std::variant_npos

 

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std::variant

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variant_npos

 

Defined in header <variant>
inline constexpr std::size_t variant_npos = -1;		(since C++17)

This is a special value equal to the largest value representable by the type std::size_t, used as the return type of index() when valueless_by_exception() is true

See also

index	returns the zero-based index of the alternative held by the variant (public member function)
valueless_by_exception	checks if the variant is in the invalid state (public member function)