std::chrono::operator<<(std::chrono::month)

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

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

Equivalent to.

return os << (m.ok() ?
std::format(os.getloc(), STATICALLY_WIDEN<CharT>("{:L%b}"), m) :
std::format(os.getloc(), STATICALLY_WIDEN<CharT>("{} is not a valid month"), unsigned(m)));

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

Return value

os.

Notes

This operator<< is primarily intended for debugging use. For control over formatting, use std::format.

Defect reports

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

See also