std::experimental::optional::operator bool
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                    < cpp | experimental | optional
                    
                                                            
                    | constexpr explicit operator bool() const; | (library fundamentals TS) | |
Checks whether *this is in engaged state, i.e. whether the contained value is initialized.
[edit] Parameters
(none)
[edit] Return value
true if *this is in engaged state, false otherwise.
[edit] Exceptions
noexcept specification:  
noexcept