relnotes: info about breaking change

But I do not know if they copile with QuickBook.

.github/workflows/ci.yml

@@ -21,7 +21,8 @@ jobs:
             buildtype: "boost"
             packages: ""
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++"
             sources: ""
             llvm_os: ""
@@ -33,7 +34,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-4.7"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-4.7"
             sources: ""
             llvm_os: ""
@@ -45,7 +47,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-4.8"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-4.8"
             sources: ""
             llvm_os: ""
@@ -57,7 +60,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-4.9"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-4.9"
             sources: ""
             llvm_os: ""
@@ -69,7 +73,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-5"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-5"
             sources: ""
             llvm_os: ""
@@ -81,7 +86,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-6"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-6"
             sources: ""
             llvm_os: ""
@@ -93,7 +99,8 @@ jobs:
             buildtype: "boost"
             packages: "g++-7"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "g++-7"
             sources: ""
             llvm_os: ""
@@ -105,7 +112,7 @@ jobs:
             buildtype: "boost"
             packages: ""
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-18.04"
             cxx: "clang++"
             sources: ""
             llvm_os: ""
@@ -117,7 +124,8 @@ jobs:
             buildtype: "boost"
             packages: "clang-3.5 libstdc++-4.9-dev"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "clang++-3.5"
             sources: ""
             llvm_os: "precise"
@@ -129,7 +137,8 @@ jobs:
             buildtype: "boost"
             packages: "clang-3.6"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "clang++-3.6"
             sources: ""
             llvm_os: "precise"
@@ -141,7 +150,8 @@ jobs:
             buildtype: "boost"
             packages: "clang-3.7"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "clang++-3.7"
             sources: ""
             llvm_os: "precise"
@@ -153,7 +163,8 @@ jobs:
             buildtype: "boost"
             packages: "clang-3.8 libstdc++-4.9-dev"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "clang++-3.8"
             sources: ""
             llvm_os: "precise"
@@ -165,7 +176,8 @@ jobs:
             buildtype: "boost"
             packages: "clang-3.9 libstdc++-4.9-dev"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
+            container: "ubuntu:16.04"
             cxx: "clang++-3.9"
             sources: ""
             llvm_os: "precise"
@@ -177,7 +189,7 @@ jobs:
             buildtype: "boost"
             packages: "clang-4.0"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
             container: "ubuntu:14.04"
             cxx: "clang++-4.0"
             sources: ""
@@ -190,7 +202,7 @@ jobs:
             buildtype: "boost"
             packages: "clang-5.0"
             packages_to_remove: ""
-            os: "ubuntu-16.04"
+            os: "ubuntu-20.04"
             container: "ubuntu:14.04"
             cxx: "clang++-5.0"
             sources: ""
@@ -210,10 +222,12 @@ jobs:
       - name: If running in container, upgrade packages
         if: matrix.container != ''
         run: |
-            sudo apt-get -o Acquire::Retries=3 update && DEBIAN_FRONTEND=noninteractive apt-get -y install tzdata && apt-get -o Acquire::Retries=3 install -y sudo software-properties-common wget curl apt-transport-https make apt-file sudo unzip libssl-dev build-essential autotools-dev autoconf automake g++ libc++-helpers python python-pip ruby cpio gcc-multilib g++-multilib pkgconf python3 python3-pip ccache libpython-dev
+            apt-get -o Acquire::Retries=3 update && DEBIAN_FRONTEND=noninteractive apt-get -y install tzdata && apt-get -o Acquire::Retries=3 install -y sudo software-properties-common wget curl apt-transport-https make apt-file sudo unzip libssl-dev build-essential autotools-dev autoconf automake g++ libc++-helpers python ruby cpio gcc-multilib g++-multilib pkgconf python3 ccache libpython-dev
             sudo apt-add-repository ppa:git-core/ppa
             sudo apt-get -o Acquire::Retries=3 update && apt-get -o Acquire::Retries=3 -y install git
-            sudo python -m pip install --upgrade pip==20.3.4
+            python_version=$(python3 -c 'import sys; print("{0.major}.{0.minor}".format(sys.version_info))')
+            sudo wget https://bootstrap.pypa.io/pip/$python_version/get-pip.py
+            sudo python3 get-pip.py
             sudo /usr/local/bin/pip install cmake
 
       - uses: actions/checkout@v2

CMakeLists.txt

@@ -1,12 +1,9 @@
 # Copyright 2019 Mike Dev
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
-#
-# NOTE: CMake support for Boost.Optional is currently experimental at best
-#       and the interface is likely to change in the future
 
-cmake_minimum_required( VERSION 3.5 )
-project( BoostOptional )
+cmake_minimum_required( VERSION 3.5...3.20 )
+project( boost_optional VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX )
 
 add_library( boost_optional INTERFACE )
 add_library( Boost::optional ALIAS boost_optional )

doc/00_optional.qbk

@@ -2,7 +2,7 @@
     [quickbook 1.4]
     [authors [Cacciola Carballal, Fernando Luis]]
     [copyright 2003-2007 Fernando Luis Cacciola Carballal]
-    [copyright 2014-2020 Andrzej Krzemieński]
+    [copyright 2014-2022 Andrzej Krzemieński]
     [category miscellaneous]
     [id optional]
     [dirname optional]

doc/17_gotchas.qbk

@@ -61,12 +61,12 @@ When an optional object that contains a value is moved from (is a source of move
     assert (opi);
     assert (*opi == nullptr);
 
-Quite a lot of people expect that when an object that contains a value is moved from, its contained value should be destroyed. This is not so, for performance reasons. Current semantics allow the implementation of `boost::opiotnal<T>` to be trivially copyable when `T` is trivial.
+Quite a lot of people expect that when an object that contains a value is moved from, its contained value should be destroyed. This is not so, for performance reasons. Current semantics allow the implementation of `boost::optional<T>` to be trivially copyable when `T` is trivial.
 [endsect]
 
 [section Mixed relational comparisons]
 
-Because `T` is convertible to `optional<T>` and because `opiotnal<T>` is __SGI_LESS_THAN_COMPARABLE__ when `T` is __SGI_LESS_THAN_COMPARABLE__,
+Because `T` is convertible to `optional<T>` and because `optional<T>` is __SGI_LESS_THAN_COMPARABLE__ when `T` is __SGI_LESS_THAN_COMPARABLE__,
 you can sometimes get an unexpected runtime result where you would rather expect a compiler error:
 
     optional<double> Flight_plan::weight(); // sometimes no weight can be returned
@@ -108,4 +108,4 @@ This is obviously redundant, but makes the warning disappear.
 
 [endsect]
 
-[endsect]
+[endsect]

doc/23_ref_optional_io.qbk

@@ -26,11 +26,11 @@ template <class CharType, class CharTrait, class T>
   template <class CharType, class CharTrait>
   std::basic_ostream<CharType, CharTrait>&
   operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t const&); ``[link reference_operator_ostream_none __GO_TO__]``
-  
+
 template<class CharType, class CharTrait, class T>
   std::basic_istream<CharType, CharTrait>&
   operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v); ``[link reference_operator_istream __GO_TO__]``
-  
+
 } // namespace boost
 ```
 
@@ -43,8 +43,8 @@ template<class CharType, class CharTrait, class T>
 
 
 `template <class CharType, class CharTrait, class T>` [br]
-\u00A0\u00A0\u00A0\u00A0`std::basic_ostream<CharType, CharTrait>&` [br]
-\u00A0\u00A0\u00A0\u00A0`operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v);`
+ std::basic_ostream<CharType, CharTrait>&` [br]
+ operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v);`
 
 * [*Effect:] Outputs an implementation-defined string. The output contains the information about whether the optional object contains a value or not. If `v` contains a value, the output contains result of calling `out << *v`.
 * [*Returns:] `out`.
@@ -53,8 +53,8 @@ __SPACE__
 [#reference_operator_ostream_none]
 
 `template <class CharType, class CharTrait, class T>` [br]
-\u00A0\u00A0\u00A0\u00A0`std::basic_ostream<CharType, CharTrait>&` [br]
-\u00A0\u00A0\u00A0\u00A0`operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t);`
+ std::basic_ostream<CharType, CharTrait>&` [br]
+ operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t);`
 
 * [*Effect:] Outputs an implementation-defined string.
 * [*Returns:] `out`.
@@ -63,11 +63,11 @@ __SPACE__
 [#reference_operator_istream]
 
 `template <class CharType, class CharTrait, class T>` [br]
-\u00A0\u00A0\u00A0\u00A0`std::basic_ostream<CharType, CharTrait>&` [br]
-\u00A0\u00A0\u00A0\u00A0`operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v);`
+ std::basic_ostream<CharType, CharTrait>&` [br]
+ operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v);`
 
 * [*Requires:] `T` is __SGI_DEFAULT_CONSTRUCTIBLE__ and __MOVE_CONSTRUCTIBLE__.
-* [*Effect:] Reads the value of optional object from `in`. If the string representation indicates that the optional object should contain a value, `v` contains a value and its contained value is obtained as if by default-constructing an object `o` of type `T` and then calling `in >> o`; otherwise `v` does not contain a value, and the previously contained value (if any) has been destroyed. 
+* [*Effect:] Reads the value of optional object from `in`. If the string representation indicates that the optional object should contain a value, `v` contains a value and its contained value is obtained as if by default-constructing an object `o` of type `T` and then calling `in >> o`; otherwise `v` does not contain a value, and the previously contained value (if any) has been destroyed.
 * [*Returns:] `out`.
 
 [endsect]

doc/27_ref_optional_synopsis.qbk

@@ -73,6 +73,16 @@
 
     } // namespace boost
 
+    namespace std {
+
+    template <typename T>
+    struct hash<boost::optional<T> > ; ``[link reference_std_hash_spec __GO_TO__]``
+
+    template <typename T>
+    struct hash<boost::optional<T&> > ; ``[link reference_std_hash_spec __GO_TO__]``
+
+    } // namespace std
+
 
 [endsect]
 

doc/28_ref_optional_semantics.qbk

@@ -1408,3 +1408,37 @@ assert (addressof(*opt0) == addressof(y));
 ``
 
 [endsect]
+
+
+[section Detailed Semantics - std::hash Specializations]
+
+__SPACE__
+[#reference_std_hash_spec]
+
+``
+namespace std {
+
+template <typename T>
+struct hash<boost::optional<T> > ;
+
+template <typename T>
+struct hash<boost::optional<T&> > ;
+
+} // namespace std
+``
+
+The specialization `hash<optional<T>>` is enabled if and only if
+`hash<remove_­const_­t<T>>` is enabled. When enabled, for an object `o`
+of type `optional<T>`, if `o.has_­value() == true`, then `hash<optional<T>>()(o)`
+ evaluates to the same value as `hash<remove_­const_­t<T>>()(*o)`; otherwise it
+evaluates to an unspecified value.
+The member functions are not guaranteed to be `noexcept`.
+
+[caution
+You may get compiler errors when your program provides specializations for
+`std::hash<boost::optional<T>>`. If this happens, define macro
+`BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH` to suppress the specializations
+of `std::hash` in this library.
+]
+
+[endsect]

doc/91_relnotes.qbk

@@ -1,7 +1,7 @@
 [/
     Boost.Optional
 
-    Copyright (c) 2015 - 2018 Andrzej Krzemienski
+    Copyright (c) 2015 - 2022 Andrzej Krzemienski
 
     Distributed under the Boost Software License, Version 1.0.
     (See accompanying file LICENSE_1_0.txt or copy at
@@ -11,6 +11,18 @@
 
 [section:relnotes Release Notes]
 
+[heading Boost Release 1.80]
+
+* [*Breaking change:] Added specializations for `std::hash<boost::opitonal<T>>`. This fixes [@https://github.com/boostorg/optional/issues/55 issue #55]. You may get compiler errors when your program provides specializations for `std::hash<boost::optional<T>>`. If this happens, define macro `BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH` to suppress the specializations of `std::hash` in this library.
+
+[heading Boost Release 1.79]
+
+* Fixed [@https://github.com/boostorg/optional/issues/98 issue #98].
+
+[heading Boost Release 1.77]
+
+* Fixed [@https://github.com/boostorg/optional/issues/92 issue #92].
+
 [heading Boost Release 1.76]
 
 * Fixed MSVC warning C4702.

doc/html/boost_optional/acknowledgements.html

@@ -116,7 +116,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/dependencies_and_portability.html

@@ -77,7 +77,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/dependencies_and_portability/emplace_operations_in_older_compilers.html

@@ -76,7 +76,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/dependencies_and_portability/optional_reference_binding.html

@@ -93,7 +93,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/quick_start.html

@@ -155,7 +155,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/quick_start/bypassing_unnecessary_default_construction.html

@@ -61,7 +61,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/quick_start/optional_automatic_variables.html

@@ -61,7 +61,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/quick_start/optional_data_members.html

@@ -80,7 +80,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/quick_start/storage_in_containers.html

@@ -50,7 +50,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/reference/header__boost_optional_bad_optional_access_hpp_.html

@@ -49,7 +49,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/reference/header__boost_optional_bad_optional_access_hpp_/detailed_semantics.html

@@ -46,7 +46,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/reference/header__boost_optional_hpp_.html

@@ -33,7 +33,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/reference/header__boost_optional_optional_fwd_hpp_.html

@@ -52,7 +52,7 @@
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 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html

@@ -507,7 +507,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___optional_references.html

@@ -538,7 +538,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___optional_values.html

@@ -1774,7 +1774,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_in_place_init.html

@@ -47,7 +47,7 @@
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 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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       </p>

doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_optional_refs.html

@@ -104,7 +104,7 @@
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 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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       </p>

doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_optional_values.html

@@ -139,7 +139,7 @@
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 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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       </p>

doc/html/boost_optional/reference/io_header.html

@@ -58,7 +58,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/reference/io_header/io_semantics.html

@@ -98,7 +98,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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       </p>

doc/html/boost_optional/relnotes.html

@@ -28,6 +28,24 @@
 </h2></div></div></div>
 <h4>
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+      Release 1.79</a>
+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
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+<h4>
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+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
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+<h4>
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@@ -35,7 +53,7 @@
           Fixed MSVC warning C4702.
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 <h4>
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@@ -49,7 +67,7 @@
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@@ -72,7 +90,7 @@
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@@ -90,7 +108,7 @@
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@@ -107,7 +125,7 @@
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@@ -121,7 +139,7 @@
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@@ -139,7 +157,7 @@
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@@ -163,7 +181,7 @@
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@@ -171,7 +189,7 @@
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@@ -214,7 +232,7 @@
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@@ -225,7 +243,7 @@
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@@ -239,7 +257,7 @@
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@@ -275,7 +293,7 @@
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@@ -285,7 +303,7 @@
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 <h4>
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/design_overview.html

@@ -170,7 +170,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/design_overview/the_interface.html

@@ -173,7 +173,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/design_overview/the_semantics.html

@@ -107,7 +107,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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@@ -161,7 +161,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/tutorial/gotchas.html

@@ -98,7 +98,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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       </p>

doc/html/boost_optional/tutorial/gotchas/false_positive_with__wmaybe_uninitialized.html

@@ -63,7 +63,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
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doc/html/boost_optional/tutorial/gotchas/mixed_relational_comparisons.html

@@ -45,7 +45,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/gotchas/moved_from__optional_.html

@@ -49,7 +49,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/in_place_factories.html

@@ -183,7 +183,7 @@
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-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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doc/html/boost_optional/tutorial/io_operators.html

@@ -73,7 +73,7 @@
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+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
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       </p>

doc/html/boost_optional/tutorial/optional_references.html

@@ -103,7 +103,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/tutorial/optional_references/rebinding_semantics_for_assignment_of_optional_references.html

@@ -133,7 +133,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/tutorial/performance_considerations.html

@@ -251,7 +251,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/tutorial/relational_operators.html

@@ -99,7 +99,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/tutorial/type_requirements.html

@@ -95,7 +95,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/boost_optional/tutorial/when_to_use_optional.html

@@ -128,7 +128,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/index.html

@@ -26,7 +26,7 @@
 <span class="firstname">Fernando Luis</span> <span class="surname">Cacciola Carballal</span>
 </h3></div></div>
 <div><p class="copyright">Copyright © 2003-2007 Fernando Luis Cacciola Carballal</p></div>
-<div><p class="copyright">Copyright © 2014-2020 Andrzej Krzemieński</p></div>
+<div><p class="copyright">Copyright © 2014-2021 Andrzej Krzemieński</p></div>
 <div><div class="legalnotice">
 <a name="optional.legal"></a><p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
@@ -145,7 +145,7 @@
 </div>
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
-<td align="left"><p><small>Last revised: December 18, 2020 at 22:54:39 GMT</small></p></td>
+<td align="left"><p><small>Last revised: November 20, 2021 at 00:57:52 GMT</small></p></td>
 <td align="right"><div class="copyright-footer"></div></td>
 </tr></table>
 <hr>

doc/html/optional/reference.html

@@ -75,7 +75,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/optional/reference/header__boost_optional_optional_hpp_.html

@@ -97,7 +97,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

doc/html/optional/tutorial.html

@@ -139,7 +139,7 @@
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"></td>
-<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2020 Andrzej Krzemieński<p>
+<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2021 Andrzej Krzemieński<p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>

include/boost/optional/detail/optional_aligned_storage.hpp

@@ -28,7 +28,7 @@ class aligned_storage
     // BOOST_MAY_ALIAS works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
     union BOOST_MAY_ALIAS dummy_u
     {
-        char data[ sizeof(T) ];
+        unsigned char data[ sizeof(T) ];
         BOOST_DEDUCED_TYPENAME type_with_alignment<
           ::boost::alignment_of<T>::value >::type aligner_;
     } dummy_ ;

include/boost/optional/detail/optional_hash.hpp

@@ -0,0 +1,49 @@
+// Copyright (C) 2022 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/libs/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#ifndef BOOST_OPTIONAL_DETAIL_OPTIONAL_HASH_AJK_20MAY2022_HPP
+#define BOOST_OPTIONAL_DETAIL_OPTIONAL_HASH_AJK_20MAY2022_HPP
+
+#include <boost/optional/optional_fwd.hpp>
+#include <boost/config.hpp>
+
+#if !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
+
+#include <functional>
+
+namespace std
+{
+  template <typename T>
+  struct hash<boost::optional<T> >
+  {
+    typedef std::size_t result_type;
+    typedef boost::optional<T> argument_type;
+
+    BOOST_CONSTEXPR result_type operator()(const argument_type& arg) const {
+      return arg ? std::hash<T>()(*arg) : result_type();
+    }
+  };
+
+  template <typename T>
+  struct hash<boost::optional<T&> >
+  {
+    typedef std::size_t result_type;
+    typedef boost::optional<T&> argument_type;
+
+    BOOST_CONSTEXPR result_type operator()(const argument_type& arg) const {
+      return arg ? std::hash<T>()(*arg) : result_type();
+    }
+  };
+}
+
+#endif // !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
+
+#endif // header guard

include/boost/optional/detail/optional_trivially_copyable_base.hpp

@@ -1,3 +1,14 @@
+// Copyright (C) 2017 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/libs/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
 // trivilally-copyable version of the storage
 
 template<class T>
@@ -69,7 +80,7 @@ class tc_optional_base : public optional_tag
     // ~tc_optional_base() = default;
 
     // Assigns from another optional<T> (deep-copies the rhs value)
-    void assign ( tc_optional_base const& rhs ) 
+    void assign ( tc_optional_base const& rhs )
     {
       *this = rhs;
     }
@@ -84,7 +95,7 @@ class tc_optional_base : public optional_tag
 #else
         m_storage = static_cast<value_type>(rhs.get());
 #endif
-          
+
       m_initialized = rhs.is_initialized();
     }
 
@@ -99,7 +110,7 @@ class tc_optional_base : public optional_tag
       m_initialized = rhs.is_initialized();
     }
 #endif
-    
+
     void assign ( argument_type val )
     {
       construct(val);
@@ -166,7 +177,7 @@ class tc_optional_base : public optional_tag
     {
       construct(in_place_init, boost::forward<Args>(args)...);
     }
-     
+
     template<class... Args>
     explicit tc_optional_base ( in_place_init_t, Args&&... args )
       :
@@ -174,7 +185,7 @@ class tc_optional_base : public optional_tag
     {
       construct(in_place_init, boost::forward<Args>(args)...);
     }
-    
+
     template<class... Args>
     explicit tc_optional_base ( in_place_init_if_t, bool cond, Args&&... args )
       :
@@ -190,24 +201,24 @@ class tc_optional_base : public optional_tag
        m_storage = value_type( boost::forward<Arg>(arg) );
        m_initialized = true ;
      }
-     
+
     void construct ( in_place_init_t )
      {
        m_storage = value_type();
        m_initialized = true ;
      }
-     
+
     template<class Arg>
     void emplace_assign ( Arg&& arg )
      {
        construct(in_place_init, boost::forward<Arg>(arg)) ;
      }
-     
+
     void emplace_assign ()
      {
        construct(in_place_init) ;
      }
-     
+
     template<class Arg>
     explicit tc_optional_base ( in_place_init_t, Arg&& arg )
       :
@@ -215,11 +226,11 @@ class tc_optional_base : public optional_tag
     {
       construct(in_place_init, boost::forward<Arg>(arg));
     }
-    
+
     explicit tc_optional_base ( in_place_init_t )
       :
       m_initialized(false), m_storage() {}
-    
+
     template<class Arg>
     explicit tc_optional_base ( in_place_init_if_t, bool cond, Arg&& arg )
       :
@@ -228,7 +239,7 @@ class tc_optional_base : public optional_tag
       if ( cond )
         construct(in_place_init, boost::forward<Arg>(arg));
     }
-    
+
     explicit tc_optional_base ( in_place_init_if_t, bool cond )
       :
       m_initialized(false)
@@ -238,21 +249,21 @@ class tc_optional_base : public optional_tag
     }
 
 #else
-     
+
     template<class Arg>
     void construct ( in_place_init_t, const Arg& arg )
      {
        m_storage = value_type( arg );
        m_initialized = true ;
      }
-     
+
     template<class Arg>
     void construct ( in_place_init_t, Arg& arg )
      {
        m_storage = value_type( arg );
        m_initialized = true ;
      }
-     
+
     void construct ( in_place_init_t )
      {
        m_storage = value_type();
@@ -264,18 +275,18 @@ class tc_optional_base : public optional_tag
     {
       construct(in_place_init, arg);
     }
-     
+
     template<class Arg>
     void emplace_assign ( Arg& arg )
     {
       construct(in_place_init, arg);
     }
-     
+
     void emplace_assign ()
     {
       construct(in_place_init);
     }
-    
+
     template<class Arg>
     explicit tc_optional_base ( in_place_init_t, const Arg& arg )
       : m_initialized(false)
@@ -289,13 +300,13 @@ class tc_optional_base : public optional_tag
     {
       construct(in_place_init, arg);
     }
-    
+
     explicit tc_optional_base ( in_place_init_t )
       : m_initialized(false)
     {
       construct(in_place_init);
     }
-    
+
     template<class Arg>
     explicit tc_optional_base ( in_place_init_if_t, bool cond, const Arg& arg )
       : m_initialized(false)
@@ -303,15 +314,15 @@ class tc_optional_base : public optional_tag
       if ( cond )
         construct(in_place_init, arg);
     }
-    
+
     template<class Arg>
     explicit tc_optional_base ( in_place_init_if_t, bool cond, Arg& arg )
       : m_initialized(false)
     {
       if ( cond )
         construct(in_place_init, arg);
-    } 
-    
+    }
+
     explicit tc_optional_base ( in_place_init_if_t, bool cond )
       : m_initialized(false)
     {

include/boost/optional/optional.hpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
-// Copyright (C) 2014 - 2018 Andrzej Krzemienski.
+// Copyright (C) 2014 - 2021 Andrzej Krzemienski.
 //
 // Use, modification, and distribution is subject to the Boost Software
 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
@@ -18,7 +18,9 @@
 #define BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP
 
 #include <new>
+#ifndef BOOST_NO_IOSTREAM
 #include <iosfwd>
+#endif // BOOST_NO_IOSTREAM
 
 #ifdef BOOST_OPTIONAL_DETAIL_USE_STD_TYPE_TRAITS
 #  include <type_traits>
@@ -35,14 +37,18 @@
 #include <boost/type.hpp>
 #include <boost/type_traits/alignment_of.hpp>
 #include <boost/type_traits/conditional.hpp>
+#include <boost/type_traits/conjunction.hpp>
+#include <boost/type_traits/disjunction.hpp>
 #include <boost/type_traits/has_nothrow_constructor.hpp>
 #include <boost/type_traits/type_with_alignment.hpp>
 #include <boost/type_traits/remove_const.hpp>
 #include <boost/type_traits/remove_reference.hpp>
 #include <boost/type_traits/decay.hpp>
+#include <boost/type_traits/is_assignable.hpp>
 #include <boost/type_traits/is_base_of.hpp>
 #include <boost/type_traits/is_const.hpp>
 #include <boost/type_traits/is_constructible.hpp>
+#include <boost/type_traits/is_convertible.hpp>
 #include <boost/type_traits/is_lvalue_reference.hpp>
 #include <boost/type_traits/is_nothrow_move_assignable.hpp>
 #include <boost/type_traits/is_nothrow_move_constructible.hpp>
@@ -59,6 +65,7 @@
 #include <boost/optional/detail/optional_config.hpp>
 #include <boost/optional/detail/optional_factory_support.hpp>
 #include <boost/optional/detail/optional_aligned_storage.hpp>
+#include <boost/optional/detail/optional_hash.hpp>
 
 namespace boost { namespace optional_detail {
 
@@ -123,6 +130,7 @@ class optional_base : public optional_tag
   protected :
 
     typedef T value_type ;
+    typedef typename boost::remove_const<T>::type unqualified_value_type;
 
   protected:
     typedef T &       reference_type ;
@@ -399,14 +407,14 @@ class optional_base : public optional_tag
 
     void construct ( argument_type val )
      {
-       ::new (m_storage.address()) value_type(val) ;
+       ::new (m_storage.address()) unqualified_value_type(val) ;
        m_initialized = true ;
      }
 
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
     void construct ( rval_reference_type val )
      {
-       ::new (m_storage.address()) value_type( boost::move(val) ) ;
+       ::new (m_storage.address()) unqualified_value_type( boost::move(val) ) ;
        m_initialized = true ;
      }
 #endif
@@ -418,7 +426,7 @@ class optional_base : public optional_tag
     template<class... Args>
     void construct ( in_place_init_t, Args&&... args )
     {
-      ::new (m_storage.address()) value_type( boost::forward<Args>(args)... ) ;
+      ::new (m_storage.address()) unqualified_value_type( boost::forward<Args>(args)... ) ;
       m_initialized = true ;
     }
 
@@ -449,13 +457,13 @@ class optional_base : public optional_tag
     template<class Arg>
     void construct ( in_place_init_t, Arg&& arg )
      {
-       ::new (m_storage.address()) value_type( boost::forward<Arg>(arg) );
+       ::new (m_storage.address()) unqualified_value_type( boost::forward<Arg>(arg) );
        m_initialized = true ;
      }
 
     void construct ( in_place_init_t )
      {
-       ::new (m_storage.address()) value_type();
+       ::new (m_storage.address()) unqualified_value_type();
        m_initialized = true ;
      }
 
@@ -509,20 +517,20 @@ class optional_base : public optional_tag
     template<class Arg>
     void construct ( in_place_init_t, const Arg& arg )
      {
-       ::new (m_storage.address()) value_type( arg );
+       ::new (m_storage.address()) unqualified_value_type( arg );
        m_initialized = true ;
      }
 
     template<class Arg>
     void construct ( in_place_init_t, Arg& arg )
      {
-       ::new (m_storage.address()) value_type( arg );
+       ::new (m_storage.address()) unqualified_value_type( arg );
        m_initialized = true ;
      }
 
     void construct ( in_place_init_t )
      {
-       ::new (m_storage.address()) value_type();
+       ::new (m_storage.address()) unqualified_value_type();
        m_initialized = true ;
      }
 
@@ -667,7 +675,7 @@ class optional_base : public optional_tag
     template<class Expr>
     void construct ( Expr&& expr, void const* )
     {
-      new (m_storage.address()) value_type(boost::forward<Expr>(expr)) ;
+      new (m_storage.address()) unqualified_value_type(boost::forward<Expr>(expr)) ;
       m_initialized = true ;
     }
 
@@ -688,7 +696,7 @@ class optional_base : public optional_tag
     template<class Expr>
     void construct ( Expr const& expr, void const* )
      {
-       new (m_storage.address()) value_type(expr) ;
+       new (m_storage.address()) unqualified_value_type(expr) ;
        m_initialized = true ;
      }
 
@@ -726,7 +734,7 @@ class optional_base : public optional_tag
        {
          // An exception can be thrown here.
          // It it happens, THIS will be left uninitialized.
-         new (m_storage.address()) value_type(boost::move(expr.get())) ;
+         new (m_storage.address()) unqualified_value_type(boost::move(expr.get())) ;
          m_initialized = true ;
        }
      }
@@ -739,7 +747,7 @@ class optional_base : public optional_tag
        {
          // An exception can be thrown here.
          // It it happens, THIS will be left uninitialized.
-         new (m_storage.address()) value_type(expr.get()) ;
+         new (m_storage.address()) unqualified_value_type(expr.get()) ;
          m_initialized = true ;
        }
      }
@@ -779,7 +787,7 @@ class optional_base : public optional_tag
 
 // definition of metafunction is_optional_val_init_candidate
 template <typename U>
-struct is_optional_related
+struct is_optional_or_tag
   : boost::conditional< boost::is_base_of<optional_detail::optional_tag, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value
                      || boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<U>::type, none_t>::value
                      || boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<U>::type, in_place_init_t>::value
@@ -787,14 +795,22 @@ struct is_optional_related
     boost::true_type, boost::false_type>::type
 {};
 
+template <typename T, typename U>
+struct has_dedicated_constructor
+  : boost::disjunction<is_optional_or_tag<U>, boost::is_same<T, BOOST_DEDUCED_TYPENAME boost::decay<U>::type> >
+{};
+
+template <typename U>
+struct is_in_place_factory
+  : boost::disjunction< boost::is_base_of<boost::in_place_factory_base, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>,
+                        boost::is_base_of<boost::typed_in_place_factory_base, BOOST_DEDUCED_TYPENAME boost::decay<U>::type> >
+{};
+
 #if !defined(BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT)
 
 template <typename T, typename U>
-struct is_convertible_to_T_or_factory
-  : boost::conditional< boost::is_base_of<boost::in_place_factory_base, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value
-                     || boost::is_base_of<boost::typed_in_place_factory_base, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value
-                     || (boost::is_constructible<T, U&&>::value && !boost::is_same<T, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value)
-                      , boost::true_type, boost::false_type>::type
+struct is_factory_or_constructible_to_T
+  : boost::disjunction< is_in_place_factory<U>, boost::is_constructible<T, U&&> >
 {};
 
 template <typename T, typename U>
@@ -804,7 +820,7 @@ struct is_optional_constructible : boost::is_constructible<T, U>
 #else
 
 template <typename, typename>
-struct is_convertible_to_T_or_factory : boost::true_type
+struct is_factory_or_constructible_to_T : boost::true_type
 {};
 
 template <typename T, typename U>
@@ -813,15 +829,58 @@ struct is_optional_constructible : boost::true_type
 
 #endif // is_convertible condition
 
-template <typename T, typename U, bool = is_optional_related<U>::value>
+#if !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800)
+// for is_assignable
+
+#if (!defined BOOST_NO_CXX11_RVALUE_REFERENCES)
+// On some initial rvalue reference implementations GCC does it in a strange way,
+// preferring perfect-forwarding constructor to implicit copy constructor.
+
+template <typename T, typename U>
+struct is_opt_assignable
+  : boost::conjunction<boost::is_convertible<U&&, T>, boost::is_assignable<T&, U&&> >
+{};
+
+#else
+
+template <typename T, typename U>
+struct is_opt_assignable
+  : boost::conjunction<boost::is_convertible<U, T>, boost::is_assignable<T&, U> >
+{};
+
+#endif
+
+#else
+
+template <typename T, typename U>
+struct is_opt_assignable : boost::is_convertible<U, T>
+{};
+
+#endif
+
+template <typename T, typename U>
+struct is_factory_or_opt_assignable_to_T
+  : boost::disjunction< is_in_place_factory<U>, is_opt_assignable<T, U> >
+{};
+
+template <typename T, typename U, bool = has_dedicated_constructor<T, U>::value>
 struct is_optional_val_init_candidate
   : boost::false_type
 {};
 
 template <typename T, typename U>
 struct is_optional_val_init_candidate<T, U, false>
-  : boost::conditional< is_convertible_to_T_or_factory<T, U>::value
-                      , boost::true_type, boost::false_type>::type
+  : is_factory_or_constructible_to_T<T, U>
+{};
+
+template <typename T, typename U, bool = has_dedicated_constructor<T, U>::value>
+struct is_optional_val_assign_candidate
+  : boost::false_type
+{};
+
+template <typename T, typename U>
+struct is_optional_val_assign_candidate<T, U, false>
+  : is_factory_or_opt_assignable_to_T<T, U>
 {};
 
 } // namespace optional_detail
@@ -994,7 +1053,7 @@ class optional
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
 
     template<class Expr>
-    BOOST_DEDUCED_TYPENAME boost::enable_if<optional_detail::is_optional_val_init_candidate<T, Expr>, optional&>::type
+    BOOST_DEDUCED_TYPENAME boost::enable_if<optional_detail::is_optional_val_assign_candidate<T, Expr>, optional&>::type
     operator= ( Expr&& expr )
       {
         this->assign_expr(boost::forward<Expr>(expr),boost::addressof(expr));
@@ -1586,6 +1645,7 @@ get_pointer ( optional<T>& opt )
 
 } // namespace boost
 
+#ifndef BOOST_NO_IOSTREAM
 namespace boost {
 
 // The following declaration prevents a bug where operator safe-bool is used upon streaming optional object if you forget the IO header.
@@ -1598,6 +1658,7 @@ operator<<(std::basic_ostream<CharType, CharTrait>& os, optional_detail::optiona
 }
 
 } // namespace boost
+#endif // BOOST_NO_IOSTREAM
 
 #include <boost/optional/detail/optional_relops.hpp>
 #include <boost/optional/detail/optional_swap.hpp>

include/boost/optional/optional_io.hpp

@@ -12,6 +12,7 @@
 #ifndef BOOST_OPTIONAL_OPTIONAL_IO_FLC_19NOV2002_HPP
 #define BOOST_OPTIONAL_OPTIONAL_IO_FLC_19NOV2002_HPP
 
+#ifndef BOOST_NO_IOSTREAM
 #include <istream>
 #include <ostream>
 
@@ -31,7 +32,7 @@ operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t)
   {
     out << "--";
   }
-   
+
   return out;
 }
 
@@ -90,5 +91,5 @@ operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v)
 
 } // namespace boost
 
+#endif // BOOST_NO_IOSTREAM
 #endif
-

test/Jamfile.v2

@@ -22,9 +22,11 @@ import testing ;
     [ run optional_test_swap.cpp ]
     [ run optional_test_conversions_from_U.cpp ]
     [ run optional_test_convert_from_T.cpp ]
+    [ run optional_test_convert_assign.cpp ]
     [ run optional_test_empty_braces.cpp ]
     [ run optional_test_make_optional.cpp ]
     [ run optional_test_flat_map.cpp ]
+    [ run optional_test_hash.cpp ]
     [ run optional_test_map.cpp ]
     [ run optional_test_tie.cpp ]
     [ run optional_test_ref_assign_portable_minimum.cpp ]

test/optional_test.cpp

@@ -12,7 +12,9 @@
 // Revisions:
 // 12 May 2008 (added more swap tests)
 //
+#ifndef BOOST_NO_IOSTREAM
 #include<iostream>
+#endif // BOOST_NO_IOSTREAM
 #include<stdexcept>
 #include<string>
 
@@ -908,7 +910,7 @@ void test_no_implicit_conversions()
 
 
 // Test for support for classes with overridden operator&
-class CustomAddressOfClass  
+class CustomAddressOfClass
 {
     int n;
 
@@ -950,5 +952,3 @@ int main()
 
   return boost::report_errors();
 }
-
-

test/optional_test_convert_assign.cpp

@@ -0,0 +1,57 @@
+// Copyright (C) 2021 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#include "boost/core/lightweight_test.hpp"
+#include "boost/none.hpp"
+
+//#ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
+
+using boost::optional;
+
+struct implicit_bool_conv
+{
+  operator bool() const { return false; }
+};
+
+struct explicit_bool_conv
+{
+  bool operator!() const BOOST_NOEXCEPT { return false; }
+  BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
+};
+
+template <typename To, typename From>
+void test_convert_assign()
+{
+  optional<To> oi;
+  oi = From();
+  BOOST_TEST(oi);
+}
+
+void test_no_bad_assignment()
+{
+#if !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800)
+  // this means that type trait `boost::is_assignable` works.
+  BOOST_STATIC_ASSERT((boost::is_assignable<optional<bool>&, bool>::value));
+  BOOST_STATIC_ASSERT((boost::is_assignable<optional<bool>&, implicit_bool_conv>::value));
+  BOOST_STATIC_ASSERT((! boost::is_assignable<optional<bool>&, explicit_bool_conv>::value));
+#endif
+}
+
+int main()
+{
+  test_convert_assign<int, short>();
+  test_convert_assign<bool, implicit_bool_conv>();
+  test_no_bad_assignment();
+
+  return boost::report_errors();
+}

test/optional_test_hash.cpp

@@ -0,0 +1,64 @@
+// Copyright (C) 2014 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+#include "boost/config.hpp"
+#include "boost/core/lightweight_test.hpp"
+
+#if !defined(BOOST_NO_CXX11_HDR_UNORDERED_SET) && !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH)
+
+#include <unordered_set>
+
+void test_unordered_map()
+{
+  std::unordered_set<boost::optional<int> > set;
+  set.insert(boost::optional<int>(1));
+  set.insert(boost::optional<int>(1));
+
+
+  BOOST_TEST(set.size() == 1u);
+  BOOST_TEST(set.find(boost::optional<int>(1)) != set.end());
+}
+
+#else
+
+void test_unordered_map()
+{}
+
+#endif
+
+
+#if !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
+
+void tets_hash()
+{
+  std::hash<boost::optional<int> > hash_int;
+  boost::optional<int> oN;
+  boost::optional<int> o1(1);
+
+  BOOST_TEST(hash_int(oN) == hash_int(oN));
+  BOOST_TEST(hash_int(o1) == hash_int(o1));
+}
+
+#else
+
+void tets_hash()
+{}
+
+#endif
+
+
+int main()
+{
+  test_unordered_map();
+  tets_hash();
+  return boost::report_errors();
+}

test/optional_test_io.cpp

@@ -10,15 +10,19 @@
 // You are welcome to contact the author at:
 //  fernando_cacciola@hotmail.com
 
-#include <sstream>
 #include "boost/optional/optional.hpp"
 #include "boost/optional/optional_io.hpp"
+#include "boost/core/lightweight_test.hpp"
+
+#ifndef BOOST_NO_IOSTREAM
+
+#include <sstream>
 
 #ifdef BOOST_BORLANDC
 #pragma hdrstop
 #endif
 
-#include "boost/core/lightweight_test.hpp"
+
 
 using boost::optional;
 
@@ -29,7 +33,7 @@ void test2( Opt o, Opt buff )
 
   const int markv = 123 ;
   int mark = 0 ;
-  
+
   s << o << " " << markv ;
   s >> buff >> mark ;
 
@@ -85,3 +89,12 @@ int main()
 
   return boost::report_errors();
 }
+
+#else // BOOST_NO_IOSTREAM
+
+int main()
+{
+  return boost::report_errors();
+}
+
+#endif // BOOST_NO_IOSTREAM