std::optional::reset

void reset();		(since C++17)

If *this contains a value, destroy that value as if by value().T::~T(). Otherwise, there are no effects.

*this does not contain a value after this call.

noexcept specification:

noexcept

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

Type support (basic types, RTTI, type traits)
Dynamic memory management
Error handling
Program utilities
Variadic functions
Date and time
Function objects
initializer_list (C++11)
bitset
hash (C++11)
Relational operators
rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
`optional`, `any` and `variant` (C++17)
optional
any
variant
in_placein_place_typein_place_indexin_place_tin_place_type_tin_place_index_t
Pairs and tuples
pair
tuple (C++11)
apply (C++17)
make_from_tuple (C++17)
piecewise_construct_t (C++11)
piecewise_construct (C++11)
integer_sequence (C++14)
Swap, forward and move
swap
exchange (C++14)
forward (C++11)
move (C++11)
move_if_noexcept (C++11)
Elementary string conversions
to_chars (C++17)
from_chars (C++17)
chars_format (C++17)
Type operations
declval (C++11)
as_const (C++17)

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
Helper classes
hash
nullopt_t
in_place_t
bad_optional_access
Helper objects
nullopt
in_place