std::optional::value_or
From cppreference.com
| template< class U > constexpr T value_or( U&& value ) const&; |
(since C++14) | |
| template< class U > T value_or( U&& value ) &&; |
(since C++14) | |
Returns the contained value if *this is in engaged state, otherwise returns value.
Contents |
[edit] Parameters
| value | - | the value to exchange |
| Type requirements | ||
-T must meet the requirements of CopyConstructible in order to use overload (1).
| ||
-T must meet the requirements of MoveConstructible in order to use overload (2).
| ||
-U&& must be convertible to T
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[edit] Return value
The current value if *this is in engaged state, or value otherwise.
[edit] Exceptions
Any exception thrown by the selected constructor of T.
If an exception is thrown, the exception safety guarantee is as follows:
- If *this was in engaged state, the contents of the contained value depend on the exception safety guarantee of
T's constructor. - Otherwise, the state of *this does not change. The contents of
valuedepend on the exception safety guarantee ofT's constructor.
[edit] See also
| returns the contained value (public member function) | |
