Experimental library header <experimental/optional> - cppreference.com (original) (raw)
This header is part of the Library Fundamentals TS (v1, v2).
Contents
[edit] Classes
| Name | Description |
|---|---|
| optional(library fundamentals TS) | a wrapper that may or may not hold an object (class template) [edit] |
| bad_optional_access(library fundamentals TS) | exception indicating checked access to an optional that doesn't contain a value (class) [edit] |
| in_place_t(library fundamentals TS) | disambiguation tag type for in-place construction of optional types (class) [edit] |
| std::hashstd::experimental::optional | specializes the std::hash algorithm (class template specialization) [edit] |
| nullopt_t(library fundamentals TS) | indicator of optional type with uninitialized state (class) [edit] |
[edit] Functions
| Comparison | |
|---|---|
| operator==operator!=operator<operator<=operator>operator>= | compares optional objects (function template) [edit] |
| Specialized algorithms | |
| std::swap(std::experimental::optional) | specializes the std::swap algorithm (function) [edit] |
| make_optional | creates an optional object (function template) [edit] |
| Hash support |
[edit] Synopsis
namespace std { namespace experimental { inline namespace fundamentals_v1 { // 5.4, optional for object types template 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 constexpr bool operator==(const optional&, const optional&); template constexpr bool operator!=(const optional&, const optional&); template constexpr bool operator<(const optional&, const optional&); template constexpr bool operator>(const optional&, const optional&); template constexpr bool operator<=(const optional&, const optional&); template constexpr bool operator>=(const optional&, const optional&); // 5.9, Comparison with nullopt template constexpr bool operator==(const optional&, nullopt_t) noexcept; template constexpr bool operator==(nullopt_t, const optional&) noexcept; template constexpr bool operator!=(const optional&, nullopt_t) noexcept; template constexpr bool operator!=(nullopt_t, const optional&) noexcept; template constexpr bool operator<(const optional&, nullopt_t) noexcept; template constexpr bool operator<(nullopt_t, const optional&) noexcept; template constexpr bool operator<=(const optional&, nullopt_t) noexcept; template constexpr bool operator<=(nullopt_t, const optional&) noexcept; template constexpr bool operator>(const optional&, nullopt_t) noexcept; template constexpr bool operator>(nullopt_t, const optional&) noexcept; template constexpr bool operator>=(const optional&, nullopt_t) noexcept; template constexpr bool operator>=(nullopt_t, const optional&) noexcept; // 5.10, Comparison with T template constexpr bool operator==(const optional&, const T&); template constexpr bool operator==(const T&, const optional&); template constexpr bool operator!=(const optional&, const T&); template constexpr bool operator!=(const T&, const optional&); template constexpr bool operator<(const optional&, const T&); template constexpr bool operator<(const T&, const optional&); template constexpr bool operator<=(const optional&, const T&); template constexpr bool operator<=(const T&, const optional&); template constexpr bool operator>(const optional&, const T&); template constexpr bool operator>(const T&, const optional&); template constexpr bool operator>=(const optional&, const T&); template constexpr bool operator>=(const T&, const optional&); // 5.11, Specialized algorithms template void swap(optional&, optional&) noexcept(see below); template constexpr optional make_optional(T&&); } // namespace fundamentals_v1 } // namespace experimental // 5.12, Hash support template struct hash; template struct hash<experimental::optional>; } // namespace std