std::experimental::optional::operator->, std::experimental::optional::operator*

 

C++

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

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

Ranges (ranges TS)

Special mathematical functions (special math TR)

 

Library fundamentals

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

 

std::experimental::optional

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

 

constexpr const T* operator->() const;	(1)	(library fundamentals TS)
constexpr T* operator->();	(1)	(library fundamentals TS)
constexpr const T& operator*() const&;	(2)	(library fundamentals TS)
constexpr T& operator*() &;	(2)	(library fundamentals TS)
constexpr const T&& operator*() const&&;	(2)	(library fundamentals TS)
constexpr T&& operator*() &&;	(2)	(library fundamentals TS)

Accesses the contained value.

1) Returns a pointer to the contained value.

2) Returns a reference to the contained value.

The behavior is undefined if *this does not contain a value

Parameters

(none)

Return value

Pointer or reference to the contained value.

Exceptions

(none)

Notes

This operator does not check whether the optional contains a value. If checked access is needed, value() or value_or() may be used.

Example

Run this code

#include <experimental/optional>
#include <iostream>
#include <string>
using namespace std::literals;
int main()
{
    std::experimental::optional<int> opt1 = 1;
    std::cout << *opt1 << '\n';
 
    std::experimental::optional<std::string> opt2 = "abc"s;
    std::cout << opt2->size() << '\n';
}

Output:

1
3

See also

value	returns the contained value (public member function)
value_or	returns the contained value if available, another value otherwise (public member function)