std::chrono::operator<<(std::chrono::weekday)
Defined in header <chrono> |
||
|---|---|---|
template< class CharT, class Traits > std::basic_ostream<CharT, Traits>& operator<<( std::basic_ostream<CharT, Traits>& os, const std::chrono::weekday& wd ); |
(since C++20) |
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.
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
|
(C++20)
|
stores formatted representation of the arguments in a new string (function template) |
|
(C++20)
|
specialization of std::formatter that formats a weekday according to the provided format (class template specialization) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/chrono/weekday/operator_ltlt
