| [/ |
| Boost.Optional |
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| Copyright (c) 2015 Andrzej Krzemienski |
| |
| Distributed under the Boost Software License, Version 1.0. |
| (See accompanying file LICENSE_1_0.txt or copy at |
| http://www.boost.org/LICENSE_1_0.txt) |
| ] |
| |
| |
| [section:relnotes Release Notes] |
| |
| [heading Boost Release 1.58] |
| |
| * `boost::none_t` is no longer convertible from literal `0`. This avoids a bug where `optional<rational<int>> oi = 0;` would initialize an optional object with no contained value. |
| * Improved the trick that prevents streaming out `optional` without header `optional_io.hpp` by using safe-bool idiom. This addresses [@https://svn.boost.org/trac/boost/ticket/10825 Trac #10825] |
| * IOStream operators are now mentioned in documentation. |
| * Added a way to manually disable move semantics: just define macro `BOOST_OPTIONAL_CONFIG_NO_RVALUE_REFERENCES`. This can be used to work around [@https://svn.boost.org/trac/boost/ticket/10399 Trac #10399] |
| * It is no longer possible to assign `optional<U>` to `optional<T>` when `U` is not assignable or convertible to `T` ([@https://svn.boost.org/trac/boost/ticket/11087 Trac #11087]). |
| * Value accessors now work correctly on rvalues of `optional<T&>` ([@https://svn.boost.org/trac/boost/ticket/10839 Trac #10839]). |
| |
| |
| [heading Boost Release 1.57] |
| |
| * [@https://github.com/boostorg/optional/pull/9 Git pull #9]: ['"Supply `<string>` to fix C++03 compile error on `logic_error("...")`"]. |
| |
| |
| [heading Boost Release 1.56] |
| |
| * Added support for rvalue references. Now `optional<T>` works with moveable but non-copyable `T`'s, |
| * Improved `swap` (now uses move operations), |
| * Added function `emplace()`. This is the last of the requests from [@https://svn.boost.org/trac/boost/ticket/1841 Trac #1841], |
| * `optional` is moveable, including conditional `noexcept` specifications, which make it `move_if_noexcept`-friendly, |
| * Using explicit operator bool() on platforms that support it ([@https://svn.boost.org/trac/boost/ticket/4227 Trac #4227]) (breaking change), |
| * Forward declaration of `operator<<(ostream&, optional const&)` to prevent inadvertent incorrect serialization of optional objects, |
| * Removed deprecated function `reset()` from examples ([@https://svn.boost.org/trac/boost/ticket/9005 Trac #9005]), |
| * Equality comparison with `boost::none` does not require that `T` be EqualityComparable, |
| * Optional rvalue references are explicitly disallowed, |
| * Binding temporaries to optional references is explicitly disallowed (breaking change), |
| * More ways to access the contained value, functions `value()`, `value_or()`, `value_or_eval()`, |
| * Updated and reorganized documentation, added tutorial and quick guide sections. |
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| [endsect][/ relnotes] |
