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value_or() requires that U is convertible to T

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Due to Vladimir Batov.
This commit is contained in:
Andrzej Krzemienski
2014-06-14 22:49:37 +02:00
parent 8fc2901fad
commit 31c9119266
9 changed files with 66 additions and 17 deletions
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doc/20_reference.qbk
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@ -908,7 +908,7 @@ __SPACE__
[: `template<class U> T optional<T>::value_or(U && v) const& ;`]
[: `template<class U> T optional<T>::value_or(U && v) && ;`]
* [*Requires:] `T` is CopyConstructible.
* [*Requires:] `T` is __COPY_CONSTRUCTIBLE__ and `U &&` is convertible to `T`.
* [*Returns:] First overload: `bool(*this) ? **this : static_cast<T>(forward<U>(v))`. second overload: `bool(*this) ? std::move(**this) : static_cast<T>(forward<U>(v))`.
* [*Throws:] Any exception thrown by the selected constructor of `T`.
* [*Notes:] On compilers that do not support ref-qualifiers on member functions these three overloads are replaced with the classical two: a `const` and non-`const` member functions. On compilers without rvalue reference support the type of `v` becomes `U const&`.