ceph/src/boost/libs/optional/doc/91_relnotes.qbk

   1 [/
   2     Boost.Optional
   3
   4     Copyright (c) 2015, 2016 Andrzej Krzemienski
   5
   6     Distributed under the Boost Software License, Version 1.0.
   7     (See accompanying file LICENSE_1_0.txt or copy at
   8     http://www.boost.org/LICENSE_1_0.txt)
   9 ]
  10
  11
  12 [section:relnotes Release Notes]
  13
  14 [heading Boost Release 1.63]
  15 * 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.
  16 * Fixed [@https://svn.boost.org/trac/boost/ticket/12203 Trac #12203].
  17
  18
  19 [heading Boost Release 1.62]
  20
  21 * Fixed [@https://svn.boost.org/trac/boost/ticket/12179 Trac #12179].
  22
  23
  24 [heading Boost Release 1.61]
  25
  26 * Now `boost::optional` is specialized for reference parameters. This addresses a couple of issues:
  27   * the `sizeof` of optional reference is that of a pointer,
  28   * some bugs connected to copying optional references are gone,
  29   * all run-time bugs caused by incorrect reference binding on some compilers are now turned into compile-time errors,
  30   * you can swap optional references: it is like swapping pointers: shalow, underlying objects are not affected,
  31   * optional references to abstract types work.
  32 * Documented nested typedefs ([@https://svn.boost.org/trac/boost/ticket/5193 Trac #5193]).
  33 * 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>`.
  34 * Fixed [@https://svn.boost.org/trac/boost/ticket/10445 Trac #10445].
  35
  36
  37 [heading Boost Release 1.60]
  38
  39 * 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].
  40
  41
  42 [heading Boost Release 1.59]
  43
  44 * For C++03 compilers, added 0-argument overload for member function `emplace()`, and therewith removed the dependency on `<boost/utility/in_place_factory.hpp>`.
  45 * Fixed [@https://svn.boost.org/trac/boost/ticket/11241 Trac #11241].
  46
  47 [heading Boost Release 1.58]
  48
  49 * `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.
  50 * 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].
  51 * IOStream operators are now mentioned in documentation.
  52 * 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].
  53 * 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]).
  54 * Value accessors now work correctly on rvalues of `optional<T&>` ([@https://svn.boost.org/trac/boost/ticket/10839 Trac #10839]).
  55
  56
  57 [heading Boost Release 1.57]
  58
  59 * [@https://github.com/boostorg/optional/pull/9 Git pull #9]: ['"Supply `<string>` to fix C++03 compile error on `logic_error("...")`"].
  60
  61
  62 [heading Boost Release 1.56]
  63
  64 * Added support for rvalue references. Now `optional<T>` works with moveable but non-copyable `T`'s,
  65 * Improved `swap` (now uses move operations),
  66 * Added function `emplace()`. This is the last of the requests from [@https://svn.boost.org/trac/boost/ticket/1841 Trac #1841],
  67 * `optional` is moveable, including conditional `noexcept` specifications, which make it `move_if_noexcept`-friendly,
  68 * Using explicit operator bool() on platforms that support it ([@https://svn.boost.org/trac/boost/ticket/4227 Trac #4227]) (breaking change),
  69 * Forward declaration of `operator<<(ostream&, optional const&)` to prevent inadvertent incorrect serialization of optional objects,
  70 * Removed deprecated function `reset()` from examples ([@https://svn.boost.org/trac/boost/ticket/9005 Trac #9005]),
  71 * Equality comparison with `boost::none` does not require that `T` be EqualityComparable,
  72 * Optional rvalue references are explicitly disallowed,
  73 * Binding temporaries to optional references is explicitly disallowed (breaking change),
  74 * More ways to access the contained value, functions `value()`, `value_or()`, `value_or_eval()`,
  75 * Updated and reorganized documentation, added tutorial and quick guide sections.
  76
  77
  78
  79 [endsect][/ relnotes]