106 lines
5.8 KiB
Plaintext
106 lines
5.8 KiB
Plaintext
[/
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Boost.Optional
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Copyright (c) 2015 - 2018 Andrzej Krzemienski
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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]
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[section:relnotes Release Notes]
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[heading Boost Release 1.69]
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* Remove deprecation mark from `reset()` method (without arguments).
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* Fixed [@https://github.com/boostorg/optional/issues/59 issue #59].
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* Fixed bug with initialization of certain wrapper types in clang with -std=c++03. See [@https://github.com/boostorg/optional/pull/64 pr #64].
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[heading Boost Release 1.68]
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* Added member function `has_value()` for compatibility with `std::optional` ([@https://github.com/boostorg/optional/issues/52 issue #52]).
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* Added member function `map()` for transforming `optional<T>` into `optional<U>` using a function of type `T -> U`.
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* Added member function `flat_map()` for transforming `optional<T>` into `optional<U>` using a function of type `T -> optonal<U>`.
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[heading Boost Release 1.67]
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* Fixed [@https://github.com/boostorg/optional/issues/46 issue #46].
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* Fixed `-Wzero-as-null-pointer-constant` warnings.
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[heading Boost Release 1.66]
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* On newer compilers `optional` is now trivially-copyable for scalar `T`s. This uses a different storage (just `T` rather than `aligned_storage`). We require the compiler to support defaulted functions.
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* Changed the implementation of `operator==` to get rid of the `-Wmaybe-uninitialized` false-positive warning from GCC.
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[heading Boost Release 1.63]
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* Added two new in-place constructors. They work similarly to `emplace()` functions: they initialize the contained value by perfect-forwarding the obtained arguments. One constructor always initializes the contained value, the other based on a boolean condition.
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* Syntax `o = {}` now correctly un-initializes optional, just like in `std::optional`.
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* Fixed [@https://svn.boost.org/trac/boost/ticket/12203 Trac #12203].
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* Fixed [@https://svn.boost.org/trac/boost/ticket/12563 Trac #12563].
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[heading Boost Release 1.62]
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* Fixed [@https://svn.boost.org/trac/boost/ticket/12179 Trac #12179].
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[heading Boost Release 1.61]
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* Now `boost::optional` is specialized for reference parameters. This addresses a couple of issues:
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* the `sizeof` of optional reference is that of a pointer,
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* some bugs connected to copying optional references are gone,
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* all run-time bugs caused by incorrect reference binding on some compilers are now turned into compile-time errors,
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* you can swap optional references: it is like swapping pointers: shalow, underlying objects are not affected,
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* optional references to abstract types work.
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* Documented nested typedefs ([@https://svn.boost.org/trac/boost/ticket/5193 Trac #5193]).
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* Made the perfect-forwarding constructor SFINAE-friendly, which fixes [@https://svn.boost.org/trac/boost/ticket/12002 Trac #12002]. However, this only works in the newer platforms that correctly implement C++11 `<type_traits>`.
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* Fixed [@https://svn.boost.org/trac/boost/ticket/10445 Trac #10445].
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[heading Boost Release 1.60]
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* Changed the implementation of `boost::none` again. Now it is a const object with internal linkage (as any other tag). This fixes [@https://svn.boost.org/trac/boost/ticket/11203 Trac #11203].
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[heading Boost Release 1.59]
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* For C++03 compilers, added 0-argument overload for member function `emplace()`, and therewith removed the dependency on `<boost/utility/in_place_factory.hpp>`.
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* Fixed [@https://svn.boost.org/trac/boost/ticket/11241 Trac #11241].
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[heading Boost Release 1.58]
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* `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.
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* 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].
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* IOStream operators are now mentioned in documentation.
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* 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].
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* 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]).
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* Value accessors now work correctly on rvalues of `optional<T&>` ([@https://svn.boost.org/trac/boost/ticket/10839 Trac #10839]).
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[heading Boost Release 1.57]
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* [@https://github.com/boostorg/optional/pull/9 Git pull #9]: ['"Supply `<string>` to fix C++03 compile error on `logic_error("...")`"].
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[heading Boost Release 1.56]
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* Added support for rvalue references. Now `optional<T>` works with moveable but non-copyable `T`'s,
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* Improved `swap` (now uses move operations),
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* Added function `emplace()`. This is the last of the requests from [@https://svn.boost.org/trac/boost/ticket/1841 Trac #1841],
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* `optional` is moveable, including conditional `noexcept` specifications, which make it `move_if_noexcept`-friendly,
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* Using explicit operator bool() on platforms that support it ([@https://svn.boost.org/trac/boost/ticket/4227 Trac #4227]) (breaking change),
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* Forward declaration of `operator<<(ostream&, optional const&)` to prevent inadvertent incorrect serialization of optional objects,
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* Removed deprecated function `reset()` from examples ([@https://svn.boost.org/trac/boost/ticket/9005 Trac #9005]),
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* Equality comparison with `boost::none` does not require that `T` be EqualityComparable,
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* Optional rvalue references are explicitly disallowed,
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* Binding temporaries to optional references is explicitly disallowed (breaking change),
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* More ways to access the contained value, functions `value()`, `value_or()`, `value_or_eval()`,
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* Updated and reorganized documentation, added tutorial and quick guide sections.
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[endsect][/ relnotes]
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