std::optional<T>::operator bool, std::optional<T>::has_value

 

C++

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Concepts library (C++20)

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Utilities library

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Utilities library

Type support (basic types, RTTI, type traits)
Dynamic memory management
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initializer_list (C++11)
bitset
hash (C++11)
integer_sequence (C++14)
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rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
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strong_order weak_order partial_order strong_equal weak_equal	strong_ordering weak_ordering partial_ordering strong_equality weak_equality	is_eqis_neqis_ltis_lteqis_gtis_gteq
common_comparison_category
Common vocabulary types
pair tuple (C++11) apply (C++17) make_from_tuple (C++17)	optional (C++17) any (C++17) variant (C++17)
Swap, forward and move
swap
exchange (C++14)
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Type operations
declval (C++11)
as_const (C++17)
launder (C++17)

 

std::optional

Member functions

optional::optional

optional::~optional

optional::operator=

Observers

optional::operator->optional::operator*

optional::operator booloptional::has_value

optional::value

optional::value_or

Modifiers

optional::emplace

optional::swap

optional::reset

Non-member functions

operator==operator!=operator<operator<=operator>operator>=

make_optional

swap

Deduction guides

Helper classes

hash

nullopt_t

in_place_t

bad_optional_access

Helper objects

nullopt

in_place

 

constexpr explicit operator bool() const noexcept;		(since C++17)
constexpr bool has_value() const noexcept;		(since C++17)

Checks whether *this contains a value.

Parameters

(none)

Return value

true if *this contains a value, false if *this does not contain a value.