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

 

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C-style date and time

 

std::chrono::month

Member functions

month::month

month::operator++month::operator--

month::operator+=month::operator-=

month::operator unsigned

month::ok

Nonmember functions

operator==operator<=>

operator+operator-

operator<<

from_stream

Helper classes

formatter<std::chrono::month>

 

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

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.

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 locale

See also

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