get::do_get_weekday | ||||
Defined in header <locale> | ||
public: iter_type get_weekday( iter_type beg, iter_type end,std::ios_base& str, | (1) | |
protected: virtual iter_type do_get_weekday( iter_type beg, iter_type end,std::ios_base& str, | (2) | |
do_get_weekday of the most derived class.[beg, end) and parses out the weekday name (possibly abbreviated), using the default format for weekdays expected by this locale, which is the same format as"%a" as used by the functionsstd::get_time,time_get::get, and the POSIX functionstrptime().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 is not expected, in which case parsing fails even if the first few characters were a valid abbreviation.
The parsed weekday is stored in thestd::tm fieldt->tm_wday.
If the end iterator is reached before a valid weekday name is read, the function setsstd::ios_base::eofbit inerr. If a parsing error is encountered, the function setsstd::ios_base::failbit inerr.
Contents |
| 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 orstd::collate to compare strings |
| err | - | stream error flags object that is modified by this function to indicate errors |
| t | - | pointer to thestd::tm object that will hold the result of this function call |
Iterator pointing one past the last character in[beg, end) that was recognized as a part of a valid weekday name.
This function is usually case-insensitive.
If a parsing error is encountered, most implementations of this function leave*t unmodified.
#include <initializer_list>#include <iostream>#include <iterator>#include <locale>#include <sstream>#include <string_view> void try_get_wday(std::string_view s){std::cout<<"Parsing the weekday out of '"<< s<<"' in the locale "<<std::locale().name()<<'\n';std::istringstream str{s.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_weekday({str},{}, str, err,&t); str.setstate(err);std::istreambuf_iterator<char> last{}; if(str){std::cout<<"Successfully parsed, weekday number is "<< t.tm_wday; if(ret!= last){std::cout<<" Remaining content: ";std::copy(ret, last,std::ostreambuf_iterator<char>(std::cout));}elsestd::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';} void demo(std::string_view locale_name,std::initializer_list<std::string_view>&& data){try{std::locale::global(std::locale(locale_name.data()));}catch(std::runtime_errorconst& ex){std::cout<<"Cannot setup locale: "<< locale_name<<"\n""Exception: "<< ex.what()<<'\n';return;} for(std::string_viewconst weekday: data) try_get_wday(weekday);} int main(){ demo("lt_LT.utf8",{"Št","Šeštadienis"}); demo("en_US.utf8",{"SATELLITE"}); demo("ja_JP.utf8",{"土曜日"});}
Possible output:
Parsing the weekday out of 'Št' in the locale lt_LT.utf8Successfully parsed, weekday number is 6 the input was fully consumedParsing the weekday out of 'Šeštadienis' in the locale lt_LT.utf8Successfully parsed, weekday number is 6 the input was fully consumedParsing the weekday out of 'SATELLITE' in the locale en_US.utf8Successfully parsed, weekday number is 6 Remaining content: ELLITEParsing the weekday out of '土曜日' in the locale ja_JP.utf8Successfully parsed, weekday number is 6 the input was fully consumed
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 | setseofbit if a valid weekday name has not been read |
(C++11) | parses a date/time value of specified format (function template)[edit] |
