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Learn more about: nullopt_t Struct |
nullopt_t Struct |
08/04/2019 |
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The nullopt_t type is a unique, empty type used to indicate an optional object doesn't contain a value.
The constant nullopt of type nullopt_t indicates an optional type has an uninitialized state. It can be used to initialize an optional object or compared with one.
struct nullopt_t;
inline constexpr nullopt_t nullopt{ /*implementation-defined*/ };