std::chrono:: operator<< (std::chrono::year_month_day)

Defined in header <chrono>
template < class CharT, class Traits > std:: basic_ostream < CharT, Traits > & operator << ( std:: basic_ostream < CharT, Traits > & os, const std:: chrono :: year_month_day & ymd ) ;		(since C++20)

Outputs a textual representation of ymd into the stream os . This first forms a std:: basic_string < CharT > s consisting of a textual representation of the date in the format yyyy-mm-dd (same as the one output by formatter with the %F specifier). Then, if ! ymd. ok ( ) , appends " is not a valid date" to s . Inserts s into os .

Equivalent to

return os << ( ymd. ok ( ) ?
std:: format ( STATICALLY_WIDEN < CharT > ( "{:%F}" ) , ymd ) :
std:: format ( STATICALLY_WIDEN < CharT > ( "{:%F} is not a valid date" ) , ymd ) ) ;

where STATICALLY_WIDEN < CharT > ( "..." ) is "..." if CharT is char , and L "..." if CharT is wchar_t .

Return value

os

Example

This section is incomplete Reason: no example

See also

format (C++20)	stores formatted representation of the arguments in a new string (function template)
std::formatter <std::chrono::year_month_day> (C++20)	formatting support for year_month_day (class template specialization)