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std::chrono::operator<<(std::chrono::month)(3) C++ Standard Libary std::chrono::operator<<(std::chrono::month)(3)


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


Defined in header <chrono>
template <class CharT, class Traits>

std::basic_ostream<CharT, Traits>& (since C++20)

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"),

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

Return value



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.

DR Applied to Behavior as published Correct behavior
P2372R3 C++20 the given locale was used by default L is needed to use the given

See also

format stores formatted representation of the arguments
(C++20) in a new string
(function template)
std::formatter<std::chrono::month> specialization of std::formatter that formats a
(C++20) month according to the provided format
(class template specialization)