std::chrono::month_weekday_last:: ok

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std::chrono::month_weekday_last
constexpr bool ok ( ) const noexcept ;
(since C++20)

Checks if the contained month and weekday_last objects are valid.

Return value

month ( ) . ok ( ) && weekday_last ( ) . ok ( )

Example

Run this code 
#include <chrono>
#include <iostream>
 
int main()
{
    std::cout << std::boolalpha;
 
    auto mwdl{std::chrono::March/std::chrono::Wednesday[std::chrono::last]};
    std::cout << (mwdl.ok()) << ' ';
    mwdl = {std::chrono::month(3)/std::chrono::weekday(42)[std::chrono::last]}; 
    std::cout << (mwdl.ok()) << '\n';
}

Output: 

true false
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