Experimental library header <experimental/optional>
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Experimental library headers
Execution P2300
Filesystem TS
Parallelism TS (v1, v2)
experimental/algorithmexperimental/execution_policyexperimental/exception_list Library Fundamentals TS (v1, v2, v3)
experimental/algorithmexperimental/arrayexperimental/chronoexperimental/dequeexperimental/forward_listexperimental/futureexperimental/iteratorexperimental/listexperimental/mapexperimental/memoryexperimental/numeric <experimental/optional>
experimental/propagate_constexperimental/randomexperimental/ratioexperimental/regexexperimental/scopeexperimental/setexperimental/source_locationexperimental/stringexperimental/system_errorexperimental/tupleexperimental/type_traitsexperimental/unordered_mapexperimental/unordered_setexperimental/utilityexperimental/vector Concurrency TS
experimental/atomicexperimental/barrierexperimental/futureexperimental/latch Ranges TS
Coroutines TS
experimental/coroutine Networking TS
experimental/bufferexperimental/executorexperimental/internetexperimental/io_context Reflection TS
This header is part of the Library Fundamentals TS (v1, v2).
Contents
[edit] Classes
Name
Description
(library fundamentals TS)
(class) [edit]
(library fundamentals TS)
(class) [edit]
[edit] Functions
Comparison
Specialized algorithms
Hash support
[edit] Synopsis
namespace std { namespace experimental { inline namespace fundamentals_v1 { // 5.4, optional for object types template <class T> class optional; // 5.5, In-place construction struct in_place_t{}; constexpr in_place_t in_place{}; // 5.6, Disengaged state indicator struct nullopt_t{see below}; constexpr nullopt_t nullopt(unspecified); // 5.7, Class bad_optional_access class bad_optional_access; // 5.8, Relational operators template <class T> constexpr bool operator==(const optional<T>&, const optional<T>&); template <class T> constexpr bool operator!=(const optional<T>&, const optional<T>&); template <class T> constexpr bool operator<(const optional<T>&, const optional<T>&); template <class T> constexpr bool operator>(const optional<T>&, const optional<T>&); template <class T> constexpr bool operator<=(const optional<T>&, const optional<T>&); template <class T> constexpr bool operator>=(const optional<T>&, const optional<T>&); // 5.9, Comparison with nullopt template <class T> constexpr bool operator==(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator==(nullopt_t, const optional<T>&) noexcept; template <class T> constexpr bool operator!=(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator!=(nullopt_t, const optional<T>&) noexcept; template <class T> constexpr bool operator<(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator<(nullopt_t, const optional<T>&) noexcept; template <class T> constexpr bool operator<=(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator<=(nullopt_t, const optional<T>&) noexcept; template <class T> constexpr bool operator>(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator>(nullopt_t, const optional<T>&) noexcept; template <class T> constexpr bool operator>=(const optional<T>&, nullopt_t) noexcept; template <class T> constexpr bool operator>=(nullopt_t, const optional<T>&) noexcept; // 5.10, Comparison with T template <class T> constexpr bool operator==(const optional<T>&, const T&); template <class T> constexpr bool operator==(const T&, const optional<T>&); template <class T> constexpr bool operator!=(const optional<T>&, const T&); template <class T> constexpr bool operator!=(const T&, const optional<T>&); template <class T> constexpr bool operator<(const optional<T>&, const T&); template <class T> constexpr bool operator<(const T&, const optional<T>&); template <class T> constexpr bool operator<=(const optional<T>&, const T&); template <class T> constexpr bool operator<=(const T&, const optional<T>&); template <class T> constexpr bool operator>(const optional<T>&, const T&); template <class T> constexpr bool operator>(const T&, const optional<T>&); template <class T> constexpr bool operator>=(const optional<T>&, const T&); template <class T> constexpr bool operator>=(const T&, const optional<T>&); // 5.11, Specialized algorithms template <class T> void swap(optional<T>&, optional<T>&) noexcept(see below); template <class T> constexpr optional<see below> make_optional(T&&); } // namespace fundamentals_v1 } // namespace experimental // 5.12, Hash support template <class T> struct hash; template <class T> struct hash<experimental::optional<T>>; } // namespace std