std::chrono::operator<<(std::chrono::weekday)

template< class CharT, class Traits >
std::basic_ostream<CharT, Traits>&
    operator<<( std::basic_ostream<CharT, Traits>& os, const std::chrono::weekday& wd );

If !wd.ok(), inserts wd.c_encoding() followed by " is not a valid weekday" into os. Otherwise, forms a std::basic_string<CharT> s consisting of the abbreviated weekday name for the weekday represented by wd, determined using the locale associated with os, and inserts s into os.

Equivalent to

return os << (wd.ok() ?
std::format(os.getloc(), STATICALLY_WIDEN<CharT>("{:L%a}"), wd) :
std::format(os.getloc(), STATICALLY_WIDEN<CharT>("{} is not a valid weekday"),
wd.c_encoding()));

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

Return value

os

Example

Defect reports

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

See also