std::chrono::operator<<(std::chrono::weekday) - cppreference.com (original) (raw)
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.
[edit] Return value
os
[edit] Example
[edit] 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 |