std::experimental::nullopt

Defined in header `<experimental/optional>`
constexpr nullopt_t nullopt{/unspecified/};		(library fundamentals TS)

std::experimental::nullopt is a constant of type std::experimental::nullopt_t that is used to indicate optional type with uninitialized state.

(library fundamentals TS)

indicator of optional type with uninitialized state
(class)

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Concepts (concepts TS)
Extensions for concurrency (concurrency TS)
Special mathematical functions (special math TR)

experimental::optional
experimental::any
experimental::basic_string_view
experimental::sample
experimental::shared_ptr
experimental::weak_ptr
experimental::apply
experimental::invocation_type experimental::raw_invocation_type
experimental::search
experimental::default_searcher experimental::make_default_searcher
experimental::boyer_moore_searcher experimental::make_boyer_moore_searcher
experimental::boyer_moore_horspool_searcher experimental::make_boyer_moore_horspool_searcher
type-erased and polymorphic allocators
variable templates for type traits

Member functions
optional::optional
optional::~optional
optional::operator=
Observers
optional::operator->optional::operator*
optional::operator bool
optional::value
optional::value_or
Modifiers
optional::emplace
optional::swap
Non-member functions
operator==operator!=operator<operator<=operator>operator>=
make_optional
swap
Helper classes
hash
nullopt_t
in_place_t
bad_optional_access
Helper objects
nullopt
in_place