Merge branch 'develop'

Fixed recurring typo

.travis.yml

@@ -0,0 +1,199 @@
+# Copyright 2016, 2017 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
+
+language: cpp
+
+sudo: false
+
+python: "2.7"
+
+branches:
+  only:
+    - master
+    - develop
+    - /feature\/.*/
+
+env:
+  matrix:
+    - BOGUS_JOB=true
+
+matrix:
+
+  exclude:
+    - env: BOGUS_JOB=true
+
+  include:
+    - os: linux
+      compiler: g++
+      env: TOOLSET=gcc COMPILER=g++ CXXSTD=03,11
+
+    - os: linux
+      compiler: g++-4.7
+      env: TOOLSET=gcc COMPILER=g++-4.7 CXXSTD=03,11
+      addons:
+        apt:
+          packages:
+            - g++-4.7
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: g++-4.8
+      env: TOOLSET=gcc COMPILER=g++-4.8 CXXSTD=03,11
+      addons:
+        apt:
+          packages:
+            - g++-4.8
+          sources:
+            - ubuntu-toolchain-r-test
+    - os: linux
+      compiler: g++-4.9
+      env: TOOLSET=gcc COMPILER=g++-4.9 CXXSTD=03,11
+      addons:
+        apt:
+          packages:
+            - g++-4.9
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: g++-5
+      env: TOOLSET=gcc COMPILER=g++-5 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - g++-5
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: g++-6
+      env: TOOLSET=gcc COMPILER=g++-6 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - g++-6
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      dist: trusty
+      compiler: g++-7
+      env: TOOLSET=gcc COMPILER=g++-7 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - g++-7
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: clang++
+      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11
+
+    - os: linux
+      compiler: clang++-3.5
+      env: TOOLSET=clang COMPILER=clang++-3.5 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-3.5
+            - libstdc++-4.9-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.5
+
+    - os: linux
+      compiler: clang++-3.6
+      env: TOOLSET=clang COMPILER=clang++-3.6 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-3.6
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.6
+
+    - os: linux
+      compiler: clang++-3.7
+      env: TOOLSET=clang COMPILER=clang++-3.7 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-3.7
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.7
+
+    - os: linux
+      compiler: clang++-3.8
+      env: TOOLSET=clang COMPILER=clang++-3.8 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-3.8
+            - libstdc++-4.9-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.8
+
+    - os: linux
+      compiler: clang++-3.9
+      env: TOOLSET=clang COMPILER=clang++-3.9 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-3.9
+            - libstdc++-4.9-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.9
+
+    - os: linux
+      compiler: clang++-4.0
+      env: TOOLSET=clang COMPILER=clang++-4.0 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-4.0
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-4.0
+
+    - os: linux
+      compiler: clang++-5.0
+      env: TOOLSET=clang COMPILER=clang++-5.0 CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - clang-5.0
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-5.0
+
+    - os: osx
+      compiler: clang++
+      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+
+install:
+  - BOOST_BRANCH=develop && [ "$TRAVIS_BRANCH" == "master" ] && BOOST_BRANCH=master || true
+  - cd ..
+  - git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
+  - cd boost-root
+  - git submodule update --init tools/build
+  - git submodule update --init libs/config
+  - git submodule update --init tools/boostdep
+  - cp -r $TRAVIS_BUILD_DIR/* libs/optional
+  - python tools/boostdep/depinst/depinst.py optional
+  - ./bootstrap.sh
+  - ./b2 headers
+
+script:
+  - |-
+    echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
+  - ./b2 libs/optional/test toolset=$TOOLSET cxxstd=$CXXSTD
+
+notifications:
+  email:
+    on_success: always

doc/00_optional.qbk

@@ -2,7 +2,7 @@
     [quickbook 1.4]
     [authors [Cacciola Carballal, Fernando Luis]]
     [copyright 2003-2007 Fernando Luis Cacciola Carballal]
-    [copyright 2014-2016 Andrzej Krzemieński]
+    [copyright 2014-2017 Andrzej Krzemieński]
     [category miscellaneous]
     [id optional]
     [dirname optional]

doc/17_gotchas.qbk

@@ -102,7 +102,7 @@ Sometimes on GCC compilers below version 5.1 you may get an -Wmaybe-uninitialize
     
 This is a bug in the compiler. As a workaround (provided in [@http://stackoverflow.com/questions/21755206/how-to-get-around-gcc-void-b-4-may-be-used-uninitialized-in-this-funct this Stack Overflow question]) use the following way of initializing an optional containing no value:
 
-    boost::optional<int> b = std::make_optional(false, int());
+    boost::optional<int> b = boost::make_optional(false, int());
 
 This is obviously redundant, but makes the warning disappear.
 

doc/1A_on_performance.qbk

@@ -1,7 +1,7 @@
 
 [section Performance considerations]
 
-Technical details aside, the memory layout of `optional<T>` is more-less this:
+Technical details aside, the memory layout of `optional<T>` for a generic `T` is more-less this:
 
   template <typename T>
   class optional
@@ -9,8 +9,33 @@ Technical details aside, the memory layout of `optional<T>` is more-less this:
     bool _initialized;
     std::aligned_storage_t<sizeof(t), alignof(T)> _storage;
   };
+
+Lifetime of the `T` inside `_storage` is manually controlled with placement-`new`s and pseudo-destructor calls. However, for scalar `T`s we use a different way of storage, by simply holding a `T`:
   
-But for the purpose of this analysis, considering memory layouts, we can think of it as:
+  template <typename T>
+  class optional
+  {
+    bool _initialized;
+    T _storage;
+  };
+
+We call it a ['direct] storage. This makes `optional<T>` a trivially-copyable type for scalar `T`s. This only works for compilers that support defaulted functions (including defaulted move assignment and constructor). On compilers without defaulted functions we still use the direct storage, but `optional<T>` is no longer recognized as trivially-copyable. Apart from scalar types, we leave the programmer a way of customizing her type, so that it is reconized by `optional` as candidate for optimized storage, by specializing type trait `boost::opitonal_config::optional_uses_direct_storage_for`:
+
+  struct X // not trivial
+  {
+    X() {}
+  };
+
+  namespace boost { namespace optional_config {
+    
+    template <> struct optional_uses_direct_storage_for<X> : boost::true_type {};
+    
+  }}
+  
+
+[heading Controlling the size]
+  
+For the purpose of the following analysis, considering memory layouts, we can think of it as:
 
   template <typename T>
   class optional

doc/27_ref_optional_synopsis.qbk

@@ -15,6 +15,12 @@
 
     namespace boost {
 
+    class in_place_init_t { /* see below */ } ; ``[link reference_in_place_init __GO_TO__]``
+    const in_place_init_t in_place_init ( /* see below */ ) ;
+    
+    class in_place_init_if_t { /*see below*/ } ; ``[link reference_in_place_init_if __GO_TO__]``
+    const in_place_init_if_t in_place_init_if ( /*see below*/ ) ;
+    
     template <class T>
     class optional ; ``[link reference_operator_template __GO_TO__]``
     
@@ -38,8 +44,12 @@
     template<class T> inline bool operator != ( optional<T> const& x, none_t ) noexcept ; ``[link reference_operator_compare_not_equal_optional_none __GO_TO__]``
 
     template<class T> inline optional<T> make_optional ( T const& v ) ; ``[link reference_make_optional_value __GO_TO__]``
+    
+    template<class T> inline optional<std::decay_t<T>> make_optional ( T && v ) ; ``[link reference_make_optional_rvalue __GO_TO__]``
 
     template<class T> inline optional<T> make_optional ( bool condition, T const& v ) ; ``[link reference_make_optional_bool_value __GO_TO__]``
+    
+    template<class T> inline optional<std::decay_t<T>> make_optional ( bool condition, T && v ) ; ``[link reference_make_optional_bool_rvalue __GO_TO__]``
 
     template<class T> inline auto get_optional_value_or ( optional<T> const& opt, typename optional<T>::reference_const_type def ) -> typename optional<T>::reference_const_type; ``[link reference_free_get_value_or __GO_TO__]`` 
     
@@ -67,6 +77,26 @@
 [endsect]
 
 
+[section:header_optional_in_place_init Initialization tags]
+
+[#reference_in_place_init]
+[#reference_in_place_init_if]
+
+    namespace boost {
+
+    class in_place_init_t { /* see below */ } ;
+    const in_place_init_t in_place_init ( /* see below */ ) ;
+    
+    class in_place_init_if_t { /*see below*/ } ;
+    const in_place_init_if_t in_place_init_if ( /*see below*/ ) ;
+    
+    }
+
+Classes `in_place_init_t` and `in_place_init_if_t` are empty clsses. Their purpose is to control overload resolution in the initialization of optional objects. 
+They are empty, trivially copyable classes with disabled default constructor.  
+
+[endsect]
+
 [section:header_optional_optional_values Optional Values]
 
 [#reference_operator_template]
@@ -91,7 +121,6 @@
         
         optional ( T&& v ) ; ``[link reference_optional_constructor_move_value __GO_TO__]``
 
-        // [new in 1.34]
         optional ( bool condition, T const& v ) ; ``[link reference_optional_constructor_bool_value __GO_TO__]`` 
 
         optional ( optional const& rhs ) ; ``[link reference_optional_constructor_optional __GO_TO__]``
@@ -101,6 +130,10 @@
         template<class U> explicit optional ( optional<U> const& rhs ) ; ``[link reference_optional_constructor_other_optional __GO_TO__]``
         
         template<class U> explicit optional ( optional<U>&& rhs ) ; ``[link reference_optional_move_constructor_other_optional __GO_TO__]``
+        
+        template<class... Args> explicit optional ( in_place_init_t, Args&&... args ) ; ``[link reference_optional_in_place_init __GO_TO__]``
+        
+        template<class... Args> explicit optional ( in_place_init_if_t, bool condition, Args&&... args ) ; ``[link reference_optional_in_place_init_if __GO_TO__]``
 
         template<class InPlaceFactory> explicit optional ( InPlaceFactory const& f ) ; ``[link reference_optional_constructor_factory __GO_TO__]``
 

doc/28_ref_optional_semantics.qbk

@@ -224,6 +224,53 @@ assert( *y == 123 ) ;
 
 __SPACE__
 
+[#reference_optional_in_place_init]
+
+[: `template<class... Args> explicit optional<T>::optional( in_place_init_t, Args&&... ars );`]
+
+* [*Requires:] `is_constructible_v<T, Args&&...>` is `true`.
+* [*Effect:] Initializes the contained value as if direct-non-list-initializing an object of type `T` with the
+arguments `std::forward<Args>(args)...`.
+* [*Postconditions:] `*this` is initialized.
+* [*Throws:] Any exception thrown by the selected constructor of `T`.
+* [*Notes: ] `T` need not be __MOVE_CONSTRUCTIBLE__. On compilers that do not suppor variadic templates or rvalue references, this constuctor is available in limited functionality. For details [link optional_emplace_workaround see here]. 
+
+* [*Example:]
+``
+// creates an std::mutex using its default constructor
+optional<std::mutex> om {in_place_init};
+assert (om);
+
+// creates a unique_lock by calling unique_lock(*om, std::defer_lock)
+optional<std::unique_lock<std::mutex>> ol {in_place_init, *om, std::defer_lock};
+assert (ol);
+assert (!ol->owns_lock());
+``
+
+__SPACE__
+
+[#reference_optional_in_place_init_if]
+
+[: `template<class... Args> explicit optional<T>::optional( in_place_init_if_t, bool condition, Args&&... ars );`]
+
+* [*Requires:] `is_constructible_v<T, Args&&...>` is `true`.
+* [*Effect:] If `condition` is `true`, initializes the contained value as if direct-non-list-initializing an object of type `T` with the arguments `std::forward<Args>(args)...`.
+* [*Postconditions:] `bool(*this) == condition`.
+* [*Throws:] Any exception thrown by the selected constructor of `T`.
+* [*Notes: ] `T` need not be __MOVE_CONSTRUCTIBLE__. On compilers that do not suppor variadic templates or rvalue references, this constuctor is available in limited functionality. For details [link optional_emplace_workaround see here]. 
+
+* [*Example:]
+``
+optional<std::vector<std::string>> ov1 {in_place_init_if, false, 3, "A"};
+assert (!ov1);
+
+optional<std::vector<std::string>> ov2 {in_place_init_if, true, 3, "A"};
+assert (ov2);
+assert (ov2->size() == 3);
+``
+
+__SPACE__
+
 [#reference_optional_constructor_factory]
 
 [: `template<InPlaceFactory> explicit optional<T>::optional( InPlaceFactory const& f );`]
@@ -455,9 +502,7 @@ __SPACE__
 * [*Postconditions: ] `*this` is [_initialized].
 * [*Throws:] Whatever the selected `T`'s  constructor throws.
 * [*Exception Safety:] If an exception is thrown during the initialization of `T`, `*this` is ['uninitialized].
-* [*Notes:] `T` need not be __MOVE_CONSTRUCTIBLE__ or `MoveAssignable`. 
- On compilers that do not support variadic templates, the signature falls back to two overloads:`template<class Arg> void emplace(Arg&& arg)` and `void emplace()`. 
- On compilers that do not support rvalue references, the signature falls back to three overloads: taking `const` and non-`const` lvalue reference, and third with empty function argument list. 
+* [*Notes:] `T` need not be __MOVE_CONSTRUCTIBLE__ or `MoveAssignable`. On compilers that do not suppor variadic templates or rvalue references, this function is available in limited functionality. For details [link optional_emplace_workaround see here].  
 * [*Example:]
 ``
 T v;
@@ -1052,6 +1097,15 @@ template<class T> void foo ( optional<T> const& opt ) ;
 foo ( make_optional(1+1) ) ; // Creates an optional<int>
 ``
 
+__SPACE__
+
+[#reference_make_optional_rvalue]
+
+[: `optional<std::decay_t<T>> make_optional( T && v )`]
+
+* [*Returns: ] `optional<std::decay_t<T>>(std::move(v))` for the ['deduced] type `T` of `v`.
+
+
 __SPACE__
 
 [#reference_make_optional_bool_value]
@@ -1072,6 +1126,15 @@ if ( !v )
   error("foo wasn't computed");
 ``
 
+__SPACE__
+
+[#reference_make_optional_bool_rvalue]
+
+[: `optional<std::decay_t<T>> make_optional( bool condition, T && v )`]
+
+* [*Returns: ] `optional<std::decay_t<T>>(condition, std::move(v))` for the ['deduced] type `T` of `v`.
+
+
 __SPACE__
 
 [#reference_operator_compare_equal_optional_optional]

doc/90_dependencies.qbk

@@ -27,6 +27,41 @@ The implementation uses the following other Boost modules:
 
 [endsect]
 
+[section Emplace operations in older compilers][#optional_emplace_workaround]
+
+Certain constructors and functions in the interface of `optional` perform a 'perfect forwarding' of arguments:
+
+    template<class... Args> optional(in_place_init_t, Args&&... args);
+    template<class... Args> optional(in_place_init_if_t, bool condition, Args&&... args);
+    template<class... Args> void emplace(Args&&... args);
+    
+On compilers that do not support variadic templates, each of these functions is substituted with two overloads, one forwarding a single argument, the other forwarding zero arguments. This forms the following set:
+
+    template<class Arg> optional(in_place_init_t, Arg&& arg);
+    optional(in_place_init_t);
+    
+    template<class Arg> optional(in_place_init_if_t, bool condition, Arg&& arg);
+    optional(in_place_init_if_t, bool condition);
+    
+    template<class Arg> void emplace(Arg&& arg);
+    void emplace();
+
+On compilers that do not support rvalue references, each of these functions is substituted with three overloadss: taking `const` and non-`const` lvalue reference, and third forwarding zero arguments. This forms the following set:
+
+    template<class Arg> optional(in_place_init_t, const Arg& arg);
+    template<class Arg> optional(in_place_init_t, Arg& arg);
+    optional(in_place_init_t);
+    
+    template<class Arg> optional(in_place_init_if_t, bool condition, const Arg& arg);
+    template<class Arg> optional(in_place_init_if_t, bool condition, Arg& arg);
+    optional(in_place_init_if_t, bool condition);
+    
+    template<class Arg> void emplace(const Arg& arg);
+    template<class Arg> void emplace(Arg& arg);
+    void emplace();
+
+This workaround addressess about 40% of all use cases. If this is insufficient, you need to resort to using [link boost_optional.tutorial.in_place_factories In-Place Factories].    
+[endsect]
 
 [section Optional Reference Binding][#optional_reference_binding]
 

doc/91_relnotes.qbk

@@ -11,6 +11,23 @@
 
 [section:relnotes Release Notes]
 
+[heading Boost Release 1.67]
+
+* Fixed [@https://github.com/boostorg/optional/issues/46 issue #46].
+* Fixed `-Wzero-as-null-pointer-constant` warnings.
+
+
+[heading Boost Release 1.66]
+
+* 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.
+* Changed the implementation of `operator==` to get rid of the `-Wmaybe-uninitialized` false-positive warning from GCC. 
+
+[heading Boost Release 1.63]
+* 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.
+* Syntax `o = {}` now correctly un-initializes optional, just like in `std::optional`.
+* Fixed [@https://svn.boost.org/trac/boost/ticket/12203 Trac #12203].
+* Fixed [@https://svn.boost.org/trac/boost/ticket/12563 Trac #12563].
+
 
 [heading Boost Release 1.62]
 

doc/Jamfile.v2

@@ -46,4 +46,8 @@ boostbook standalone
         <format>docbook:<auto-index-internal>on
     ;
 
-
+###############################################################################
+alias boostdoc ;
+explicit boostdoc ;
+alias boostrelease : standalone ;
+explicit boostrelease ;

doc/html/boost_optional/acknowledgements.html

@@ -116,7 +116,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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

@@ -7,7 +7,7 @@
 <link rel="home" href="../index.html" title="Boost.Optional">
 <link rel="up" href="../index.html" title="Boost.Optional">
 <link rel="prev" href="reference/header__boost_optional_hpp_.html" title="Header &lt;boost/optional.hpp&gt;">
-<link rel="next" href="dependencies_and_portability/optional_reference_binding.html" title="Optional Reference Binding">
+<link rel="next" href="dependencies_and_portability/emplace_operations_in_older_compilers.html" title="Emplace operations in older compilers">
 </head>
 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
 <table cellpadding="2" width="100%"><tr>
@@ -20,7 +20,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
-<a accesskey="p" href="reference/header__boost_optional_hpp_.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="dependencies_and_portability/optional_reference_binding.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
+<a accesskey="p" href="reference/header__boost_optional_hpp_.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="dependencies_and_portability/emplace_operations_in_older_compilers.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
 </div>
 <div class="section">
 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
@@ -29,6 +29,8 @@
 </h2></div></div></div>
 <div class="toc"><dl class="toc">
 <dt><span class="section"><a href="dependencies_and_portability.html#boost_optional.dependencies_and_portability.dependencies">Dependencies</a></span></dt>
+<dt><span class="section"><a href="dependencies_and_portability/emplace_operations_in_older_compilers.html">Emplace
+      operations in older compilers</a></span></dt>
 <dt><span class="section"><a href="dependencies_and_portability/optional_reference_binding.html">Optional
       Reference Binding</a></span></dt>
 </dl></div>
@@ -75,7 +77,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
@@ -83,7 +86,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
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doc/html/boost_optional/dependencies_and_portability/emplace_operations_in_older_compilers.html

@@ -0,0 +1,91 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<title>Emplace operations in older compilers</title>
+<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css">
+<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
+<link rel="home" href="../../index.html" title="Boost.Optional">
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+<table cellpadding="2" width="100%"><tr>
+<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td>
+<td align="center"><a href="../../../../../../index.html">Home</a></td>
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+<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
+<td align="center"><a href="../../../../../../more/index.htm">More</a></td>
+</tr></table>
+<hr>
+<div class="spirit-nav">
+<a accesskey="p" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="optional_reference_binding.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
+</div>
+<div class="section">
+<div class="titlepage"><div><div><h3 class="title">
+<a name="boost_optional.dependencies_and_portability.emplace_operations_in_older_compilers"></a><a class="link" href="emplace_operations_in_older_compilers.html" title="Emplace operations in older compilers">Emplace
+      operations in older compilers</a>
+</h3></div></div></div>
+<p>
+        <a name="optional_emplace_workaround"></a>Certain constructors and functions
+        in the interface of <code class="computeroutput"><span class="identifier">optional</span></code>
+        perform a 'perfect forwarding' of arguments:
+      </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
+</pre>
+<p>
+        On compilers that do not support variadic templates, each of these functions
+        is substituted with two overloads, one forwarding a single argument, the
+        other forwarding zero arguments. This forms the following set:
+      </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">);</span>
+
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">);</span>
+
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">();</span>
+</pre>
+<p>
+        On compilers that do not support rvalue references, each of these functions
+        is substituted with three overloadss: taking <code class="computeroutput"><span class="keyword">const</span></code>
+        and non-<code class="computeroutput"><span class="keyword">const</span></code> lvalue reference,
+        and third forwarding zero arguments. This forms the following set:
+      </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">);</span>
+
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">);</span>
+
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
+<span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">();</span>
+</pre>
+<p>
+        This workaround addressess about 40% of all use cases. If this is insufficient,
+        you need to resort to using <a class="link" href="../tutorial/in_place_factories.html" title="In-Place Factories">In-Place
+        Factories</a>.
+      </p>
+</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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
+</div></td>
+</tr></table>
+<hr>
+<div class="spirit-nav">
+<a accesskey="p" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="optional_reference_binding.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
+</div>
+</body>
+</html>

doc/html/boost_optional/dependencies_and_portability/optional_reference_binding.html

@@ -6,7 +6,7 @@
 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
 <link rel="home" href="../../index.html" title="Boost.Optional">
 <link rel="up" href="../dependencies_and_portability.html" title="Dependencies and Portability">
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+<link rel="prev" href="emplace_operations_in_older_compilers.html" title="Emplace operations in older compilers">
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@@ -20,7 +20,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
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+<a accesskey="p" href="emplace_operations_in_older_compilers.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../relnotes.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
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@@ -93,7 +93,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
@@ -101,7 +102,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
-<a accesskey="p" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../relnotes.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
+<a accesskey="p" href="emplace_operations_in_older_compilers.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../dependencies_and_portability.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../relnotes.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
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doc/html/boost_optional/quick_start.html

@@ -155,7 +155,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +61,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +61,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +80,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +50,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +49,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +46,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +33,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +52,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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_hpp_/detailed_semantics___free_functions.html

@@ -47,6 +47,19 @@
 </pre>
             </li>
 </ul></div>
+<p>
+          <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
+        </p>
+<a name="reference_make_optional_rvalue"></a><div class="blockquote"><blockquote class="blockquote"><p>
+            <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;</span>
+            <span class="identifier">make_optional</span><span class="special">(</span>
+            <span class="identifier">T</span> <span class="special">&amp;&amp;</span>
+            <span class="identifier">v</span> <span class="special">)</span></code>
+          </p></blockquote></div>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
+              <span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">v</span><span class="special">))</span></code> for the <span class="emphasis"><em>deduced</em></span>
+              type <code class="computeroutput"><span class="identifier">T</span></code> of <code class="computeroutput"><span class="identifier">v</span></code>.
+            </li></ul></div>
 <p>
           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
         </p>
@@ -73,6 +86,19 @@
 </pre>
             </li>
 </ul></div>
+<p>
+          <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
+        </p>
+<a name="reference_make_optional_bool_rvalue"></a><div class="blockquote"><blockquote class="blockquote"><p>
+            <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;</span>
+            <span class="identifier">make_optional</span><span class="special">(</span>
+            <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">T</span> <span class="special">&amp;&amp;</span> <span class="identifier">v</span>
+            <span class="special">)</span></code>
+          </p></blockquote></div>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
+              <span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;(</span><span class="identifier">condition</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">v</span><span class="special">))</span></code> for the <span class="emphasis"><em>deduced</em></span>
+              type <code class="computeroutput"><span class="identifier">T</span></code> of <code class="computeroutput"><span class="identifier">v</span></code>.
+            </li></ul></div>
 <p>
           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
         </p>
@@ -481,7 +507,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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_hpp_/detailed_semantics___optional_references.html

@@ -501,7 +501,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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_hpp_/detailed_semantics___optional_values.html

@@ -403,6 +403,94 @@
 </pre>
             </li>
 </ul></div>
+<p>
+          <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
+        </p>
+<a name="reference_optional_in_place_init"></a><div class="blockquote"><blockquote class="blockquote"><p>
+            <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span>
+            <span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">ars</span>
+            <span class="special">);</span></code>
+          </p></blockquote></div>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
+<li class="listitem">
+              <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_constructible_v</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...&gt;</span></code> is <code class="computeroutput"><span class="keyword">true</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Effect:</strong></span> Initializes the contained
+              value as if direct-non-list-initializing an object of type <code class="computeroutput"><span class="identifier">T</span></code> with the arguments <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">Args</span><span class="special">&gt;(</span><span class="identifier">args</span><span class="special">)...</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Throws:</strong></span> Any exception thrown by the
+              selected constructor of <code class="computeroutput"><span class="identifier">T</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
+              need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>.
+              On compilers that do not suppor variadic templates or rvalue references,
+              this constuctor is available in limited functionality. For details
+              <a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Example:</strong></span>
+<pre class="programlisting"><span class="comment">// creates an std::mutex using its default constructor</span>
+<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">&gt;</span> <span class="identifier">om</span> <span class="special">{</span><span class="identifier">in_place_init</span><span class="special">};</span>
+<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">om</span><span class="special">);</span>
+
+<span class="comment">// creates a unique_lock by calling unique_lock(*om, std::defer_lock)</span>
+<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">&gt;&gt;</span> <span class="identifier">ol</span> <span class="special">{</span><span class="identifier">in_place_init</span><span class="special">,</span> <span class="special">*</span><span class="identifier">om</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">defer_lock</span><span class="special">};</span>
+<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ol</span><span class="special">);</span>
+<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">ol</span><span class="special">-&gt;</span><span class="identifier">owns_lock</span><span class="special">());</span>
+</pre>
+            </li>
+</ul></div>
+<p>
+          <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
+        </p>
+<a name="reference_optional_in_place_init_if"></a><div class="blockquote"><blockquote class="blockquote"><p>
+            <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span>
+            <span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span>
+            <span class="identifier">Args</span><span class="special">&amp;&amp;...</span>
+            <span class="identifier">ars</span> <span class="special">);</span></code>
+          </p></blockquote></div>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
+<li class="listitem">
+              <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_constructible_v</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...&gt;</span></code> is <code class="computeroutput"><span class="keyword">true</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Effect:</strong></span> If <code class="computeroutput"><span class="identifier">condition</span></code>
+              is <code class="computeroutput"><span class="keyword">true</span></code>, initializes the
+              contained value as if direct-non-list-initializing an object of type
+              <code class="computeroutput"><span class="identifier">T</span></code> with the arguments
+              <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">Args</span><span class="special">&gt;(</span><span class="identifier">args</span><span class="special">)...</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">condition</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Throws:</strong></span> Any exception thrown by the
+              selected constructor of <code class="computeroutput"><span class="identifier">T</span></code>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
+              need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>.
+              On compilers that do not suppor variadic templates or rvalue references,
+              this constuctor is available in limited functionality. For details
+              <a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
+            </li>
+<li class="listitem">
+              <span class="bold"><strong>Example:</strong></span>
+<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;&gt;</span> <span class="identifier">ov1</span> <span class="special">{</span><span class="identifier">in_place_init_if</span><span class="special">,</span> <span class="keyword">false</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="string">"A"</span><span class="special">};</span>
+<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">ov1</span><span class="special">);</span>
+
+<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;&gt;</span> <span class="identifier">ov2</span> <span class="special">{</span><span class="identifier">in_place_init_if</span><span class="special">,</span> <span class="keyword">true</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="string">"A"</span><span class="special">};</span>
+<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ov2</span><span class="special">);</span>
+<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ov2</span><span class="special">-&gt;</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">3</span><span class="special">);</span>
+</pre>
+            </li>
+</ul></div>
 <p>
           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
         </p>
@@ -1037,15 +1125,8 @@
               <span class="bold"><strong>Notes:</strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
               need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>
               or <code class="computeroutput"><span class="identifier">MoveAssignable</span></code>.
-              On compilers that do not support variadic templates, the signature
-              falls back to two overloads:<code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span>
-              <span class="identifier">Arg</span><span class="special">&gt;</span>
-              <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">)</span></code> and <code class="computeroutput"><span class="keyword">void</span>
-              <span class="identifier">emplace</span><span class="special">()</span></code>.
-              On compilers that do not support rvalue references, the signature falls
-              back to three overloads: taking <code class="computeroutput"><span class="keyword">const</span></code>
-              and non-<code class="computeroutput"><span class="keyword">const</span></code> lvalue reference,
-              and third with empty function argument list.
+              On compilers that do not suppor variadic templates or rvalue references,
+              this function is available in limited functionality. For details <a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
             </li>
 <li class="listitem">
               <span class="bold"><strong>Example:</strong></span>
@@ -1570,7 +1651,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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_hpp_/header_optional_in_place_init.html

@@ -0,0 +1,62 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<title>Initialization tags</title>
+<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css">
+<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
+<link rel="home" href="../../../index.html" title="Boost.Optional">
+<link rel="up" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
+<link rel="prev" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
+<link rel="next" href="header_optional_optional_values.html" title="Optional Values">
+</head>
+<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
+<table cellpadding="2" width="100%"><tr>
+<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td>
+<td align="center"><a href="../../../../../../../index.html">Home</a></td>
+<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td>
+<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
+<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
+<td align="center"><a href="../../../../../../../more/index.htm">More</a></td>
+</tr></table>
+<hr>
+<div class="spirit-nav">
+<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_values.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
+</div>
+<div class="section">
+<div class="titlepage"><div><div><h4 class="title">
+<a name="boost_optional.reference.header__boost_optional_optional_hpp_.header_optional_in_place_init"></a><a class="link" href="header_optional_in_place_init.html" title="Initialization tags">Initialization
+        tags</a>
+</h4></div></div></div>
+<a name="reference_in_place_init"></a><a name="reference_in_place_init_if"></a><pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
+
+<span class="keyword">class</span> <span class="identifier">in_place_init_t</span> <span class="special">{</span> <span class="comment">/* see below */</span> <span class="special">}</span> <span class="special">;</span>
+<span class="keyword">const</span> <span class="identifier">in_place_init_t</span> <span class="identifier">in_place_init</span> <span class="special">(</span> <span class="comment">/* see below */</span> <span class="special">)</span> <span class="special">;</span>
+
+<span class="keyword">class</span> <span class="identifier">in_place_init_if_t</span> <span class="special">{</span> <span class="comment">/*see below*/</span> <span class="special">}</span> <span class="special">;</span>
+<span class="keyword">const</span> <span class="identifier">in_place_init_if_t</span> <span class="identifier">in_place_init_if</span> <span class="special">(</span> <span class="comment">/*see below*/</span> <span class="special">)</span> <span class="special">;</span>
+
+<span class="special">}</span>
+</pre>
+<p>
+          Classes <code class="computeroutput"><span class="identifier">in_place_init_t</span></code>
+          and <code class="computeroutput"><span class="identifier">in_place_init_if_t</span></code>
+          are empty clsses. Their purpose is to control overload resolution in the
+          initialization of optional objects. They are empty, trivially copyable
+          classes with disabled default constructor.
+        </p>
+</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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
+</div></td>
+</tr></table>
+<hr>
+<div class="spirit-nav">
+<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_values.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
+</div>
+</body>
+</html>

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

@@ -100,7 +100,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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_hpp_/header_optional_optional_values.html

@@ -6,7 +6,7 @@
 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
 <link rel="home" href="../../../index.html" title="Boost.Optional">
 <link rel="up" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
-<link rel="prev" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
+<link rel="prev" href="header_optional_in_place_init.html" title="Initialization tags">
 <link rel="next" href="header_optional_optional_refs.html" title="Optional References">
 </head>
 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
@@ -20,7 +20,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
-<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
+<a accesskey="p" href="header_optional_in_place_init.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
 </div>
 <div class="section">
 <div class="titlepage"><div><div><h4 class="title">
@@ -47,7 +47,6 @@
 
     <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&amp;&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_move_value"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
 
-    <span class="comment">// [new in 1.34]</span>
     <span class="identifier">optional</span> <span class="special">(</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_bool_value"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
 
     <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_optional"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
@@ -58,6 +57,10 @@
 
     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&gt;&amp;&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_move_constructor_other_optional"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
 
+    <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_in_place_init"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
+
+    <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_in_place_init_if"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
+
     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
 
     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
@@ -127,7 +130,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
@@ -135,7 +139,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
-<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
+<a accesskey="p" href="header_optional_in_place_init.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
 </div>
 </body>
 </html>

doc/html/boost_optional/reference/io_header.html

@@ -58,7 +58,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/io_header/io_semantics.html

@@ -98,7 +98,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/relnotes.html

@@ -28,6 +28,48 @@
 </h2></div></div></div>
 <h4>
 <a name="boost_optional.relnotes.h0"></a>
+      <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_66"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_66">Boost
+      Release 1.66</a>
+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
+<li class="listitem">
+          On newer compilers <code class="computeroutput"><span class="identifier">optional</span></code>
+          is now trivially-copyable for scalar <code class="computeroutput"><span class="identifier">T</span></code>s.
+          This uses a different storage (just <code class="computeroutput"><span class="identifier">T</span></code>
+          rather than <code class="computeroutput"><span class="identifier">aligned_storage</span></code>).
+          We require the compiler to support defaulted functions.
+        </li>
+<li class="listitem">
+          Changed the implementation of <code class="computeroutput"><span class="keyword">operator</span><span class="special">==</span></code> to get rid of the <code class="computeroutput"><span class="special">-</span><span class="identifier">Wmaybe</span><span class="special">-</span><span class="identifier">uninitialized</span></code> false-positive warning
+          from GCC.
+        </li>
+</ul></div>
+<h4>
+<a name="boost_optional.relnotes.h1"></a>
+      <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_63"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_63">Boost
+      Release 1.63</a>
+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
+<li class="listitem">
+          Added two new in-place constructors. They work similarly to <code class="computeroutput"><span class="identifier">emplace</span><span class="special">()</span></code>
+          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.
+        </li>
+<li class="listitem">
+          Syntax <code class="computeroutput"><span class="identifier">o</span> <span class="special">=</span>
+          <span class="special">{}</span></code> now correctly un-initializes
+          optional, just like in <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">optional</span></code>.
+        </li>
+<li class="listitem">
+          Fixed <a href="https://svn.boost.org/trac/boost/ticket/12203" target="_top">Trac #12203</a>.
+        </li>
+<li class="listitem">
+          Fixed <a href="https://svn.boost.org/trac/boost/ticket/12563" target="_top">Trac #12563</a>.
+        </li>
+</ul></div>
+<h4>
+<a name="boost_optional.relnotes.h2"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_62"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_62">Boost
       Release 1.62</a>
     </h4>
@@ -35,7 +77,7 @@
           Fixed <a href="https://svn.boost.org/trac/boost/ticket/12179" target="_top">Trac #12179</a>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h1"></a>
+<a name="boost_optional.relnotes.h3"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_61"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_61">Boost
       Release 1.61</a>
     </h4>
@@ -78,7 +120,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h2"></a>
+<a name="boost_optional.relnotes.h4"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_60"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_60">Boost
       Release 1.60</a>
     </h4>
@@ -89,7 +131,7 @@
           #11203</a>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h3"></a>
+<a name="boost_optional.relnotes.h5"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_59"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_59">Boost
       Release 1.59</a>
     </h4>
@@ -103,7 +145,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h4"></a>
+<a name="boost_optional.relnotes.h6"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_58"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_58">Boost
       Release 1.58</a>
     </h4>
@@ -139,7 +181,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h5"></a>
+<a name="boost_optional.relnotes.h7"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_57"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_57">Boost
       Release 1.57</a>
     </h4>
@@ -149,7 +191,7 @@
           to fix C++03 compile error on <code class="computeroutput"><span class="identifier">logic_error</span><span class="special">(</span><span class="string">"..."</span><span class="special">)</span></code>"</em></span>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h6"></a>
+<a name="boost_optional.relnotes.h8"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_56"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_56">Boost
       Release 1.56</a>
     </h4>
@@ -206,7 +248,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/design_overview.html

@@ -170,7 +170,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/design_overview/the_interface.html

@@ -173,7 +173,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/design_overview/the_semantics.html

@@ -107,7 +107,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/exception_safety_guarantees.html

@@ -161,7 +161,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/gotchas.html

@@ -98,7 +98,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/gotchas/false_positive_with__wmaybe_uninitialized.html

@@ -55,7 +55,7 @@
           Stack Overflow question</a>) use the following way of initializing
           an optional containing no value:
         </p>
-<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">b</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">make_optional</span><span class="special">(</span><span class="keyword">false</span><span class="special">,</span> <span class="keyword">int</span><span class="special">());</span>
+<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">b</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">make_optional</span><span class="special">(</span><span class="keyword">false</span><span class="special">,</span> <span class="keyword">int</span><span class="special">());</span>
 </pre>
 <p>
           This is obviously redundant, but makes the warning disappear.
@@ -63,7 +63,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/gotchas/mixed_relational_comparisons.html

@@ -45,7 +45,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/gotchas/moved_from__optional_.html

@@ -49,7 +49,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/in_place_factories.html

@@ -183,7 +183,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/io_operators.html

@@ -73,7 +73,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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.html

@@ -103,7 +103,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +133,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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

@@ -29,7 +29,8 @@
 </h3></div></div></div>
 <p>
         Technical details aside, the memory layout of <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code>
-        is more-less this:
+        for a generic <code class="computeroutput"><span class="identifier">T</span></code> is more-less
+        this:
       </p>
 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
 <span class="keyword">class</span> <span class="identifier">optional</span>
@@ -39,8 +40,48 @@
 <span class="special">};</span>
 </pre>
 <p>
-        But for the purpose of this analysis, considering memory layouts, we can
-        think of it as:
+        Lifetime of the <code class="computeroutput"><span class="identifier">T</span></code> inside
+        <code class="computeroutput"><span class="identifier">_storage</span></code> is manually controlled
+        with placement-<code class="computeroutput"><span class="keyword">new</span></code>s and pseudo-destructor
+        calls. However, for scalar <code class="computeroutput"><span class="identifier">T</span></code>s
+        we use a different way of storage, by simply holding a <code class="computeroutput"><span class="identifier">T</span></code>:
+      </p>
+<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
+<span class="keyword">class</span> <span class="identifier">optional</span>
+<span class="special">{</span>
+  <span class="keyword">bool</span> <span class="identifier">_initialized</span><span class="special">;</span>
+  <span class="identifier">T</span> <span class="identifier">_storage</span><span class="special">;</span>
+<span class="special">};</span>
+</pre>
+<p>
+        We call it a <span class="emphasis"><em>direct</em></span> storage. This makes <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code> a
+        trivially-copyable type for scalar <code class="computeroutput"><span class="identifier">T</span></code>s.
+        This only works for compilers that support defaulted functions. On compilers
+        without defaulted functions we still use the direct storage, but <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code> is
+        no longer recognized as trivially-copyable. Apart from scalar types, we leave
+        the programmer a way of customizing her type, so that it is reconized by
+        <code class="computeroutput"><span class="identifier">optional</span></code> as candidate for
+        optimized storage, by specializing type trait <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">opitonal_config</span><span class="special">::</span><span class="identifier">optional_uses_direct_storage_for</span></code>:
+      </p>
+<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">X</span> <span class="comment">// not trivial</span>
+<span class="special">{</span>
+  <span class="identifier">X</span><span class="special">()</span> <span class="special">{}</span>
+<span class="special">};</span>
+
+<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">optional_config</span> <span class="special">{</span>
+
+  <span class="keyword">template</span> <span class="special">&lt;&gt;</span> <span class="keyword">struct</span> <span class="identifier">optional_uses_direct_storage_for</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">&gt;</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">true_type</span> <span class="special">{};</span>
+
+<span class="special">}}</span>
+</pre>
+<h5>
+<a name="boost_optional.tutorial.performance_considerations.h0"></a>
+        <span class="phrase"><a name="boost_optional.tutorial.performance_considerations.controlling_the_size"></a></span><a class="link" href="performance_considerations.html#boost_optional.tutorial.performance_considerations.controlling_the_size">Controlling
+        the size</a>
+      </h5>
+<p>
+        For the purpose of the following analysis, considering memory layouts, we
+        can think of it as:
       </p>
 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
 <span class="keyword">class</span> <span class="identifier">optional</span>
@@ -143,7 +184,7 @@
         <span class="inlinemediaobject"><img src="../../images/opt_align4.png" alt="opt_align4"></span>
       </p>
 <h5>
-<a name="boost_optional.tutorial.performance_considerations.h0"></a>
+<a name="boost_optional.tutorial.performance_considerations.h1"></a>
         <span class="phrase"><a name="boost_optional.tutorial.performance_considerations.optional_function_parameters"></a></span><a class="link" href="performance_considerations.html#boost_optional.tutorial.performance_considerations.optional_function_parameters">Optional
         function parameters</a>
       </h5>
@@ -209,7 +250,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +99,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +95,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +128,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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 +26,8 @@
 <span class="firstname">Fernando Luis</span> <span class="surname">Cacciola Carballal</span>
 </h3></div></div>
 <div><p class="copyright">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal</p></div>
-<div><p class="copyright">Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski</p></div>
+<div><p class="copyright">Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski</p></div>
 <div><div class="legalnotice">
 <a name="optional.legal"></a><p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
@@ -89,6 +90,8 @@
     and Portability</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_optional/dependencies_and_portability.html#boost_optional.dependencies_and_portability.dependencies">Dependencies</a></span></dt>
+<dt><span class="section"><a href="boost_optional/dependencies_and_portability/emplace_operations_in_older_compilers.html">Emplace
+      operations in older compilers</a></span></dt>
 <dt><span class="section"><a href="boost_optional/dependencies_and_portability/optional_reference_binding.html">Optional
       Reference Binding</a></span></dt>
 </dl></dd>
@@ -143,7 +146,7 @@
 </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: September 16, 2016 at 23:43:36 GMT</small></p></td>
+<td align="left"><p><small>Last revised: May 17, 2017 at 23:01:39 GMT</small></p></td>
 <td align="right"><div class="copyright-footer"></div></td>
 </tr></table>
 <hr>

doc/html/optional/reference.html

@@ -75,7 +75,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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

@@ -7,7 +7,7 @@
 <link rel="home" href="../../index.html" title="Boost.Optional">
 <link rel="up" href="../reference.html" title="Reference">
 <link rel="prev" href="../../boost_optional/reference/header__boost_optional_optional_fwd_hpp_.html" title="Header &lt;boost/optional/optional_fwd.hpp&gt;">
-<link rel="next" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_optional_values.html" title="Optional Values">
+<link rel="next" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_in_place_init.html" title="Initialization tags">
 </head>
 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
 <table cellpadding="2" width="100%"><tr>
@@ -20,7 +20,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
-<a accesskey="p" href="../../boost_optional/reference/header__boost_optional_optional_fwd_hpp_.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_optional_values.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
+<a accesskey="p" href="../../boost_optional/reference/header__boost_optional_optional_fwd_hpp_.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_in_place_init.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
 </div>
 <div class="section">
 <div class="titlepage"><div><div><h3 class="title">
@@ -35,6 +35,12 @@
 
 <span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
 
+<span class="keyword">class</span> <span class="identifier">in_place_init_t</span> <span class="special">{</span> <span class="comment">/* see below */</span> <span class="special">}</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_in_place_init.html#reference_in_place_init"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
+<span class="keyword">const</span> <span class="identifier">in_place_init_t</span> <span class="identifier">in_place_init</span> <span class="special">(</span> <span class="comment">/* see below */</span> <span class="special">)</span> <span class="special">;</span>
+
+<span class="keyword">class</span> <span class="identifier">in_place_init_if_t</span> <span class="special">{</span> <span class="comment">/*see below*/</span> <span class="special">}</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_in_place_init.html#reference_in_place_init_if"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
+<span class="keyword">const</span> <span class="identifier">in_place_init_if_t</span> <span class="identifier">in_place_init_if</span> <span class="special">(</span> <span class="comment">/*see below*/</span> <span class="special">)</span> <span class="special">;</span>
+
 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
 <span class="keyword">class</span> <span class="identifier">optional</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/header_optional_optional_values.html#reference_operator_template"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
 
@@ -59,8 +65,12 @@
 
 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_make_optional_value"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
 
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;</span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="identifier">T</span> <span class="special">&amp;&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_make_optional_rvalue"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
+
 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_make_optional_bool_value"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
 
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">decay_t</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&gt;</span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">T</span> <span class="special">&amp;&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_make_optional_bool_rvalue"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
+
 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="keyword">auto</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reference_const_type</span> <span class="identifier">def</span> <span class="special">)</span> <span class="special">-&gt;</span> <span class="keyword">typename</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reference_const_type</span><span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_free_get_value_or"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
 
 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="keyword">auto</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reference_type</span> <span class="identifier">def</span> <span class="special">)</span> <span class="special">-&gt;</span> <span class="keyword">typename</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reference_type</span> <span class="special">;</span> <a class="link" href="../../boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___free_functions.html#reference_free_get_value_or"><span class="inlinemediaobject"><img src="../../images/callouts/R.png" alt="R"></span></a>
@@ -87,7 +97,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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>
@@ -95,7 +106,7 @@
 </tr></table>
 <hr>
 <div class="spirit-nav">
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doc/html/optional/tutorial.html

@@ -139,7 +139,8 @@
 </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 &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
+<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2017 Andrzej
+      Krzemie&#324;ski<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/experimental_traits.hpp

@@ -0,0 +1,98 @@
+// 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
+
+#ifndef BOOST_OPTIONAL_DETAIL_EXPERIMENTAL_TRAITS_04NOV2017_HPP
+#define BOOST_OPTIONAL_DETAIL_EXPERIMENTAL_TRAITS_04NOV2017_HPP
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+#include <boost/type_traits.hpp>
+
+namespace boost { namespace optional_detail {
+  
+// The condition to use POD implementation
+
+#ifdef BOOST_OPTIONAL_CONFIG_NO_POD_SPEC
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif defined BOOST_OPTIONAL_CONFIG_NO_SPEC_FOR_TRIVIAL_TYPES
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_CONSTRUCTOR
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_MOVE_ASSIGN
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_MOVE_CONSTRUCTOR
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_COPY
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_ASSIGN
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif !defined BOOST_HAS_TRIVIAL_DESTRUCTOR
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#elif BOOST_WORKAROUND(BOOST_GCC, < 50000)
+# define BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+#endif
+
+#if __cplusplus >= 201103L
+#  if BOOST_WORKAROUND(BOOST_GCC, >= 50000)
+#    define BOOST_OPTIONAL_DETAIL_USE_STD_TYPE_TRAITS
+#  elif (defined BOOST_CLANG)
+#    define BOOST_OPTIONAL_DETAIL_USE_STD_TYPE_TRAITS
+#  endif
+#endif  
+
+
+#ifndef BOOST_OPTIONAL_DETAIL_USE_STD_TYPE_TRAITS
+#  define BOOST_OPTIONAL_DETAIL_HAS_TRIVIAL_CTOR(T) BOOST_HAS_TRIVIAL_CONSTRUCTOR(T)
+#else
+#  define BOOST_OPTIONAL_DETAIL_HAS_TRIVIAL_CTOR(T) std::is_trivially_default_constructible<T>::value
+#endif
+  
+  
+  
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+template <typename T>
+struct is_type_trivially_copyable
+  : boost::conditional<(boost::has_trivial_copy_constructor<T>::value &&
+                        boost::has_trivial_move_constructor<T>::value &&
+                        boost::has_trivial_destructor<T>::value &&
+                        boost::has_trivial_move_assign<T>::value &&
+                        boost::has_trivial_assign<T>::value),
+                        boost::true_type, boost::false_type>::type
+{};
+#else
+template <typename T>
+struct is_type_trivially_copyable
+: boost::conditional<(boost::is_scalar<T>::value && !boost::is_const<T>::value && !boost::is_volatile<T>::value),
+                     boost::true_type, boost::false_type>::type
+{};
+#endif
+
+
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES  
+template <typename T>
+struct optional_uses_direct_storage_for_
+  : boost::conditional< (is_type_trivially_copyable<T>::value && BOOST_OPTIONAL_DETAIL_HAS_TRIVIAL_CTOR(T)) ||
+                        (boost::is_scalar<T>::value && !boost::is_const<T>::value && !boost::is_volatile<T>::value)
+                      , boost::true_type, boost::false_type>::type
+{};
+#else
+template <typename T>
+struct optional_uses_direct_storage_for_
+  : boost::conditional<(boost::is_scalar<T>::value && !boost::is_const<T>::value && !boost::is_volatile<T>::value)
+                      , boost::true_type, boost::false_type>::type
+{};
+#endif
+
+
+}} // boost::optional_detail
+
+#endif

include/boost/optional/detail/old_optional_implementation.hpp

@@ -147,7 +147,7 @@ class optional_base : public optional_tag
     }
 #endif
 
-    // Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialzed optional<T>.
+    // Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional<T>.
     // Can throw if T::T(T const&) does
     optional_base ( bool cond, argument_type val )
       :
@@ -730,7 +730,7 @@ class optional : public optional_detail::optional_base<T>
   explicit optional ( Expr&& expr, 
                       BOOST_DEDUCED_TYPENAME boost::disable_if_c<
                         (boost::is_base_of<optional_detail::optional_tag, BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type>::value) || 
-                        boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type, none_t>::value >::type* = 0 
+                        boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type, none_t>::value, bool >::type = true 
   ) 
     : base(boost::forward<Expr>(expr),boost::addressof(expr)) 
     {optional_detail::prevent_binding_rvalue_ref_to_optional_lvalue_ref<T, Expr&&>();}
@@ -746,12 +746,12 @@ class optional : public optional_detail::optional_base<T>
     optional ( optional const& rhs ) : base( static_cast<base const&>(rhs) ) {}
 
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
-	// Creates a deep move of another optional<T>
-	// Can throw if T::T(T&&) does
-	optional ( optional && rhs ) 
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
-	  : base( boost::move(rhs) ) 
-	{}
+    // Creates a deep move of another optional<T>
+    // Can throw if T::T(T&&) does
+    optional ( optional && rhs )
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
+      : base( boost::move(rhs) )
+    {}
 
 #endif
    // No-throw (assuming T::~T() doesn't)
@@ -819,7 +819,7 @@ class optional : public optional_detail::optional_base<T>
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
     // Assigns from another optional<T> (deep-moves the rhs value)
     optional& operator= ( optional && rhs ) 
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
       {
         this->assign( static_cast<base &&>(rhs) ) ;
         return *this ;
@@ -892,7 +892,7 @@ class optional : public optional_detail::optional_base<T>
 #endif
 
     void swap( optional & arg )
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
       {
         // allow for Koenig lookup
         boost::swap(*this, arg);

include/boost/optional/detail/optional_aligned_storage.hpp

@@ -25,12 +25,8 @@ template <class T>
 class aligned_storage
 {
     // Borland ICEs if unnamed unions are used for this!
-    union
-    // This works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
-#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
-    __attribute__((__may_alias__))
-#endif
-    dummy_u
+    // 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) ];
         BOOST_DEDUCED_TYPENAME type_with_alignment<
@@ -48,24 +44,24 @@ class aligned_storage
 #endif
 
 #if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
-	// This workaround is supposed to silence GCC warnings about broken strict aliasing rules
-	T const* ptr_ref() const
-	{
-		union { void const* ap_pvoid; T const* as_ptype; } caster = { address() };
-		return caster.as_ptype;
-	}
-	T *      ptr_ref()
-	{
-		union { void* ap_pvoid; T* as_ptype; } caster = { address() };
-		return caster.as_ptype;
-	}
+    // This workaround is supposed to silence GCC warnings about broken strict aliasing rules
+    T const* ptr_ref() const
+    {
+        union { void const* ap_pvoid; T const* as_ptype; } caster = { address() };
+        return caster.as_ptype;
+    }
+    T *      ptr_ref()
+    {
+        union { void* ap_pvoid; T* as_ptype; } caster = { address() };
+        return caster.as_ptype;
+    }
 #else
-	T const* ptr_ref() const { return static_cast<T const*>(address()); }
-	T *      ptr_ref()       { return static_cast<T *>     (address()); }
+    T const* ptr_ref() const { return static_cast<T const*>(address()); }
+    T *      ptr_ref()       { return static_cast<T *>     (address()); }
 #endif
 
-	T const& ref() const { return *ptr_ref(); }
-	T &      ref()       { return *ptr_ref(); }
+    T const& ref() const { return *ptr_ref(); }
+    T &      ref()       { return *ptr_ref(); }
   
 } ;
 

include/boost/optional/detail/optional_config.hpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
-// Copyright (C) 2015 Andrzej Krzemienski.
+// Copyright (C) 2015 - 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
@@ -44,11 +44,11 @@
 # define BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
 #endif
 
-#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
-// GCC since 3.3 has may_alias attribute that helps to alleviate optimizer issues with
-// regard to violation of the strict aliasing rules. The optional< T > storage type is marked
-// with this attribute in order to let the compiler know that it will alias objects of type T
-// and silence compilation warnings.
+#if !defined(BOOST_NO_MAY_ALIAS)
+// GCC since 3.3 and some other compilers have may_alias attribute that helps to alleviate
+// optimizer issues with regard to violation of the strict aliasing rules. The optional< T >
+// storage type is marked with this attribute in order to let the compiler know that it will
+// alias objects of type T and silence compilation warnings.
 # define BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS
 #endif
 
@@ -96,4 +96,40 @@
 
 #endif // defined(__GNUC__)
 
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500) && !defined(__SUNPRO_CC)
+  // this condition is a copy paste from is_constructible.hpp
+  // I also disable SUNPRO, as it seems not to support type_traits correctly
+#else
+# define BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT
+#endif
+
+#if defined __SUNPRO_CC
+# define BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+#elif (defined _MSC_FULL_VER) && (_MSC_FULL_VER < 190023026)
+# define BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+#elif defined BOOST_GCC && !defined BOOST_GCC_CXX11
+# define BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+#elif defined BOOST_GCC_VERSION && BOOST_GCC_VERSION < 40800
+# define BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+#endif
+
+
+// Detect suport for defaulting move operations
+// (some older compilers implement rvalue references,
+// defaulted funcitons but move operations are not special members and cannot be defaulted)
+
+#ifdef BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
+# define BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+#elif BOOST_WORKAROUND(BOOST_MSVC, < 1900)
+# define BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+#elif BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40600)
+# define BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+#endif
+
+
+#ifdef BOOST_OPTIONAL_CONFIG_NO_DIRECT_STORAGE_SPEC
+# define BOOST_OPTIONAL_DETAIL_NO_DIRECT_STORAGE_SPEC
+#endif
+
+
 #endif // header guard

include/boost/optional/detail/optional_reference_spec.hpp

@@ -44,6 +44,23 @@ BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type& forward_reference(T&& r
 
 #endif // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
 
+
+template <class T>
+struct is_const_integral
+{
+  static const bool value = boost::is_const<T>::value && boost::is_integral<T>::value;
+};
+
+template <class T>
+struct is_const_integral_bad_for_conversion
+{
+#if (!defined BOOST_OPTIONAL_CONFIG_ALLOW_BINDING_TO_RVALUES) && (defined BOOST_OPTIONAL_CONFIG_NO_PROPER_CONVERT_FROM_CONST_INT)
+  static const bool value = boost::is_const<T>::value && boost::is_integral<T>::value;
+#else
+  static const bool value = false;
+#endif
+};
+
 template <class From>
 void prevent_assignment_from_false_const_integral()
 {
@@ -51,12 +68,13 @@ void prevent_assignment_from_false_const_integral()
 #ifdef BOOST_OPTIONAL_CONFIG_NO_PROPER_ASSIGN_FROM_CONST_INT
     // MSVC compiler without rvalue refernces: we need to disable the asignment from
     // const integral lvalue reference, as it may be an invalid temporary
-    BOOST_STATIC_ASSERT_MSG(!(boost::is_const<From>::value && boost::is_integral<From>::value), 
+    BOOST_STATIC_ASSERT_MSG(!is_const_integral<From>::value, 
                             "binding const lvalue references to integral types is disabled in this compiler");
 #endif
 #endif   
 }
 
+
 template <class T>
 struct is_optional_
 {
@@ -75,6 +93,21 @@ struct is_no_optional
   static const bool value = !is_optional_<BOOST_DEDUCED_TYPENAME boost::decay<T>::type>::value;
 };
 
+
+template <class T, class U>
+  struct is_same_decayed
+  {
+    static const bool value = ::boost::is_same<T, BOOST_DEDUCED_TYPENAME ::boost::remove_reference<U>::type>::value
+                           || ::boost::is_same<T, const BOOST_DEDUCED_TYPENAME ::boost::remove_reference<U>::type>::value;
+  };
+
+template <class T, class U>
+struct no_unboxing_cond
+{
+  static const bool value = is_no_optional<U>::value && !is_same_decayed<T, U>::value;
+};
+
+
 } // namespace detail
 
 template <class T>
@@ -94,13 +127,21 @@ public:
     optional(none_t) BOOST_NOEXCEPT : ptr_() {}  
 
     template <class U>
-        explicit optional(const optional<U&>& rhs) BOOST_NOEXCEPT : ptr_(rhs.ptr_) {}
-    optional(const optional& rhs) BOOST_NOEXCEPT : ptr_(rhs.ptr_) {}
+        explicit optional(const optional<U&>& rhs) BOOST_NOEXCEPT : ptr_(rhs.get_ptr()) {}
+    optional(const optional& rhs) BOOST_NOEXCEPT : ptr_(rhs.get_ptr()) {}
     
-
-    optional& operator=(const optional& rhs) BOOST_NOEXCEPT { ptr_ = rhs.ptr_; return *this; }
+    // the following two implement a 'conditionally explicit' constructor: condition is a hack for buggy compilers with srewed conversion construction from const int
     template <class U>
-        optional& operator=(const optional<U&>& rhs) BOOST_NOEXCEPT { ptr_ = rhs.ptr_; return *this; }
+      explicit optional(U& rhs, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::is_same_decayed<T, U>::value && detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
+      : ptr_(boost::addressof(rhs)) {}
+      
+    template <class U>
+      optional(U& rhs, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::is_same_decayed<T, U>::value && !detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
+      : ptr_(boost::addressof(rhs)) {}
+
+    optional& operator=(const optional& rhs) BOOST_NOEXCEPT { ptr_ = rhs.get_ptr(); return *this; }
+    template <class U>
+        optional& operator=(const optional<U&>& rhs) BOOST_NOEXCEPT { ptr_ = rhs.get_ptr(); return *this; }
     optional& operator=(none_t) BOOST_NOEXCEPT { ptr_ = 0; return *this; }
     
     
@@ -121,12 +162,14 @@ public:
     
 #ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES   
  
+    optional(T&& /* rhs */) BOOST_NOEXCEPT { detail::prevent_binding_rvalue<T&&>(); }
+    
     template <class R>
-        optional(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) BOOST_NOEXCEPT
+        optional(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::no_unboxing_cond<T, R>, bool>::type = true) BOOST_NOEXCEPT
         : ptr_(boost::addressof(r)) { detail::prevent_binding_rvalue<R>(); }
         
     template <class R>
-        optional(bool cond, R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) BOOST_NOEXCEPT
+        optional(bool cond, R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
         : ptr_(cond ? boost::addressof(r) : 0) { detail::prevent_binding_rvalue<R>(); }
         
     template <class R>
@@ -134,19 +177,19 @@ public:
         operator=(R&& r) BOOST_NOEXCEPT { detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); return *this; }
         
     template <class R>
-        void emplace(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) BOOST_NOEXCEPT
+        void emplace(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
         { detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); }
         
     template <class R>
-      T& get_value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) const BOOST_NOEXCEPT
+      T& get_value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) const BOOST_NOEXCEPT
       { detail::prevent_binding_rvalue<R>(); return ptr_ ? *ptr_ : r; }
       
     template <class R>
-        T& value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) const BOOST_NOEXCEPT
+        T& value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) const BOOST_NOEXCEPT
         { detail::prevent_binding_rvalue<R>(); return ptr_ ? *ptr_ : r; }
         
     template <class R>
-      void reset(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R> >::type* = 0) BOOST_NOEXCEPT
+      void reset(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
       { detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); }
       
     template <class F>
@@ -154,34 +197,41 @@ public:
       
 #else  // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
 
+    
+    // the following two implement a 'conditionally explicit' constructor
     template <class U>
-        optional(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) BOOST_NOEXCEPT : ptr_(boost::addressof(v)) { }
+      explicit optional(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::no_unboxing_cond<T, U>::value && detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
+      : ptr_(boost::addressof(v)) { }
+      
+    template <class U>
+      optional(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::no_unboxing_cond<T, U>::value && !detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
+      : ptr_(boost::addressof(v)) { }
         
     template <class U>
-        optional(bool cond, U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) BOOST_NOEXCEPT : ptr_(cond ? boost::addressof(v) : 0) {}
+      optional(bool cond, U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT : ptr_(cond ? boost::addressof(v) : 0) {}
 
     template <class U>
-        BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, optional<T&>&>::type
-        operator=(U& v) BOOST_NOEXCEPT
-        {
-            detail::prevent_assignment_from_false_const_integral<U>();
-            ptr_ = boost::addressof(v); return *this;
-        }
+      BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, optional<T&>&>::type
+      operator=(U& v) BOOST_NOEXCEPT
+      {
+        detail::prevent_assignment_from_false_const_integral<U>();
+        ptr_ = boost::addressof(v); return *this;
+      }
 
     template <class U>
-        void emplace(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) BOOST_NOEXCEPT
+        void emplace(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT
         { ptr_ = boost::addressof(v); }
         
     template <class U>
-      T& get_value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) const BOOST_NOEXCEPT
+      T& get_value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) const BOOST_NOEXCEPT
       { return ptr_ ? *ptr_ : v; }
       
     template <class U>
-        T& value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) const BOOST_NOEXCEPT
+        T& value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) const BOOST_NOEXCEPT
         { return ptr_ ? *ptr_ : v; }
         
     template <class U>
-      void reset(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U> >::type* = 0) BOOST_NOEXCEPT
+      void reset(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT
       { ptr_ = boost::addressof(v); }
       
     template <class F>

include/boost/optional/detail/optional_relops.hpp

@@ -26,7 +26,7 @@ namespace boost {
 template<class T>
 inline
 bool operator == ( optional<T> const& x, optional<T> const& y )
-{ return equal_pointees(x,y); }
+{ return bool(x) && bool(y) ? *x == *y : bool(x) == bool(y); }
 
 template<class T>
 inline

include/boost/optional/detail/optional_trivially_copyable_base.hpp

@@ -0,0 +1,499 @@
+// trivilally-copyable version of the storage
+
+template<class T>
+class tc_optional_base : public optional_tag
+{
+  private :
+
+    typedef tc_optional_base<T> this_type ;
+
+  protected :
+
+    typedef T value_type ;
+
+  protected:
+    typedef T &       reference_type ;
+    typedef T const&  reference_const_type ;
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    typedef T &&  rval_reference_type ;
+    typedef T &&  reference_type_of_temporary_wrapper ;
+#endif
+    typedef T *         pointer_type ;
+    typedef T const*    pointer_const_type ;
+    typedef T const&    argument_type ;
+
+    tc_optional_base()
+      :
+      m_initialized(false) {}
+
+    tc_optional_base ( none_t )
+      :
+      m_initialized(false) {}
+
+    tc_optional_base ( argument_type val )
+      :
+      m_initialized(true), m_storage(val) {}
+
+    tc_optional_base ( bool cond, argument_type val )
+      :
+      m_initialized(cond), m_storage(val) {}
+
+    // tc_optional_base ( tc_optional_base const& ) = default;
+
+
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+
+    template<class Expr, class PtrExpr>
+    explicit tc_optional_base ( Expr&& expr, PtrExpr const* tag )
+      :
+      m_initialized(false)
+    {
+      construct(boost::forward<Expr>(expr),tag);
+    }
+
+#else
+    // This is used for both converting and in-place constructions.
+    // Derived classes use the 'tag' to select the appropriate
+    // implementation (the correct 'construct()' overload)
+    template<class Expr>
+    explicit tc_optional_base ( Expr const& expr, Expr const* tag )
+      :
+      m_initialized(false)
+    {
+      construct(expr,tag);
+    }
+
+#endif
+
+    // tc_optional_base& operator= ( tc_optional_base const& ) = default;
+    // ~tc_optional_base() = default;
+
+    // Assigns from another optional<T> (deep-copies the rhs value)
+    void assign ( tc_optional_base const& rhs ) 
+    {
+      this->operator=(rhs);
+    }
+
+    // Assigns from another _convertible_ optional<U> (deep-copies the rhs value)
+    template<class U>
+    void assign ( optional<U> const& rhs )
+    {
+      if ( rhs.is_initialized() )
+#ifndef BOOST_OPTIONAL_CONFIG_RESTORE_ASSIGNMENT_OF_NONCONVERTIBLE_TYPES
+        m_storage = rhs.get();
+#else
+        m_storage = static_cast<value_type>(rhs.get());
+#endif
+          
+      m_initialized = rhs.is_initialized();
+    }
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    // move-assigns from another _convertible_ optional<U> (deep-moves from the rhs value)
+    template<class U>
+    void assign ( optional<U>&& rhs )
+    {
+      typedef BOOST_DEDUCED_TYPENAME optional<U>::rval_reference_type ref_type;
+      if ( rhs.is_initialized() )
+        m_storage = static_cast<ref_type>(rhs.get());
+      m_initialized = rhs.is_initialized();
+    }
+#endif
+    
+    void assign ( argument_type val )
+    {
+      construct(val);
+    }
+
+    void assign ( none_t ) { destroy(); }
+
+#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    template<class Expr, class ExprPtr>
+    void assign_expr ( Expr&& expr, ExprPtr const* tag )
+    {
+       construct(boost::forward<Expr>(expr),tag);
+    }
+#else
+    template<class Expr>
+    void assign_expr ( Expr const& expr, Expr const* tag )
+    {
+      construct(expr,tag);
+    }
+#endif
+
+#endif
+
+  public :
+
+    // **DEPPRECATED** Destroys the current value, if any, leaving this UNINITIALIZED
+    // No-throw (assuming T::~T() doesn't)
+    void reset() BOOST_NOEXCEPT { destroy(); }
+
+    // **DEPPRECATED** Replaces the current value -if any- with 'val'
+    void reset ( argument_type val ) BOOST_NOEXCEPT { assign(val); }
+
+    // Returns a pointer to the value if this is initialized, otherwise,
+    // returns NULL.
+    // No-throw
+    pointer_const_type get_ptr() const { return m_initialized ? get_ptr_impl() : 0 ; }
+    pointer_type       get_ptr()       { return m_initialized ? get_ptr_impl() : 0 ; }
+
+    bool is_initialized() const { return m_initialized ; }
+
+  protected :
+
+    void construct ( argument_type val )
+     {
+       m_storage = val ;
+       m_initialized = true ;
+     }
+
+
+#if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES) && (!defined BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+    // Constructs in-place
+    // upon exception *this is always uninitialized
+    template<class... Args>
+    void construct ( in_place_init_t, Args&&... args )
+    {
+      m_storage = value_type( boost::forward<Args>(args)... ) ;
+      m_initialized = true ;
+    }
+
+    template<class... Args>
+    void emplace_assign ( Args&&... args )
+    {
+      construct(in_place_init, boost::forward<Args>(args)...);
+    }
+     
+    template<class... Args>
+    explicit tc_optional_base ( in_place_init_t, Args&&... args )
+      :
+      m_initialized(false)
+    {
+      construct(in_place_init, boost::forward<Args>(args)...);
+    }
+    
+    template<class... Args>
+    explicit tc_optional_base ( in_place_init_if_t, bool cond, Args&&... args )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, boost::forward<Args>(args)...);
+    }
+#elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
+    template<class Arg>
+    void construct ( in_place_init_t, Arg&& arg )
+     {
+       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 )
+      :
+      m_initialized(false)
+    {
+      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 )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, boost::forward<Arg>(arg));
+    }
+    
+    explicit tc_optional_base ( in_place_init_if_t, bool cond )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init);
+    }
+
+#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();
+       m_initialized = true ;
+     }
+
+    template<class Arg>
+    void emplace_assign ( const Arg& arg )
+    {
+      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)
+    {
+      construct(in_place_init, arg);
+    }
+
+    template<class Arg>
+    explicit tc_optional_base ( in_place_init_t, Arg& arg )
+      : m_initialized(false)
+    {
+      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)
+    {
+      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)
+    {
+      if ( cond )
+        construct(in_place_init);
+    }
+#endif
+
+#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    // Constructs in-place using the given factory
+    template<class Expr>
+    void construct ( Expr&& factory, in_place_factory_base const* )
+     {
+       boost_optional_detail::construct<value_type>(factory, boost::addressof(m_storage));
+       m_initialized = true ;
+     }
+
+    // Constructs in-place using the given typed factory
+    template<class Expr>
+    void construct ( Expr&& factory, typed_in_place_factory_base const* )
+     {
+       factory.apply(boost::addressof(m_storage)) ;
+       m_initialized = true ;
+     }
+
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr&& factory, in_place_factory_base const* tag )
+     {
+       destroy();
+       construct(factory,tag);
+     }
+
+    // Constructs in-place using the given typed factory
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr&& factory, typed_in_place_factory_base const* tag )
+     {
+       destroy();
+       construct(factory,tag);
+     }
+
+#else
+    // Constructs in-place using the given factory
+    template<class Expr>
+    void construct ( Expr const& factory, in_place_factory_base const* )
+     {
+       boost_optional_detail::construct<value_type>(factory, m_storage.address());
+       m_initialized = true ;
+     }
+
+    // Constructs in-place using the given typed factory
+    template<class Expr>
+    void construct ( Expr const& factory, typed_in_place_factory_base const* )
+     {
+       factory.apply(boost::addressof(m_storage)) ;
+       m_initialized = true ;
+     }
+
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr const& factory, in_place_factory_base const* tag )
+     {
+       destroy();
+       construct(factory,tag);
+     }
+
+    // Constructs in-place using the given typed factory
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr const& factory, typed_in_place_factory_base const* tag )
+     {
+       destroy();
+       construct(factory,tag);
+     }
+#endif
+
+#endif
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    // Constructs using any expression implicitly convertible to the single argument
+    // of a one-argument T constructor.
+    // Converting constructions of optional<T> from optional<U> uses this function with
+    // 'Expr' being of type 'U' and relying on a converting constructor of T from U.
+    template<class Expr>
+    void construct ( Expr&& expr, void const* )
+    {
+      m_storage = value_type(boost::forward<Expr>(expr)) ;
+      m_initialized = true ;
+    }
+
+    // Assigns using a form any expression implicitly convertible to the single argument
+    // of a T's assignment operator.
+    // Converting assignments of optional<T> from optional<U> uses this function with
+    // 'Expr' being of type 'U' and relying on a converting assignment of T from U.
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr&& expr, void const* )
+    {
+      assign_value( boost::forward<Expr>(expr) );
+    }
+#else
+    // Constructs using any expression implicitly convertible to the single argument
+    // of a one-argument T constructor.
+    // Converting constructions of optional<T> from optional<U> uses this function with
+    // 'Expr' being of type 'U' and relying on a converting constructor of T from U.
+    template<class Expr>
+    void construct ( Expr const& expr, void const* )
+     {
+       m_storage = value_type(expr) ;
+       m_initialized = true ;
+     }
+
+    // Assigns using a form any expression implicitly convertible to the single argument
+    // of a T's assignment operator.
+    // Converting assignments of optional<T> from optional<U> uses this function with
+    // 'Expr' being of type 'U' and relying on a converting assignment of T from U.
+    template<class Expr>
+    void assign_expr_to_initialized ( Expr const& expr, void const* )
+     {
+       assign_value(expr);
+     }
+
+#endif
+
+#ifdef BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
+    // BCB5.64 (and probably lower versions) workaround.
+    //   The in-place factories are supported by means of catch-all constructors
+    //   and assignment operators (the functions are parameterized in terms of
+    //   an arbitrary 'Expr' type)
+    //   This compiler incorrectly resolves the overload set and sinks optional<T> and optional<U>
+    //   to the 'Expr'-taking functions even though explicit overloads are present for them.
+    //   Thus, the following overload is needed to properly handle the case when the 'lhs'
+    //   is another optional.
+    //
+    // For VC<=70 compilers this workaround dosen't work becasue the comnpiler issues and error
+    // instead of choosing the wrong overload
+    //
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    // Notice that 'Expr' will be optional<T> or optional<U> (but not tc_optional_base<..>)
+    template<class Expr>
+    void construct ( Expr&& expr, optional_tag const* )
+     {
+       if ( expr.is_initialized() )
+       {
+         // An exception can be thrown here.
+         // It it happens, THIS will be left uninitialized.
+         m_storage = value_type(boost::move(expr.get())) ;
+         m_initialized = true ;
+       }
+     }
+#else
+    // Notice that 'Expr' will be optional<T> or optional<U> (but not tc_optional_base<..>)
+    template<class Expr>
+    void construct ( Expr const& expr, optional_tag const* )
+     {
+       if ( expr.is_initialized() )
+       {
+         // An exception can be thrown here.
+         // It it happens, THIS will be left uninitialized.
+         m_storage = value_type(expr.get()) ;
+         m_initialized = true ;
+       }
+     }
+#endif
+#endif // defined BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
+
+    void assign_value ( argument_type val ) { m_storage = val; }
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    void assign_value ( rval_reference_type val ) { m_storage = static_cast<rval_reference_type>(val); }
+#endif
+
+    void destroy()
+    {
+      m_initialized = false;
+    }
+
+    reference_const_type get_impl() const { return m_storage ; }
+    reference_type       get_impl()       { return m_storage ; }
+
+    pointer_const_type get_ptr_impl() const { return boost::addressof(m_storage); }
+    pointer_type       get_ptr_impl()       { return boost::addressof(m_storage); }
+
+  private :
+
+    bool m_initialized ;
+    T    m_storage ;
+} ;

include/boost/optional/optional.hpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
-// Copyright (C) 2014, 2015 Andrzej Krzemienski.
+// Copyright (C) 2014 - 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
@@ -20,6 +20,10 @@
 #include <new>
 #include <iosfwd>
 
+#ifdef BOOST_OPTIONAL_DETAIL_USE_STD_TYPE_TRAITS
+#  include <type_traits>
+#endif
+
 #include <boost/assert.hpp>
 #include <boost/core/addressof.hpp>
 #include <boost/core/enable_if.hpp>
@@ -37,12 +41,15 @@
 #include <boost/type_traits/remove_reference.hpp>
 #include <boost/type_traits/decay.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_lvalue_reference.hpp>
 #include <boost/type_traits/is_nothrow_move_assignable.hpp>
 #include <boost/type_traits/is_nothrow_move_constructible.hpp>
 #include <boost/type_traits/is_rvalue_reference.hpp>
 #include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/is_volatile.hpp>
+#include <boost/type_traits/is_scalar.hpp>
 #include <boost/move/utility.hpp>
 #include <boost/none.hpp>
 #include <boost/utility/compare_pointees.hpp>
@@ -56,6 +63,31 @@
 #include <boost/optional/detail/old_optional_implementation.hpp>
 #else
 namespace boost {
+  
+namespace optional_ns {
+  
+// a tag for in-place initialization of contained value
+struct in_place_init_t
+{
+  struct init_tag{};
+  explicit in_place_init_t(init_tag){}
+};            
+const in_place_init_t in_place_init ((in_place_init_t::init_tag()));
+
+// a tag for conditional in-place initialization of contained value
+struct in_place_init_if_t
+{
+  struct init_tag{};
+  explicit in_place_init_if_t(init_tag){}
+};
+const in_place_init_if_t in_place_init_if ((in_place_init_if_t::init_tag()));
+  
+} // namespace optional_ns
+
+using optional_ns::in_place_init_t;
+using optional_ns::in_place_init;
+using optional_ns::in_place_init_if_t;
+using optional_ns::in_place_init_if;
 
 namespace optional_detail {
 
@@ -117,7 +149,7 @@ class optional_base : public optional_tag
     }
 #endif
 
-    // Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialzed optional<T>.
+    // Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional<T>.
     // Can throw if T::T(T const&) does
     optional_base ( bool cond, argument_type val )
       :
@@ -127,6 +159,18 @@ class optional_base : public optional_tag
         construct(val);
     }
 
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    // Creates an optional<T> initialized with 'move(val)' IFF cond is true, otherwise creates an uninitialized optional<T>.
+    // Can throw if T::T(T &&) does
+    optional_base ( bool cond, rval_reference_type val )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(boost::move(val));
+    }
+#endif
+
     // Creates a deep copy of another optional<T>
     // Can throw if T::T(T const&) does
     optional_base ( optional_base const& rhs )
@@ -141,6 +185,7 @@ class optional_base : public optional_tag
     // Creates a deep move of another optional<T>
     // Can throw if T::T(T&&) does
     optional_base ( optional_base&& rhs )
+    BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
       :
       m_initialized(false)
     {
@@ -173,6 +218,20 @@ class optional_base : public optional_tag
 
 #endif
 
+    optional_base& operator= ( optional_base const& rhs )
+    {
+      this->assign(rhs);
+      return *this;
+    }
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    optional_base& operator= ( optional_base && rhs )
+    BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
+    {
+      this->assign(static_cast<optional_base&&>(rhs));
+      return *this;
+    }
+#endif
 
     // No-throw (assuming T::~T() doesn't)
     ~optional_base() { destroy() ; }
@@ -338,51 +397,179 @@ class optional_base : public optional_tag
 #if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES) && (!defined BOOST_NO_CXX11_VARIADIC_TEMPLATES)
     // Constructs in-place
     // upon exception *this is always uninitialized
+    template<class... Args>
+    void construct ( in_place_init_t, Args&&... args )
+    {
+      ::new (m_storage.address()) value_type( boost::forward<Args>(args)... ) ;
+      m_initialized = true ;
+    }
+
     template<class... Args>
     void emplace_assign ( Args&&... args )
-     {
-       destroy();
-       ::new (m_storage.address()) value_type( boost::forward<Args>(args)... );
-       m_initialized = true ;
-     }
+    {
+      destroy();
+      construct(in_place_init, boost::forward<Args>(args)...);
+    }
+     
+    template<class... Args>
+    explicit optional_base ( in_place_init_t, Args&&... args )
+      :
+      m_initialized(false)
+    {
+      construct(in_place_init, boost::forward<Args>(args)...);
+    }
+    
+    template<class... Args>
+    explicit optional_base ( in_place_init_if_t, bool cond, Args&&... args )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, boost::forward<Args>(args)...);
+    }
 #elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
     template<class Arg>
-    void emplace_assign ( Arg&& arg )
+    void construct ( in_place_init_t, Arg&& arg )
      {
-       destroy();
        ::new (m_storage.address()) value_type( boost::forward<Arg>(arg) );
        m_initialized = true ;
      }
      
-    void emplace_assign ()
+    void construct ( in_place_init_t )
      {
-       destroy();
        ::new (m_storage.address()) value_type();
        m_initialized = true ;
      }
-#else
+     
     template<class Arg>
-    void emplace_assign ( const Arg& arg )
+    void emplace_assign ( Arg&& arg )
      {
        destroy();
+       construct(in_place_init, boost::forward<Arg>(arg)) ;
+     }
+     
+    void emplace_assign ()
+     {
+       destroy();
+       construct(in_place_init) ;
+     }
+     
+    template<class Arg>
+    explicit optional_base ( in_place_init_t, Arg&& arg )
+      :
+      m_initialized(false)
+    {
+      construct(in_place_init, boost::forward<Arg>(arg));
+    }
+    
+    explicit optional_base ( in_place_init_t )
+      :
+      m_initialized(false)
+    {
+      construct(in_place_init);
+    }
+    
+    template<class Arg>
+    explicit optional_base ( in_place_init_if_t, bool cond, Arg&& arg )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, boost::forward<Arg>(arg));
+    }
+    
+    explicit optional_base ( in_place_init_if_t, bool cond )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init);
+    }
+
+#else
+     
+    template<class Arg>
+    void construct ( in_place_init_t, const Arg& arg )
+     {
        ::new (m_storage.address()) value_type( arg );
        m_initialized = true ;
      }
      
+    template<class Arg>
+    void construct ( in_place_init_t, Arg& arg )
+     {
+       ::new (m_storage.address()) value_type( arg );
+       m_initialized = true ;
+     }
+     
+    void construct ( in_place_init_t )
+     {
+       ::new (m_storage.address()) value_type();
+       m_initialized = true ;
+     }
+
+    template<class Arg>
+    void emplace_assign ( const Arg& arg )
+    {
+      destroy();
+      construct(in_place_init, arg);
+    }
+     
     template<class Arg>
     void emplace_assign ( Arg& arg )
-     {
-       destroy();
-       ::new (m_storage.address()) value_type( arg );
-       m_initialized = true ;
-     }
+    {
+      destroy();
+      construct(in_place_init, arg);
+    }
      
     void emplace_assign ()
-     {
-       destroy();
-       ::new (m_storage.address()) value_type();
-       m_initialized = true ;
-     }
+    {
+      destroy();
+      construct(in_place_init);
+    }
+    
+    template<class Arg>
+    explicit optional_base ( in_place_init_t, const Arg& arg )
+      : m_initialized(false)
+    {
+      construct(in_place_init, arg);
+    }
+
+    template<class Arg>
+    explicit optional_base ( in_place_init_t, Arg& arg )
+      : m_initialized(false)
+    {
+      construct(in_place_init, arg);
+    }
+    
+    explicit optional_base ( in_place_init_t )
+      : m_initialized(false)
+    {
+      construct(in_place_init);
+    }
+    
+    template<class Arg>
+    explicit optional_base ( in_place_init_if_t, bool cond, const Arg& arg )
+      : m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, arg);
+    }
+    
+    template<class Arg>
+    explicit optional_base ( in_place_init_if_t, bool cond, Arg& arg )
+      : m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init, arg);
+    } 
+    
+    explicit optional_base ( in_place_init_if_t, bool cond )
+      : m_initialized(false)
+    {
+      if ( cond )
+        construct(in_place_init);
+    }
 #endif
 
 #ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
@@ -560,7 +747,7 @@ class optional_base : public optional_tag
 
   private :
 
-#if BOOST_WORKAROUND(BOOST_MSVC, <= 1600)
+#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1900))
     void destroy_impl ( ) { m_storage.ptr_ref()->~T() ; m_initialized = false ; }
 #else
     void destroy_impl ( ) { m_storage.ref().T::~T() ; m_initialized = false ; }
@@ -570,34 +757,44 @@ class optional_base : public optional_tag
     storage_type m_storage ;
 } ;
 
+
+
+#include <boost/optional/detail/optional_trivially_copyable_base.hpp>
+
 // definition of metafunciton is_optional_val_init_candidate
 template <typename U>
 struct is_optional_related
   : 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, none_t>::value
+                     || boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<U>::type, in_place_init_t>::value
+                     || boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<U>::type, in_place_init_if_t>::value,
     boost::true_type, boost::false_type>::type
 {};
 
-#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500) && !defined(__SUNPRO_CC)
-  // this condition is a copy paste from is_constructible.hpp
-  // I also disable SUNPRO, as it seems not to support type_traits correctly
+#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_constructible<T, U&&>::value && !boost::is_same<T, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value)
                       , boost::true_type, boost::false_type>::type
 {};
 
+template <typename T, typename U>
+struct is_optional_constructible : boost::is_constructible<T, U>
+{};
+
 #else
 
-#define BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT
-
 template <typename, typename>
 struct is_convertible_to_T_or_factory : boost::true_type
 {};
 
+template <typename T, typename U>
+struct is_optional_constructible : boost::true_type
+{};
+
 #endif // is_convertible condition
 
 template <typename T, typename U>
@@ -605,13 +802,34 @@ struct is_optional_val_init_candidate
   : boost::conditional< !is_optional_related<U>::value && is_convertible_to_T_or_factory<T, U>::value
                       , boost::true_type, boost::false_type>::type
 {};
-    
+
 } // namespace optional_detail
 
+namespace optional_config {
+
+template <typename T>
+struct optional_uses_direct_storage_for
+  : boost::conditional<(boost::is_scalar<T>::value && !boost::is_const<T>::value && !boost::is_volatile<T>::value)
+                      , boost::true_type, boost::false_type>::type
+{};
+
+} // namespace optional_config
+
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DIRECT_STORAGE_SPEC
+#  define BOOST_OPTIONAL_BASE_TYPE(T) boost::conditional< optional_config::optional_uses_direct_storage_for<T>::value, \
+                                      optional_detail::tc_optional_base<T>, \
+                                      optional_detail::optional_base<T> \
+                                      >::type
+#else
+#  define BOOST_OPTIONAL_BASE_TYPE(T) optional_detail::optional_base<T>
+#endif
+
 template<class T>
-class optional : public optional_detail::optional_base<T>
+class optional
+  : public BOOST_OPTIONAL_BASE_TYPE(T)
 {
-    typedef optional_detail::optional_base<T> base ;
+    typedef typename BOOST_OPTIONAL_BASE_TYPE(T) base ;
 
   public :
 
@@ -651,16 +869,27 @@ class optional : public optional_detail::optional_base<T>
     // Can throw if T::T(T const&) does
     optional ( bool cond, argument_type val ) : base(cond,val) {}
 
+#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+    /// Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional.
+    // Can throw if T::T(T &&) does
+    optional ( bool cond, rval_reference_type val ) : base( cond, boost::forward<T>(val) ) 
+      {}
+#endif
+
     // NOTE: MSVC needs templated versions first
 
     // Creates a deep copy of another convertible optional<U>
     // Requires a valid conversion from U to T.
     // Can throw if T::T(U const&) does
     template<class U>
-    explicit optional ( optional<U> const& rhs )
+    explicit optional ( optional<U> const& rhs
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+                        ,BOOST_DEDUCED_TYPENAME boost::enable_if< optional_detail::is_optional_constructible<T, U const&>, bool>::type = true
+#endif
+                      )
       :
       base()
-    {
+    {      
       if ( rhs.is_initialized() )
         this->construct(rhs.get());
     }
@@ -670,7 +899,11 @@ class optional : public optional_detail::optional_base<T>
     // Requires a valid conversion from U to T.
     // Can throw if T::T(U&&) does
     template<class U>
-    explicit optional ( optional<U> && rhs )
+    explicit optional ( optional<U> && rhs
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+                        ,BOOST_DEDUCED_TYPENAME boost::enable_if< optional_detail::is_optional_constructible<T, U>, bool>::type = true
+#endif
+                      )
       :
       base()
     {
@@ -694,7 +927,7 @@ class optional : public optional_detail::optional_base<T>
 
   template<class Expr>
   explicit optional ( Expr&& expr, 
-                      BOOST_DEDUCED_TYPENAME boost::enable_if< optional_detail::is_optional_val_init_candidate<T, Expr> >::type* = 0 
+                      BOOST_DEDUCED_TYPENAME boost::enable_if< optional_detail::is_optional_val_init_candidate<T, Expr>, bool>::type = true 
   ) 
     : base(boost::forward<Expr>(expr),boost::addressof(expr)) 
     {}
@@ -707,15 +940,24 @@ class optional : public optional_detail::optional_base<T>
 
     // Creates a deep copy of another optional<T>
     // Can throw if T::T(T const&) does
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+    optional ( optional const& ) = default;
+#else
     optional ( optional const& rhs ) : base( static_cast<base const&>(rhs) ) {}
+#endif
 
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
-	// Creates a deep move of another optional<T>
-	// Can throw if T::T(T&&) does
-	optional ( optional && rhs ) 
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
-	  : base( boost::move(rhs) ) 
-	{}
+    // Creates a deep move of another optional<T>
+    // Can throw if T::T(T&&) does
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+    optional ( optional && rhs ) = default;
+#else
+    optional ( optional && rhs )
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
+      : base( boost::move(rhs) )
+    {}
+#endif
 
 #endif
 
@@ -724,7 +966,7 @@ class optional : public optional_detail::optional_base<T>
     ~optional() {}
 #endif
 
-	
+
 #if !defined(BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT) && !defined(BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION)
     // Assigns from an expression. See corresponding constructor.
     // Basic Guarantee: If the resolved T ctor throws, this is left UNINITIALIZED
@@ -773,21 +1015,43 @@ class optional : public optional_detail::optional_base<T>
     // Assigns from another optional<T> (deep-copies the rhs value)
     // Basic Guarantee: If T::T( T const& ) throws, this is left UNINITIALIZED
     //  (NOTE: On BCB, this operator is not actually called and left is left UNMODIFIED in case of a throw)
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+    optional& operator= ( optional const& rhs ) = default;
+#else
     optional& operator= ( optional const& rhs )
       {
         this->assign( static_cast<base const&>(rhs) ) ;
         return *this ;
       }
+#endif
 
 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
     // Assigns from another optional<T> (deep-moves the rhs value)
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+    optional& operator= ( optional && ) = default;
+#else
     optional& operator= ( optional && rhs ) 
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
       {
         this->assign( static_cast<base &&>(rhs) ) ;
         return *this ;
       }
-#endif
+#endif      
+      
+#endif // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+
+#ifndef BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
+
+    // Assigns from a T (deep-moves/copies the rhs value)
+    template <typename T_>
+    BOOST_DEDUCED_TYPENAME boost::enable_if<boost::is_same<T, BOOST_DEDUCED_TYPENAME boost::decay<T_>::type>, optional&>::type
+    operator= ( T_&& val )
+      {
+        this->assign( boost::forward<T_>(val) ) ;
+        return *this ;
+      }
+      
+#else
 
     // Assigns from a T (deep-copies the rhs value)
     // Basic Guarantee: If T::( T const& ) throws, this is left UNINITIALIZED
@@ -796,7 +1060,7 @@ class optional : public optional_detail::optional_base<T>
         this->assign( val ) ;
         return *this ;
       }
-
+      
 #ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
     // Assigns from a T (deep-moves the rhs value)
     optional& operator= ( rval_reference_type val )
@@ -805,7 +1069,9 @@ class optional : public optional_detail::optional_base<T>
         return *this ;
       }
 #endif
-
+      
+#endif // BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
+      
     // Assigns from a "none"
     // Which destroys the current value, if any, leaving this UNINITIALIZED
     // No-throw (assuming T::~T() doesn't)
@@ -820,9 +1086,20 @@ class optional : public optional_detail::optional_base<T>
     // upon exception *this is always uninitialized
     template<class... Args>
     void emplace ( Args&&... args )
-     {
-       this->emplace_assign( boost::forward<Args>(args)... );
-     }
+    {
+      this->emplace_assign( boost::forward<Args>(args)... );
+    }
+     
+    template<class... Args>
+    explicit optional ( in_place_init_t, Args&&... args )
+    : base( in_place_init, boost::forward<Args>(args)... )
+    {}
+    
+    template<class... Args>
+    explicit optional ( in_place_init_if_t, bool cond, Args&&... args )
+    : base( in_place_init_if, cond, boost::forward<Args>(args)... )
+    {}
+    
 #elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
     template<class Arg>
     void emplace ( Arg&& arg )
@@ -834,6 +1111,24 @@ class optional : public optional_detail::optional_base<T>
      {
        this->emplace_assign();
      }
+     
+    template<class Args>
+    explicit optional ( in_place_init_t, Args&& args )
+    : base( in_place_init, boost::forward<Args>(args) )
+    {}
+
+    explicit optional ( in_place_init_t )
+    : base( in_place_init )
+    {}
+    
+    template<class Args>
+    explicit optional ( in_place_init_if_t, bool cond, Args&& args )
+    : base( in_place_init_if, cond, boost::forward<Args>(args) )
+    {}
+    
+    explicit optional ( in_place_init_if_t, bool cond )
+    : base( in_place_init_if, cond )
+    {}
 #else
     template<class Arg>
     void emplace ( const Arg& arg )
@@ -851,10 +1146,38 @@ class optional : public optional_detail::optional_base<T>
      {
        this->emplace_assign();
      }
+     
+    template<class Arg>
+    explicit optional ( in_place_init_t, const Arg& arg )
+    : base( in_place_init, arg )
+    {}
+    
+    template<class Arg>
+    explicit optional ( in_place_init_t, Arg& arg )
+    : base( in_place_init, arg )
+    {}
+
+    explicit optional ( in_place_init_t )
+    : base( in_place_init )
+    {}
+    
+    template<class Arg>
+    explicit optional ( in_place_init_if_t, bool cond, const Arg& arg )
+    : base( in_place_init_if, cond, arg )
+    {}
+    
+    template<class Arg>
+    explicit optional ( in_place_init_if_t, bool cond, Arg& arg )
+    : base( in_place_init_if, cond, arg )
+    {} 
+    
+    explicit optional ( in_place_init_if_t, bool cond )
+    : base( in_place_init_if, cond )
+    {}
 #endif
 
     void swap( optional & arg )
-	  BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
+      BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
       {
         // allow for Koenig lookup
         boost::swap(*this, arg);
@@ -1037,6 +1360,25 @@ class optional<T&&>
 
 namespace boost {
 
+#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+
+template<class T>
+inline
+optional<BOOST_DEDUCED_TYPENAME boost::decay<T>::type> make_optional ( T && v  )
+{
+  return optional<BOOST_DEDUCED_TYPENAME boost::decay<T>::type>(boost::forward<T>(v));
+}
+
+// Returns optional<T>(cond,v)
+template<class T>
+inline
+optional<BOOST_DEDUCED_TYPENAME boost::decay<T>::type> make_optional ( bool cond, T && v )
+{
+  return optional<BOOST_DEDUCED_TYPENAME boost::decay<T>::type>(cond,boost::forward<T>(v));
+}
+
+#else
+
 // Returns optional<T>(v)
 template<class T>
 inline
@@ -1053,6 +1395,8 @@ optional<T> make_optional ( bool cond, T const& v )
   return optional<T>(cond,v);
 }
 
+#endif // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+
 // Returns a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED.
 // No-throw
 template<class T>

test/Jamfile.v2

@@ -1,7 +1,7 @@
 # Boost.Optional Library test Jamfile
 #
 # Copyright (C) 2003, Fernando Luis Cacciola Carballal.
-# Copyright (C) 2014, 2015 Andrzej Krzemienski
+# Copyright (C) 2014 - 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
@@ -20,6 +20,9 @@ import testing ;
     [ run optional_test.cpp ]
     [ run optional_test_swap.cpp ]
     [ run optional_test_conversions_from_U.cpp ]
+    [ run optional_test_convert_from_T.cpp ]
+    [ run optional_test_empty_braces.cpp ]
+    [ run optional_test_make_optional.cpp ]
     [ run optional_test_tie.cpp ]
     [ run optional_test_ref_assign_portable_minimum.cpp ]
     [ run optional_test_ref_assign_mutable_int.cpp ]
@@ -40,7 +43,9 @@ import testing ;
     [ run optional_test_emplace.cpp ]
     [ run optional_test_minimum_requirements.cpp ]
     [ run optional_test_msvc_bug_workaround.cpp ]
-    [ compile optional_test_sfinae_friendly_value_ctor.cpp ]
+    [ run optional_test_member_T.cpp ]
+    [ run optional_test_tc_base.cpp ]
+    [ compile optional_test_sfinae_friendly_ctor.cpp ]
     [ compile-fail optional_test_ref_convert_assign_const_int_prevented.cpp ]
     [ compile-fail optional_test_fail1.cpp ]
     [ compile-fail optional_test_fail3a.cpp ]
@@ -63,6 +68,9 @@ import testing ;
     [ compile-fail optional_test_fail_io_without_io.cpp ]
     [ compile-fail optional_test_fail_none_io_without_io.cpp ]
     [ compile-fail optional_test_fail_convert_assign_of_enums.cpp ]
+    [ run optional_test_static_properties.cpp ]
+    [ compile optional_test_maybe_uninitialized_warning.cpp ]
+    [ compile optional_test_deleted_default_ctor.cpp ]
     [ run optional_xconfig_NO_PROPER_ASSIGN_FROM_CONST_INT_pass.cpp ]
     [ run-fail optional_xconfig_NO_PROPER_ASSIGN_FROM_CONST_INT_fail.cpp ]
     [ run optional_xconfig_NO_PROPER_CONVERT_FROM_CONST_INT_pass.cpp ]

test/optional_test_common.cpp

@@ -152,21 +152,21 @@ bool X::pending_assign  = false ;
 bool X::throw_on_copy   = false ;
 bool X::throw_on_assign = false ;
 
-inline void set_pending_copy           ( X const* x ) { X::pending_copy  = true  ; }
-inline void set_pending_dtor           ( X const* x ) { X::pending_dtor  = true  ; }
-inline void set_pending_assign         ( X const* x ) { X::pending_assign = true  ; }
-inline void set_throw_on_copy          ( X const* x ) { X::throw_on_copy = true  ; }
-inline void set_throw_on_assign        ( X const* x ) { X::throw_on_assign = true  ; }
-inline void reset_throw_on_copy        ( X const* x ) { X::throw_on_copy = false ; }
-inline void reset_throw_on_assign      ( X const* x ) { X::throw_on_assign = false ; }
-inline void check_is_pending_copy      ( X const* x ) { BOOST_TEST( X::pending_copy ) ; }
-inline void check_is_pending_dtor      ( X const* x ) { BOOST_TEST( X::pending_dtor ) ; }
-inline void check_is_pending_assign    ( X const* x ) { BOOST_TEST( X::pending_assign ) ; }
-inline void check_is_not_pending_copy  ( X const* x ) { BOOST_TEST( !X::pending_copy ) ; }
-inline void check_is_not_pending_dtor  ( X const* x ) { BOOST_TEST( !X::pending_dtor ) ; }
-inline void check_is_not_pending_assign( X const* x ) { BOOST_TEST( !X::pending_assign ) ; }
-inline void check_instance_count       ( int c, X const* x ) { BOOST_TEST( X::count == c ) ; }
-inline int  get_instance_count         ( X const* x ) { return X::count ; }
+inline void set_pending_copy           ( X const* ) { X::pending_copy  = true  ; }
+inline void set_pending_dtor           ( X const* ) { X::pending_dtor  = true  ; }
+inline void set_pending_assign         ( X const* ) { X::pending_assign = true  ; }
+inline void set_throw_on_copy          ( X const* ) { X::throw_on_copy = true  ; }
+inline void set_throw_on_assign        ( X const* ) { X::throw_on_assign = true  ; }
+inline void reset_throw_on_copy        ( X const* ) { X::throw_on_copy = false ; }
+inline void reset_throw_on_assign      ( X const* ) { X::throw_on_assign = false ; }
+inline void check_is_pending_copy      ( X const* ) { BOOST_TEST( X::pending_copy ) ; }
+inline void check_is_pending_dtor      ( X const* ) { BOOST_TEST( X::pending_dtor ) ; }
+inline void check_is_pending_assign    ( X const* ) { BOOST_TEST( X::pending_assign ) ; }
+inline void check_is_not_pending_copy  ( X const* ) { BOOST_TEST( !X::pending_copy ) ; }
+inline void check_is_not_pending_dtor  ( X const* ) { BOOST_TEST( !X::pending_dtor ) ; }
+inline void check_is_not_pending_assign( X const* ) { BOOST_TEST( !X::pending_assign ) ; }
+inline void check_instance_count       ( int c, X const* ) { BOOST_TEST( X::count == c ) ; }
+inline int  get_instance_count         ( X const* ) { return X::count ; }
 
 inline void set_pending_copy           (...) {}
 inline void set_pending_dtor           (...) {}

test/optional_test_convert_from_T.cpp

@@ -0,0 +1,70 @@
+// 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"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+#include "boost/none.hpp"
+
+//#ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
+
+using boost::optional;
+using boost::none;
+
+template <typename U>
+struct superconv
+{
+  #ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+  template <typename T>
+    superconv(T&&) { BOOST_STATIC_ASSERT(sizeof(T) == 0); }
+  #else
+  template <typename T>
+    superconv(const T&) { BOOST_STATIC_ASSERT(sizeof(T) == 0); }
+  template <typename T>
+    superconv(      T&) { BOOST_STATIC_ASSERT(sizeof(T) == 0); }
+  #endif
+  
+  superconv() {}
+};
+
+void test_optional_of_superconverting_T() // compile-time test
+{
+#ifndef BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT
+  superconv<optional<int> > s;
+   superconv<optional<int> > & rs = s;
+  optional<superconv<optional<int> > > os = rs;
+#endif
+}
+
+void test_optional_optional_T()
+{
+  optional<int> oi1 (1), oiN;
+  optional< optional<int> > ooi1 (oi1), ooiN(oiN);
+  
+  BOOST_TEST(ooi1);
+  BOOST_TEST(*ooi1);
+  BOOST_TEST_EQ(**ooi1, 1);
+  
+  BOOST_TEST(ooiN);
+  BOOST_TEST(!*ooiN);
+}  
+
+int main()
+{
+    test_optional_optional_T();
+    test_optional_of_superconverting_T();
+    
+    return boost::report_errors();
+}

test/optional_test_deleted_default_ctor.cpp

@@ -0,0 +1,44 @@
+// Copyright 2017 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config.hpp>
+
+#if defined(BOOST_NO_CXX11_DELETED_FUNCTIONS)
+
+int main()
+{
+}
+
+#else
+
+#include <boost/optional.hpp>
+#include <utility>
+
+class basic_multi_buffer;
+
+class const_buffers_type
+{
+    basic_multi_buffer const* b_;
+
+    friend class basic_multi_buffer;
+
+    explicit
+    const_buffers_type(basic_multi_buffer const& b);
+
+public:
+
+    const_buffers_type() = delete;
+    const_buffers_type(const_buffers_type const&) = default;
+    const_buffers_type& operator=(const_buffers_type const&) = default;
+};
+
+int main()
+{
+    boost::optional< std::pair<const_buffers_type, int> > opt, opt2;
+    opt = opt2;
+}
+
+#endif

test/optional_test_emplace.cpp

@@ -23,6 +23,8 @@
 
 using boost::optional;
 using boost::none;
+using boost::in_place_init;
+using boost::in_place_init_if;
 
 #if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES) && (!defined BOOST_NO_CXX11_VARIADIC_TEMPLATES)
 
@@ -87,6 +89,109 @@ void test_emplace()
     BOOST_TEST(7 == o->which_ctor);
 }
 
+void test_in_place_ctor()
+{
+    int i = 0;
+    double d = 0.0;
+    const std::string cs;
+    std::string ms;
+        
+  {
+    optional<Guard> o (in_place_init);
+    BOOST_TEST(o);
+    BOOST_TEST(0 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, i, 2.0);
+    BOOST_TEST(o);
+    BOOST_TEST(1 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, 1, d);
+    BOOST_TEST(o);
+    BOOST_TEST(2 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, 1, 2.0);
+    BOOST_TEST(o);
+    BOOST_TEST(3 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, i, d);
+    BOOST_TEST(o);
+    BOOST_TEST(4 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, cs);
+    BOOST_TEST(o);
+    BOOST_TEST(5 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, ms);
+    BOOST_TEST(o);
+    BOOST_TEST(6 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init, std::string());
+    BOOST_TEST(o);
+    BOOST_TEST(7 == o->which_ctor);
+  }
+}
+
+void test_in_place_if_ctor()
+{
+    int i = 0;
+    double d = 0.0;
+    const std::string cs;
+    std::string ms;
+        
+  {
+    optional<Guard> o (in_place_init_if, true);
+    BOOST_TEST(o);
+    BOOST_TEST(0 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, i, 2.0);
+    BOOST_TEST(o);
+    BOOST_TEST(1 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, 1, d);
+    BOOST_TEST(o);
+    BOOST_TEST(2 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, 1, 2.0);
+    BOOST_TEST(o);
+    BOOST_TEST(3 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, i, d);
+    BOOST_TEST(o);
+    BOOST_TEST(4 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, cs);
+    BOOST_TEST(o);
+    BOOST_TEST(5 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, ms);
+    BOOST_TEST(o);
+    BOOST_TEST(6 == o->which_ctor);
+  }
+  {  
+    optional<Guard> o (in_place_init_if, true, std::string());
+    BOOST_TEST(o);
+    BOOST_TEST(7 == o->which_ctor);
+  }
+  
+  {
+    optional<Guard> o (in_place_init_if, false, 1, 2.0);
+    BOOST_TEST(!o);
+  }
+}
+
 
 #endif
 
@@ -112,6 +217,24 @@ void test_no_moves_on_emplacement()
         BOOST_TEST(false);
     }
 }
+
+void test_no_moves_on_in_place_ctor()
+{
+    try {
+        optional<ThrowOnMove> o (in_place_init, 1);
+        BOOST_TEST(o);
+        
+        optional<ThrowOnMove> p (in_place_init_if, true, 1);
+        BOOST_TEST(p);
+        
+        optional<ThrowOnMove> q (in_place_init_if, false, 1);
+        BOOST_TEST(!q);
+    } 
+    catch (...) {
+        BOOST_TEST(false);
+    }
+}
+
 #endif
 
 struct Thrower
@@ -158,6 +281,7 @@ void test_no_assignment_on_emplacement()
 }
 
 namespace no_rvalue_refs {
+
 class Guard
 {
 public:
@@ -188,19 +312,78 @@ void test_emplace()
     BOOST_TEST(o);
     BOOST_TEST(6 == o->which_ctor);
 }
-} 
+
+void test_in_place_ctor()
+{
+  const std::string cs;
+  std::string ms;
+  
+  {
+    optional<Guard> o (in_place_init);
+    BOOST_TEST(o);
+    BOOST_TEST(0 == o->which_ctor);
+  }
+  {
+    optional<Guard> o (in_place_init, cs);
+    BOOST_TEST(o);
+    BOOST_TEST(5 == o->which_ctor);
+  }
+  {
+    optional<Guard> o (in_place_init, ms);
+    BOOST_TEST(o);
+    BOOST_TEST(6 == o->which_ctor);
+  }
+}
+
+void test_in_place_if_ctor()
+{
+  const std::string cs;
+  std::string ms;
+  
+  {
+    optional<Guard> n (in_place_init_if, false);
+    BOOST_TEST(!n);
+    
+    optional<Guard> o (in_place_init_if, true);
+    BOOST_TEST(o);
+    BOOST_TEST(0 == o->which_ctor);
+  }
+  {
+    optional<Guard> n (in_place_init_if, false, cs);
+    BOOST_TEST(!n);
+    
+    optional<Guard> o (in_place_init_if, true, cs);
+    BOOST_TEST(o);
+    BOOST_TEST(5 == o->which_ctor);
+  }
+  {
+    optional<Guard> n (in_place_init_if, false, ms);
+    BOOST_TEST(!n);
+    
+    optional<Guard> o (in_place_init_if, true, ms);
+    BOOST_TEST(o);
+    BOOST_TEST(6 == o->which_ctor);
+  }
+}
+
+} // namespace no_rvalue_ref
 
 int main()
 {
 #if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES) && (!defined BOOST_NO_CXX11_VARIADIC_TEMPLATES)
     test_emplace();
+    test_in_place_ctor();
+    test_in_place_if_ctor();
 #endif
 #if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
     test_no_moves_on_emplacement();
+    test_no_moves_on_in_place_ctor();
 #endif
     test_clear_on_throw();
     test_no_assignment_on_emplacement();
     no_rvalue_refs::test_emplace();
+    no_rvalue_refs::test_in_place_ctor();
+    no_rvalue_refs::test_in_place_if_ctor();
   
     return boost::report_errors();
 }

test/optional_test_empty_braces.cpp

@@ -0,0 +1,57 @@
+// Copyright (C) 2016 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"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+
+//#ifndef BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT
+//#ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
+
+using boost::optional;
+
+struct Value
+{
+  explicit Value(int) {}
+};
+
+#ifndef BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
+template <typename T>
+void test_brace_init()
+{
+  optional<T> o = {};
+  BOOST_TEST(!o);
+}
+
+template <typename T>
+void test_brace_assign()
+{
+  optional<T> o;
+  o = {};
+  BOOST_TEST(!o);
+} 
+#endif
+
+int main()
+{
+#ifndef BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
+  test_brace_init<int>();
+  test_brace_init<Value>();
+  test_brace_assign<int>();
+  test_brace_assign<Value>();
+#endif
+
+  return boost::report_errors();
+}

test/optional_test_experimental_traits.cpp

@@ -0,0 +1,152 @@
+// 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/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+#include "boost/core/lightweight_test_trait.hpp"
+#include "boost/type_traits/is_base_of.hpp"
+#include "boost/optional/detail/experimental_traits.hpp"
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+
+struct PrivDefault
+{
+  private: PrivDefault() {}
+};
+
+struct CustDefault
+{
+  CustDefault() {}
+};
+
+struct CustomizedTrivial
+{
+  CustomizedTrivial() {}
+};
+
+struct DeletedDefault
+{
+  BOOST_DELETED_FUNCTION(DeletedDefault())
+};
+
+namespace boost { namespace optional_config {
+  
+template <> struct optional_uses_direct_storage_for<CustomizedTrivial> : boost::true_type {};
+  
+}}
+
+struct CustDtor
+{
+  ~CustDtor() {}
+};
+
+struct NoDefault
+{
+  explicit NoDefault(int) {}
+};
+
+struct Empty {};
+
+template <typename T, typename U>
+struct Aggregate { T t; U u; };
+
+struct CustAssign
+{
+  CustAssign& operator=(CustAssign const&) { return *this; }
+};
+
+struct CustMove
+{
+  CustMove(CustMove &&) {}
+};
+
+void test_type_traits()
+{
+  // this only tests if type traits are implemented correctly
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<int> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<double> ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<CustomizedTrivial> ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<PrivDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<NoDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, CustDefault> > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustDtor> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustAssign> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustMove> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, CustMove> > ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<int> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<double> ));
+
+ 
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<Empty> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, double> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<Aggregate<Empty, int>, double> > ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Empty> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, double> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<Aggregate<Empty, int>, double> > ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<PrivDefault> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<NoDefault> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<CustDefault> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, CustDefault> > )); 
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<DeletedDefault> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, DeletedDefault> > ));
+#endif  
+
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<DeletedDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, DeletedDefault> > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustDtor> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustAssign> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustMove> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, CustMove> > ));
+}
+
+void test_trivial_copyability()
+{
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<int>, boost::optional<int> > ));
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<double>, boost::optional<double> > ));
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<CustomizedTrivial>, boost::optional<CustomizedTrivial> > ));
+  BOOST_TEST_TRAIT_FALSE((boost::is_base_of<boost::optional_detail::tc_optional_base<DeletedDefault>, boost::optional<DeletedDefault> > ));
+  
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<int> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<double> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<CustomizedTrivial> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Empty> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Aggregate<int, double> > > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Aggregate<Aggregate<Empty, int>, double> > > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<DeletedDefault> > ));
+#endif
+}
+
+#endif
+
+int main()
+{
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+  test_type_traits();
+  test_trivial_copyability();
+#endif
+  return boost::report_errors();
+}

test/optional_test_io.cpp

@@ -21,7 +21,6 @@
 #include "boost/core/lightweight_test.hpp"
 
 using boost::optional;
-using boost::make_optional;
 
 template<class Opt>
 void test2( Opt o, Opt buff )
@@ -42,10 +41,10 @@ void test2( Opt o, Opt buff )
 template<class T>
 void test( T v, T w )
 {
-  test2( make_optional(v), optional<T>  ());
-  test2( make_optional(v), make_optional(w));
+  test2( boost::make_optional(v), optional<T>  ());
+  test2( boost::make_optional(v), boost::make_optional(w));
   test2( optional<T>  () , optional<T>  ());
-  test2( optional<T>  () , make_optional(w));
+  test2( optional<T>  () , boost::make_optional(w));
 }
 
 

test/optional_test_make_optional.cpp

@@ -0,0 +1,121 @@
+// 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/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/ignore_unused.hpp"
+#include "boost/core/is_same.hpp"
+#include "boost/core/lightweight_test.hpp"
+#include "boost/core/lightweight_test_trait.hpp"
+
+
+using boost::optional;
+using boost::make_optional;
+using boost::core::is_same;
+
+template <typename Expected, typename Deduced>
+void verify_type(Deduced)
+{
+  BOOST_TEST_TRAIT_TRUE(( is_same<Expected, Deduced> ));
+}
+  
+#if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
+struct MoveOnly
+{
+  int value;
+  explicit MoveOnly(int i) : value(i) {}
+  MoveOnly(MoveOnly && r) : value(r.value) { r.value = 0; }
+  MoveOnly& operator=(MoveOnly && r) { value = r.value; r.value = 0; return *this; }
+  
+private:
+  MoveOnly(MoveOnly const&);
+  void operator=(MoveOnly const&);
+};
+
+MoveOnly makeMoveOnly(int i)
+{
+  return MoveOnly(i);
+}
+
+void test_make_optional_for_move_only_type()
+{
+  verify_type< optional<MoveOnly> >(make_optional(makeMoveOnly(2)));
+  verify_type< optional<MoveOnly> >(make_optional(true, makeMoveOnly(2)));
+  
+  optional<MoveOnly> o1 = make_optional(makeMoveOnly(1));
+  BOOST_TEST (o1);
+  BOOST_TEST_EQ (1, o1->value);
+  
+  optional<MoveOnly> o2 = make_optional(true, makeMoveOnly(2));
+  BOOST_TEST (o2);
+  BOOST_TEST_EQ (2, o2->value);
+  
+  optional<MoveOnly> oN = make_optional(false, makeMoveOnly(2));
+  BOOST_TEST (!oN);
+}
+
+#endif // !defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
+
+void test_make_optional_for_optional()
+{
+  optional<int> oi;
+  verify_type< optional< optional<int> > >(make_optional(oi));
+  verify_type< optional< optional<int> > >(make_optional(true, oi));
+  
+  optional< optional<int> > ooi = make_optional(oi);
+  BOOST_TEST (ooi);
+  BOOST_TEST (!*ooi);
+  
+  optional< optional<int> > ooT = make_optional(true, oi);
+  BOOST_TEST (ooT);
+  BOOST_TEST (!*ooT);
+  
+  optional< optional<int> > ooF = make_optional(false, oi);
+  BOOST_TEST (!ooF);
+}
+
+void test_nested_make_optional()
+{
+  verify_type< optional< optional<int> > >(make_optional(make_optional(1)));
+  verify_type< optional< optional<int> > >(make_optional(true, make_optional(true, 2)));
+  
+  optional< optional<int> > oo1 = make_optional(make_optional(1));
+  BOOST_TEST (oo1);
+  BOOST_TEST (*oo1);
+  BOOST_TEST_EQ (1, **oo1);
+  
+  optional< optional<int> > oo2 = make_optional(true, make_optional(true, 2));
+  BOOST_TEST (oo2);
+  BOOST_TEST (*oo2);
+  BOOST_TEST_EQ (2, **oo2);
+  
+  optional< optional<int> > oo3 = make_optional(true, make_optional(false, 3));
+  BOOST_TEST (oo3);
+  BOOST_TEST (!*oo3);
+  
+  optional< optional<int> > oo4 = make_optional(false, make_optional(true, 4));
+  BOOST_TEST (!oo4);
+}
+
+int main()
+{
+#if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
+  test_make_optional_for_move_only_type();
+#endif
+  test_make_optional_for_optional();
+  test_nested_make_optional();
+
+  return boost::report_errors();
+}

test/optional_test_maybe_uninitialized_warning.cpp

@@ -0,0 +1,32 @@
+// 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/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+boost::optional<int> getitem();
+
+int main(int argc, const char *[])
+{
+  boost::optional<int> a = getitem();
+  boost::optional<int> b;
+
+  if (argc > 0)
+    b = argc;
+
+  if (a == b)
+    return 1;
+
+  return 0;
+}

test/optional_test_member_T.cpp

@@ -0,0 +1,44 @@
+// 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"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+
+struct Status
+{
+  enum T
+  {
+    DISCONNECTED,
+    CONNECTING,
+    CONNECTED,
+  };
+
+  T mValue;
+};
+
+void test_member_T()
+{
+  boost::optional<Status> x = Status();
+  x->mValue = Status::CONNECTED;
+  
+  BOOST_TEST(x->mValue == Status::CONNECTED);
+}
+
+int main()
+{
+  test_member_T();
+  return boost::report_errors();
+}

test/optional_test_ref_assign_portable_minimum.cpp

@@ -39,6 +39,7 @@ int main()
 {
   test_optional_ref_assignment<ScopeGuard>();
   test_optional_ref_assignment<Abstract>();
+  test_optional_ref_assignment< optional<int> >();
   
   return boost::report_errors();
 }

test/optional_test_ref_converting_ctor.cpp

@@ -102,6 +102,7 @@ int main()
   test_all_const_cases<int>();
   test_all_const_cases<ScopeGuard>();
   test_all_const_cases<Abstract>();
+  test_all_const_cases< optional<int> >();
   
   return boost::report_errors();
 }

test/optional_test_ref_fail_init_from_Trefref.cpp

@@ -10,6 +10,7 @@
 //  akrzemi1@gmail.com
 //
 #include "boost/optional.hpp"
+#include "boost/core/ignore_unused.hpp"
 
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
 //
@@ -18,6 +19,7 @@
 void optional_reference__test_no_init_from_Trefref()
 {
   boost::optional<const int&> opt = int(3);
+  boost::ignore_unused(opt);
 }
 
 #else

test/optional_test_ref_fail_init_from_Urefref.cpp

@@ -1,4 +1,4 @@
-// Copyright (C) 2014, andrzej Krzemienski.
+// Copyright (C) 2014, 2016 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
@@ -10,6 +10,7 @@
 //  akrzemi1@gmail.com
 //
 #include "boost/optional.hpp"
+#include "boost/core/ignore_unused.hpp"
 
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
 //
@@ -18,6 +19,7 @@
 void optional_reference__test_no_init_from_Urefref()
 {
   boost::optional<const int&> opt = long(3);
+  boost::ignore_unused(opt);
 }
 
 #else

test/optional_test_ref_portable_minimum.cpp

@@ -430,6 +430,23 @@ void test_swap()
   BOOST_TEST(boost::addressof(*o2_) == boost::addressof(v1));
 }
 
+template <typename T, typename U>
+void test_convertability_of_compatible_reference_types()
+{
+  typename concrete_type_of<T>::type v1(1);
+  optional<T&> oN, o1(v1);
+  optional<U&> uN(oN), u1(o1);
+  BOOST_TEST(!uN);
+  BOOST_TEST(u1);
+  BOOST_TEST(boost::addressof(*u1) == boost::addressof(*o1));
+  
+  uN = o1;
+  u1 = oN;
+  BOOST_TEST(!u1);
+  BOOST_TEST(uN);
+  BOOST_TEST(boost::addressof(*uN) == boost::addressof(*o1));
+}
+
 template <typename T>
 void test_optional_ref()
 {
@@ -465,10 +482,18 @@ int main()
   test_optional_ref<int>();
   test_optional_ref<ScopeGuard>();
   test_optional_ref<Abstract>();
+  test_optional_ref< optional<int> >();
   
   test_optional_const_ref<int>();
   test_optional_const_ref<ScopeGuard>();
   test_optional_const_ref<Abstract>();
+  test_optional_const_ref< optional<int> >();
+  
+  test_convertability_of_compatible_reference_types<int, const int>();
+  test_convertability_of_compatible_reference_types<Impl, Abstract>();
+  test_convertability_of_compatible_reference_types<Impl, const Abstract>();
+  test_convertability_of_compatible_reference_types<const Impl, const Abstract>();
+  test_convertability_of_compatible_reference_types<optional<int>, const optional<int> >();
   
   return boost::report_errors();
 }

test/optional_test_sfinae_friendly_ctor.cpp

@@ -0,0 +1,49 @@
+// 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"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+using boost::optional;
+
+#if (!defined BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT)
+
+struct X {};
+struct Y {};
+  
+struct Resource
+{
+  explicit Resource(const X&) {}
+};
+
+BOOST_STATIC_ASSERT((  boost::is_constructible<Resource, const X&>::value ));
+BOOST_STATIC_ASSERT(( !boost::is_constructible<Resource, const Y&>::value ));
+
+BOOST_STATIC_ASSERT((  boost::is_constructible<optional<Resource>, const X&>::value ));
+BOOST_STATIC_ASSERT(( !boost::is_constructible<optional<Resource>, const Y&>::value ));
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+BOOST_STATIC_ASSERT((  boost::is_constructible< optional< optional<int> >, optional<int> >::value ));
+BOOST_STATIC_ASSERT(( !boost::is_constructible< optional<int>, optional< optional<int> > >::value ));
+
+BOOST_STATIC_ASSERT((  boost::is_constructible< optional< optional<int> >, const optional<int>& >::value ));
+BOOST_STATIC_ASSERT(( !boost::is_constructible< optional<int>, const optional< optional<int> >& >::value ));
+
+BOOST_STATIC_ASSERT((  boost::is_constructible<optional<Resource>, const optional<X>&>::value ));
+BOOST_STATIC_ASSERT(( !boost::is_constructible<optional<Resource>, const optional<Y>&>::value ));
+#endif
+  
+#endif
+
+int main() { }

test/optional_test_sfinae_friendly_value_ctor.cpp

@@ -1,38 +0,0 @@
-// 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"
-
-#ifdef __BORLANDC__
-#pragma hdrstop
-#endif
-
-using boost::optional;
-
-#if (!defined BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT)
-
-struct X {};
-struct Y {};
-  
-struct Resource
-{
-  explicit Resource(const X&) {}
-};
-
-BOOST_STATIC_ASSERT(( boost::is_constructible<Resource, const X&>::value));
-BOOST_STATIC_ASSERT((!boost::is_constructible<Resource, const Y&>::value));
-
-BOOST_STATIC_ASSERT(( boost::is_constructible<optional<Resource>, const X&>::value));
-BOOST_STATIC_ASSERT((!boost::is_constructible<optional<Resource>, const Y&>::value));
-  
-#endif
-
-int main() { }

test/optional_test_static_properties.cpp

@@ -0,0 +1,146 @@
+// 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/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+#include "boost/core/lightweight_test_trait.hpp"
+#include "boost/type_traits/is_base_of.hpp"
+#include "boost/optional/detail/experimental_traits.hpp"
+
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+
+struct PrivDefault
+{
+  private: PrivDefault() {}
+};
+
+struct CustDefault
+{
+  CustDefault() {}
+};
+
+struct CustomizedTrivial
+{
+  CustomizedTrivial() {}
+};
+
+struct DeletedDefault
+{
+  BOOST_DELETED_FUNCTION(DeletedDefault())
+};
+
+namespace boost { namespace optional_config {
+  
+template <> struct optional_uses_direct_storage_for<CustomizedTrivial> : boost::true_type {};
+  
+}}
+
+struct CustDtor
+{
+  ~CustDtor() {}
+};
+
+struct NoDefault
+{
+  explicit NoDefault(int) {}
+};
+
+struct Empty {};
+
+template <typename T, typename U>
+struct Aggregate { T t; U u; };
+
+struct CustAssign
+{
+  CustAssign& operator=(CustAssign const&) { return *this; }
+};
+
+struct CustMove
+{
+  CustMove(CustMove &&) {}
+};
+
+void test_type_traits()
+{
+  // this only tests if type traits are implemented correctly
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<int> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<double> ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_config::optional_uses_direct_storage_for<CustomizedTrivial> ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<PrivDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<NoDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, CustDefault> > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustDtor> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustAssign> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<CustMove> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, CustMove> > ));
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<int> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<double> ));
+
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Empty> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, double> > ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<Aggregate<Empty, int>, double> > ));
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+  
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Empty> ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, double> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<Aggregate<Empty, int>, double> > ));
+  
+#endif  
+
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<DeletedDefault> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_config::optional_uses_direct_storage_for<Aggregate<int, DeletedDefault> > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustDtor> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustAssign> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<CustMove> ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<Aggregate<int, CustMove> > ));
+}
+
+void test_trivial_copyability()
+{
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<int>, boost::optional<int> > ));
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<double>, boost::optional<double> > ));
+  BOOST_TEST_TRAIT_TRUE((boost::is_base_of<boost::optional_detail::tc_optional_base<CustomizedTrivial>, boost::optional<CustomizedTrivial> > ));
+  BOOST_TEST_TRAIT_FALSE((boost::is_base_of<boost::optional_detail::tc_optional_base<DeletedDefault>, boost::optional<DeletedDefault> > ));
+  
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SPEC_FOR_TRIVIAL_TYPES
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<int> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<double> > ));
+  BOOST_TEST_TRAIT_TRUE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<CustomizedTrivial> > ));
+  
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<DeletedDefault> > ));
+#endif
+
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Empty> > ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Aggregate<int, double> > > ));
+  BOOST_TEST_TRAIT_FALSE(( boost::optional_detail::is_type_trivially_copyable<boost::optional<Aggregate<Aggregate<Empty, int>, double> > > ));
+}
+
+#endif
+
+int main()
+{
+#ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
+  test_type_traits();
+  test_trivial_copyability();
+#endif
+  return boost::report_errors();
+}

test/optional_test_tc_base.cpp

@@ -0,0 +1,76 @@
+// 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"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/core/lightweight_test.hpp"
+
+#if defined(BOOST_NO_CXX11_DELETED_FUNCTIONS)
+
+int main()
+{
+}
+
+#else
+
+#include <utility>
+
+struct NotDefaultConstructible
+{
+	NotDefaultConstructible() = delete;
+};
+
+void test_tc_base()
+{
+  boost::optional<NotDefaultConstructible> o;
+  
+  BOOST_TEST(boost::none == o);
+}
+
+struct S
+{
+
+};
+
+template<class T>
+struct W
+{
+	T& t_;
+
+	template<class... Args>
+	W(Args&&... args)
+		: t_(std::forward<Args>(args)...)
+	{
+	}
+};
+
+void test_value_init()
+{
+	{
+		S s;
+		W<S> w{s};
+	}
+	boost::optional<W<S&> > o;
+	BOOST_TEST(boost::none == o);
+}
+
+int main()
+{
+  test_tc_base();
+  test_value_init();
+  return boost::report_errors();
+}
+
+#endif

test/optional_xconfig_NO_LEGAL_CONVERT_FROM_REF_fail.cpp

@@ -15,7 +15,7 @@
 
 #if (defined BOOST_NO_CXX11_RVALUE_REFERENCES) || (!defined BOOST_OPTIONAL_CONFIG_NO_LEGAL_CONVERT_FROM_REF)
 
-static_assert(false, "failed as requested");
+# error "failed as requested"
 
 #else
 

test/testable_classes.hpp

@@ -12,6 +12,8 @@
 #ifndef BOOST_OPTIONAL_TEST_TESTABKE_CLASSES_AK_07JAN2015_HPP
 #define BOOST_OPTIONAL_TEST_TESTABKE_CLASSES_AK_07JAN2015_HPP
 
+#include "boost/optional/optional.hpp"
+
 struct ScopeGuard // no copy/move ctor/assign
 {
   int val_;
@@ -74,13 +76,23 @@ struct has_arrow<int>
   static const bool value = false;
 };
 
+template <>
+struct has_arrow< boost::optional<int> >
+{
+  static const bool value = false;
+};
+
 int& val(int& i) { return i; }
 int& val(Abstract& a) { return a.val(); }
+int& val(Impl& a) { return a.val(); }
 int& val(ScopeGuard& g) { return g.val(); }
+template <typename T> int& val(T& o) { return *o; }
 
 const int& val(const int& i) { return i; }
 const int& val(const Abstract& a) { return a.val(); }
+const int& val(const Impl& a) { return a.val(); }
 const int& val(const ScopeGuard& g) { return g.val(); }
+template <typename T> const int& val(const T& o) { return *o; }
 
 bool operator==(const Abstract& l, const Abstract& r) { return l.val() == r.val(); }
 bool operator==(const ScopeGuard& l, const ScopeGuard& r) { return l.val() == r.val(); }