MinGW doesn't have _exit either

Abort instead of assert if report_errors() not called

.travis.yml

@@ -28,6 +28,26 @@ matrix:
       compiler: g++
       env: TOOLSET=gcc COMPILER=g++ CXXSTD=03,11
 
+    - os: linux
+      compiler: g++-4.4
+      env: TOOLSET=gcc COMPILER=g++-4.4 CXXSTD=98,0x
+      addons:
+        apt:
+          packages:
+            - g++-4.4
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: g++-4.6
+      env: TOOLSET=gcc COMPILER=g++-4.6 CXXSTD=03,0x
+      addons:
+        apt:
+          packages:
+            - g++-4.6
+          sources:
+            - ubuntu-toolchain-r-test
+
     - os: linux
       compiler: g++-4.7
       env: TOOLSET=gcc COMPILER=g++-4.7 CXXSTD=03,11
@@ -89,6 +109,16 @@ matrix:
           sources:
             - ubuntu-toolchain-r-test
 
+    - os: linux
+      compiler: g++-8
+      env: TOOLSET=gcc COMPILER=g++-8 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - g++-8
+          sources:
+            - ubuntu-toolchain-r-test
+
     - os: linux
       compiler: clang++
       env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11
@@ -103,7 +133,6 @@ matrix:
             - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.5
 
     - os: linux
       compiler: clang++-3.6
@@ -112,20 +141,9 @@ matrix:
         apt:
           packages:
             - clang-3.6
+            - libstdc++-4.9-dev
           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
@@ -137,7 +155,6 @@ matrix:
             - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.8
 
     - os: linux
       compiler: clang++-3.9
@@ -149,7 +166,6 @@ matrix:
             - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.9
 
     - os: linux
       compiler: clang++-4.0
@@ -173,6 +189,25 @@ matrix:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-5.0
 
+    - os: linux
+      compiler: clang++-6.0
+      env: TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - clang-6.0
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-6.0
+
+    - os: linux
+      compiler: clang++-libc++
+      env: TOOLSET=clang COMPILER=clang++-libc++ CXXSTD=03,11,14,1z
+      addons:
+        apt:
+          packages:
+            - libc++-dev
+
     - os: osx
       compiler: clang++
       env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z

doc/core.qbk

@@ -41,7 +41,9 @@ criteria for inclusion is that the utility component be:
 [include addressof.qbk]
 [include checked_delete.qbk]
 [include demangle.qbk]
+[include empty_value.qbk]
 [include enable_if.qbk]
+[include exchange.qbk]
 [include explicit_operator_bool.qbk]
 [include ignore_unused.qbk]
 [include is_same.qbk]

doc/empty_value.qbk

@@ -0,0 +1,129 @@
+[/
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+]
+
+[section:empty_value empty_value]
+
+[simplesect Authors]
+
+* Glen Fernandes
+
+[endsimplesect]
+
+[section Overview]
+
+The header <boost/core/empty_value.hpp> provides the class template
+`boost::empty_value` for library authors to conveniently leverage the Empty
+Base Optimization to store objects of potentially empty types.
+
+[endsect]
+
+[section Examples]
+
+The following example shows `boost::empty_value` used to create a type that
+stores a pointer, comparer, and allocator, where the comparer and allocator
+could be empty types.
+
+```
+template<class Ptr, class Compare, class Allocator>
+class storage
+    : empty_value<Compare, 0>
+    , empty_value<Allocator, 1> {
+public:
+    storage()
+        : empty_value<Compare, 0>(empty_init_t())
+        , empty_value<Allocator, 1>(empty_init_t())
+        , ptr_() { }
+
+    storage(const Compare& c, const Allocator& a)
+        : empty_value<Compare, 0>(empty_init_t(), c)
+        , empty_value<Allocator, 1>(empty_init_t(), a)
+        , ptr_() { }
+
+    const Ptr& pointer() const {
+        return ptr_;
+    }
+
+    Ptr& pointer() {
+        return ptr_;
+    }
+
+    const Compare& compare() const {
+        return empty_value<Compare, 0>::get();
+    }
+
+    Compare& compare() {
+        return empty_value<Compare, 0>::get();
+    }
+
+    const Allocator& allocator() const {
+        return empty_value<Allocator, 1>::get();
+    }
+
+    Allocator& allocator() {
+        return empty_value<Allocator, 1>::get();
+    }
+
+private:
+    Ptr ptr_;
+};
+```
+
+[endsect]
+
+[section Reference]
+
+```
+namespace boost {
+
+struct empty_init_t { };
+
+template<class T, unsigned Index = 0, bool Empty = ``/see below/``>
+class empty_value {
+public:
+    empty_value() = default;
+
+    template<class... Args>
+    explicit empty_value(empty_init_t, Args&&... args);
+
+    const T& get() const;
+
+    T& get();
+};
+
+} /* boost */
+```
+
+[section Template parameters]
+
+[variablelist
+[[`T`][The type of value to store]]
+[[`Index`][Optional: Specify to create a distinct base type]]
+[[`Empty`][Optional: Specify to force inheritance from type]]]
+
+[endsect]
+
+[section Constructors]
+
+[variablelist
+[[`empty_value() = default;`][Default initialize the value]]
+[[`template<class... Args> empty_value(empty_init_t, Args&&... args);`]
+[Initialize the value with `std::forward<Args>(args)...`]]]
+
+[endsect]
+
+[section Member functions]
+
+[variablelist
+[[`const T& get() const;`][Returns the value]]
+[[`T& get();`][Returns the value]]]
+
+[endsect]
+
+[endsect]
+
+[endsect]

doc/exchange.qbk

@@ -0,0 +1,62 @@
+[/
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+]
+
+[section:exchange exchange]
+
+[simplesect Authors]
+
+* Glen Fernandes
+
+[endsimplesect]
+
+[section Overview]
+
+The header <boost/core/exchange.hpp> provides the function template
+`boost::exchange` which is an implementation of the `std::exchange`
+function introduced in C++14.
+
+[endsect]
+
+[section Examples]
+
+The following example shows `boost::exchange` used to simplify the
+implementation of a move constructor.
+
+```
+Node(Node&& other)
+  : head_(boost::exchange(other.head_, nullptr))
+  , tail_(boost::exchange(other.tail_, nullptr)) { }
+```
+
+[endsect]
+
+[section Reference]
+
+```
+namespace boost {
+  template<class T, class U = T>
+  constexpr T exchange(T& t, U&& u);
+}
+```
+[section Functions]
+
+[*`template<class T, class U = T> constexpr T exchange(T& t, U&& u);`]
+
+Equivalent to:
+
+```
+T v = std::move(t);
+t = std::forward<U>(u);
+return v;
+```
+
+[endsect]
+
+[endsect]
+
+[endsect]

include/boost/core/empty_value.hpp

@@ -0,0 +1,125 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_CORE_EMPTY_VALUE_HPP
+#define BOOST_CORE_EMPTY_VALUE_HPP
+
+#include <boost/config.hpp>
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#include <utility>
+#endif
+
+#if defined(BOOST_GCC_VERSION) && (BOOST_GCC_VERSION >= 40700)
+#define BOOST_DETAIL_EMPTY_VALUE_BASE
+#elif defined(BOOST_INTEL) && defined(_MSC_VER) && (_MSC_VER >= 1800)
+#define BOOST_DETAIL_EMPTY_VALUE_BASE
+#elif defined(BOOST_MSVC) && (BOOST_MSVC >= 1800)
+#define BOOST_DETAIL_EMPTY_VALUE_BASE
+#elif defined(BOOST_CLANG) && !defined(__CUDACC__)
+#if __has_feature(is_empty) && __has_feature(is_final)
+#define BOOST_DETAIL_EMPTY_VALUE_BASE
+#endif
+#endif
+
+namespace boost {
+
+template<class T>
+struct use_empty_value_base {
+    enum {
+#if defined(BOOST_DETAIL_EMPTY_VALUE_BASE)
+        value = __is_empty(T) && !__is_final(T)
+#else
+        value = false
+#endif
+    };
+};
+
+struct empty_init_t { };
+
+template<class T, unsigned N = 0, bool E = use_empty_value_base<T>::value>
+class empty_value {
+public:
+#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
+    empty_value() = default;
+#else
+    empty_value() { }
+#endif
+
+    empty_value(empty_init_t)
+        : value_() { }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+    template<class... Args>
+    explicit empty_value(empty_init_t, Args&&... args)
+        : value_(std::forward<Args>(args)...) { }
+#else
+    template<class U>
+    empty_value(empty_init_t, U&& value)
+        : value_(std::forward<U>(value)) { }
+#endif
+#else
+    template<class U>
+    empty_value(empty_init_t, const U& value)
+        : value_(value) { }
+#endif
+
+    const T& get() const BOOST_NOEXCEPT {
+        return value_;
+    }
+
+    T& get() BOOST_NOEXCEPT {
+        return value_;
+    }
+
+private:
+    T value_;
+};
+
+#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+template<class T, unsigned N>
+class empty_value<T, N, true>
+    : T {
+public:
+#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
+    empty_value() = default;
+#else
+    empty_value() { }
+#endif
+
+    empty_value(empty_init_t)
+        : T() { }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+    template<class... Args>
+    explicit empty_value(empty_init_t, Args&&... args)
+        : T(std::forward<Args>(args)...) { }
+#else
+    template<class U>
+    empty_value(empty_init_t, U&& value)
+        : T(std::forward<U>(value)) { }
+#endif
+#else
+    template<class U>
+    empty_value(empty_init_t, const U& value)
+        : T(value) { }
+#endif
+
+    const T& get() const BOOST_NOEXCEPT {
+        return *this;
+    }
+
+    T& get() BOOST_NOEXCEPT {
+        return *this;
+    }
+};
+#endif
+
+} /* boost */
+
+#endif

include/boost/core/exchange.hpp

@@ -0,0 +1,49 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_CORE_EXCHANGE_HPP
+#define BOOST_CORE_EXCHANGE_HPP
+
+#include <boost/config.hpp>
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#include <boost/config/workaround.hpp>
+#include <utility>
+#endif
+
+namespace boost {
+
+#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+template<class T, class U>
+inline T exchange(T& t, const U& u)
+{
+    T v = t;
+    t = u;
+    return v;
+}
+#else
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1800)
+template<class T, class U>
+inline T exchange(T& t, U&& u)
+{
+    T v = std::move(t);
+    t = std::forward<U>(u);
+    return v;
+}
+#else
+template<class T, class U = T>
+BOOST_CXX14_CONSTEXPR inline T exchange(T& t, U&& u)
+{
+    T v = std::move(t);
+    t = std::forward<U>(u);
+    return v;
+}
+#endif
+#endif
+
+} /* boost */
+
+#endif

include/boost/core/explicit_operator_bool.hpp

@@ -19,6 +19,7 @@
 #define BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
 
 #include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
 
 #ifdef BOOST_HAS_PRAGMA_ONCE
 #pragma once
@@ -52,6 +53,8 @@
         return !this->operator! ();\
     }
 
+#if !BOOST_WORKAROUND(BOOST_GCC, < 40700)
+
 /*!
  * \brief The macro defines a constexpr explicit operator of conversion to \c bool
  *
@@ -65,6 +68,12 @@
         return !this->operator! ();\
     }
 
+#else
+
+#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL() BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
+
+#endif
+
 #else // !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
 
 #if (defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530)) && !defined(BOOST_NO_COMPILER_CONFIG)

include/boost/core/lightweight_test.hpp

@@ -14,16 +14,19 @@
 //  Copyright (2) Beman Dawes 2010, 2011
 //  Copyright (3) Ion Gaztanaga 2013
 //
+//  Copyright 2018 Glen Joseph Fernandes
+//  (glenjofe@gmail.com)
+//
 //  Distributed under the Boost Software License, Version 1.0.
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 //
 
 #include <boost/core/no_exceptions_support.hpp>
-#include <boost/assert.hpp>
 #include <boost/current_function.hpp>
 #include <iostream>
 #include <iterator>
+#include <cstdlib>
 #include <cstring>
 #include <cstddef>
 
@@ -39,29 +42,52 @@ namespace boost
 namespace detail
 {
 
-struct report_errors_reminder
-{
-    bool called_report_errors_function;
-
-    report_errors_reminder() : called_report_errors_function(false) {}
-
-    ~report_errors_reminder()
-    {
-        BOOST_ASSERT(called_report_errors_function);  // verify report_errors() was called  
+class test_result {
+public:
+    test_result()
+        : report_(false)
+        , errors_(0) {
+#if defined(_MSC_VER)
+        ::_set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
+#endif
     }
+
+    ~test_result() {
+        if (!report_) {
+            BOOST_LIGHTWEIGHT_TEST_OSTREAM << "main() should return report_errors()" << std::endl;
+
+#if defined(_MSC_VER)
+            ::_exit( 3 );
+#elif defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
+            std::abort();
+#else
+            ::_Exit( 3 );
+#endif
+        }
+    }
+
+    int& errors() {
+        return errors_;
+    }
+
+    void done() {
+        report_ = true;
+    }
+
+private:
+    bool report_;
+    int errors_;
 };
 
-inline report_errors_reminder& report_errors_remind()
+inline test_result& test_results()
 {
-    static report_errors_reminder r;
-    return r;
+    static test_result instance;
+    return instance;
 }
 
-inline int & test_errors()
+inline int& test_errors()
 {
-    static int x = 0;
-    report_errors_remind();
-    return x;
+    return test_results().errors();
 }
 
 inline void test_failed_impl(char const * expr, char const * file, int line, char const * function)
@@ -69,7 +95,7 @@ inline void test_failed_impl(char const * expr, char const * file, int line, cha
     BOOST_LIGHTWEIGHT_TEST_OSTREAM
       << file << "(" << line << "): test '" << expr << "' failed in function '"
       << function << "'" << std::endl;
-    ++test_errors();
+    ++test_results().errors();
 }
 
 inline void error_impl(char const * msg, char const * file, int line, char const * function)
@@ -77,7 +103,7 @@ inline void error_impl(char const * msg, char const * file, int line, char const
     BOOST_LIGHTWEIGHT_TEST_OSTREAM
       << file << "(" << line << "): " << msg << " in function '"
       << function << "'" << std::endl;
-    ++test_errors();
+    ++test_results().errors();
 }
 
 inline void throw_failed_impl(char const * excep, char const * file, int line, char const * function)
@@ -85,7 +111,7 @@ inline void throw_failed_impl(char const * excep, char const * file, int line, c
    BOOST_LIGHTWEIGHT_TEST_OSTREAM
     << file << "(" << line << "): Exception '" << excep << "' not thrown in function '"
     << function << "'" << std::endl;
-   ++test_errors();
+   ++test_results().errors();
 }
 
 // In the comparisons below, it is possible that T and U are signed and unsigned integer types, which generates warnings in some compilers.
@@ -118,105 +144,58 @@ template<class T> inline const void* test_output_impl(T volatile* v) { return co
 inline const void* test_output_impl(std::nullptr_t) { return nullptr; }
 #endif
 
-template<class T, class U> inline void test_eq_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
-{
-    if( t == u )
-    {
-        report_errors_remind();
-    }
-    else
-    {
-        BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " == " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' != '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
-    }
-}
+struct lw_test_eq {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t == u; }
+    static const char* op() { return "=="; }
+};
 
-template<class T, class U> inline void test_ne_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
-{
-    if( t != u )
-    {
-        report_errors_remind();
-    }
-    else
-    {
-        BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " != " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' == '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
-    }
-}
+struct lw_test_ne {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t != u; }
+    static const char* op() { return "!="; }
+};
 
-template<class T, class U> inline void test_lt_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
-{
-    if( t < u )
-    {
-        report_errors_remind();
-    }
-    else
-    {
-        BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " < " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' >= '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
-    }
-}
+struct lw_test_lt {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t < u; }
+    static const char* op() { return "<"; }
+};
 
-template<class T, class U> inline void test_le_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
-{
-    if( t <= u )
-    {
-        report_errors_remind();
-    }
-    else
-    {
-        BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " <= " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' > '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
-    }
-}
+struct lw_test_le {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t <= u; }
+    static const char* op() { return "<="; }
+};
 
-template<class T, class U> inline void test_gt_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
-{
-    if( t > u )
-    {
-        report_errors_remind();
-    }
-    else
-    {
-        BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " > " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' <= '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
-    }
-}
+struct lw_test_gt {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t > u; }
+    static const char* op() { return ">"; }
+};
 
-template<class T, class U> inline void test_ge_impl( char const * expr1, char const * expr2,
-  char const * file, int line, char const * function, T const & t, U const & u )
+struct lw_test_ge {
+    template <typename T, typename U>
+    bool operator()(const T& t, const U& u) const { return t >= u; }
+    static const char* op() { return ">="; }
+};
+
+template<class BinaryPredicate, class T, class U>
+inline void test_with_impl(BinaryPredicate pred, char const * expr1, char const * expr2,
+                           char const * file, int line, char const * function,
+                           T const & t, U const & u)
 {
-    if( t >= u )
+    if( pred(t, u) )
     {
-        report_errors_remind();
+        test_results();
     }
     else
     {
         BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " >= " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << test_output_impl(t) << "' < '" << test_output_impl(u) << "'" << std::endl;
-        ++test_errors();
+            << file << "(" << line << "): test '" << expr1 << " " << pred.op() << " " << expr2
+            << "' ('" << test_output_impl(t) << "' " << pred.op() << " '" << test_output_impl(u)
+            << "') failed in function '" << function << "'" << std::endl;
+        ++test_results().errors();
     }
 }
 
@@ -225,15 +204,14 @@ inline void test_cstr_eq_impl( char const * expr1, char const * expr2,
 {
     if( std::strcmp(t, u) == 0 )
     {
-        report_errors_remind();
+        test_results();
     }
     else
     {
         BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " == " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << t << "' != '" << u << "'" << std::endl;
-        ++test_errors();
+            << file << "(" << line << "): test '" << expr1 << " == " << expr2 << "' ('" << t
+            << "' == '" << u << "') failed in function '" << function << "'" << std::endl;
+        ++test_results().errors();
     }
 }
 
@@ -242,15 +220,14 @@ inline void test_cstr_ne_impl( char const * expr1, char const * expr2,
 {
     if( std::strcmp(t, u) != 0 )
     {
-        report_errors_remind();
+        test_results();
     }
     else
     {
         BOOST_LIGHTWEIGHT_TEST_OSTREAM
-            << file << "(" << line << "): test '" << expr1 << " == " << expr2
-            << "' failed in function '" << function << "': "
-            << "'" << t << "' == '" << u << "'" << std::endl;
-        ++test_errors();
+            << file << "(" << line << "): test '" << expr1 << " != " << expr2 << "' ('" << t
+            << "' != '" << u << "') failed in function '" << function << "'" << std::endl;
+        ++test_results().errors();
     }
 }
 
@@ -313,12 +290,12 @@ void test_all_eq_impl(FormattedOutputFunction& output,
 
     if (error_count == 0)
     {
-        boost::detail::report_errors_remind();
+        test_results();
     }
     else
     {
         output << std::endl;
-        ++boost::detail::test_errors();
+        ++test_results().errors();
     }
 }
 
@@ -382,12 +359,12 @@ void test_all_with_impl(FormattedOutputFunction& output,
 
     if (error_count == 0)
     {
-        report_errors_remind();
+        test_results();
     }
     else
     {
         output << std::endl;
-        ++test_errors();
+        ++test_results().errors();
     }
 }
 
@@ -405,10 +382,10 @@ void test_all_with_impl(FormattedOutputFunction& output,
 
 inline int report_errors()
 {
-    boost::detail::report_errors_remind().called_report_errors_function = true;
-
-    int errors = boost::detail::test_errors();
+    boost::detail::test_result& result = boost::detail::test_results();
+    result.done();
 
+    int errors = result.errors();
     if( errors == 0 )
     {
         BOOST_LIGHTWEIGHT_TEST_OSTREAM
@@ -425,18 +402,18 @@ inline int report_errors()
 
 } // namespace boost
 
-#define BOOST_TEST(expr) ((expr)? (void)0: ::boost::detail::test_failed_impl(#expr, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION))
+#define BOOST_TEST(expr) ((expr)? (void)::boost::detail::test_results(): ::boost::detail::test_failed_impl(#expr, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION))
 #define BOOST_TEST_NOT(expr) BOOST_TEST(!(expr))
 
 #define BOOST_ERROR(msg) ( ::boost::detail::error_impl(msg, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
 
-#define BOOST_TEST_EQ(expr1,expr2) ( ::boost::detail::test_eq_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
-#define BOOST_TEST_NE(expr1,expr2) ( ::boost::detail::test_ne_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_EQ(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_eq(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_NE(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_ne(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
 
-#define BOOST_TEST_LT(expr1,expr2) ( ::boost::detail::test_lt_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
-#define BOOST_TEST_LE(expr1,expr2) ( ::boost::detail::test_le_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
-#define BOOST_TEST_GT(expr1,expr2) ( ::boost::detail::test_gt_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
-#define BOOST_TEST_GE(expr1,expr2) ( ::boost::detail::test_ge_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_LT(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_lt(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_LE(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_le(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_GT(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_gt(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
+#define BOOST_TEST_GE(expr1,expr2) ( ::boost::detail::test_with_impl(::boost::detail::lw_test_ge(), #expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
 
 #define BOOST_TEST_CSTR_EQ(expr1,expr2) ( ::boost::detail::test_cstr_eq_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )
 #define BOOST_TEST_CSTR_NE(expr1,expr2) ( ::boost::detail::test_cstr_ne_impl(#expr1, #expr2, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION, expr1, expr2) )

include/boost/core/lightweight_test_trait.hpp

@@ -31,7 +31,7 @@ template< class T > inline void test_trait_impl( char const * trait, void (*)( T
 {
     if( T::value == expected )
     {
-        report_errors_remind();
+        test_results();
     }
     else
     {
@@ -42,7 +42,7 @@ template< class T > inline void test_trait_impl( char const * trait, void (*)( T
             << "' (should have been " << ( expected? "true": "false" ) << ")"
             << std::endl;
 
-        ++test_errors();
+        ++test_results().errors();
     }
 }
 

include/boost/core/noncopyable.hpp

@@ -20,7 +20,22 @@ namespace boost {
 
 namespace noncopyable_  // protection from unintended ADL
 {
-  class noncopyable
+#ifndef BOOST_NONCOPYABLE_BASE_TOKEN_DEFINED
+#define BOOST_NONCOPYABLE_BASE_TOKEN_DEFINED
+
+// noncopyable derives from base_token to enable Type Traits to detect
+// whether a type derives from noncopyable without needing the definition
+// of noncopyable itself.
+//
+// The definition of base_token is macro-guarded so that Type Trais can
+// define it locally without including this header, to avoid a dependency
+// on Core.
+
+  struct base_token {};
+
+#endif // #ifndef BOOST_NONCOPYABLE_BASE_TOKEN_DEFINED
+
+  class noncopyable: base_token
   {
   protected:
 #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) && !defined(BOOST_NO_CXX11_NON_PUBLIC_DEFAULTED_FUNCTIONS)

test/Jamfile.v2

@@ -68,15 +68,14 @@ run get_pointer_test.cpp ;
 
 run lightweight_test_test.cpp ;
 run lightweight_test_test.cpp : : : <exception-handling>off : lightweight_test_test_no_except ;
-
 run lightweight_test_test2.cpp ;
 run lightweight_test_all_eq_test.cpp ;
 run lightweight_test_all_with_test.cpp ;
 run lightweight_test_all_with_fail.cpp ;
 run lightweight_test_lt_le_test.cpp ;
 run lightweight_test_gt_ge_test.cpp ;
-
 run lightweight_test_eq_nullptr.cpp ;
+run lightweight_test_test3.cpp ;
 
 run-fail lightweight_test_fail.cpp ;
 run-fail lightweight_test_fail2.cpp ;
@@ -90,6 +89,7 @@ run-fail lightweight_test_fail8.cpp ;
 run-fail lightweight_test_fail8.cpp : : : <rtti>off : lightweight_test_fail8_no_rtti ;
 run-fail lightweight_test_fail9.cpp ;
 run-fail lightweight_test_fail10.cpp ;
+run-fail lightweight_test_fail11.cpp ;
 run-fail lightweight_test_lt_fail.cpp ;
 run-fail lightweight_test_le_fail.cpp ;
 run-fail lightweight_test_gt_fail.cpp ;
@@ -121,5 +121,11 @@ run pointer_traits_rebind_test.cpp ;
 run pointer_traits_pointer_to_test.cpp ;
 run to_address_test.cpp ;
 
+run exchange_test.cpp ;
+run exchange_move_test.cpp ;
+
+run empty_value_test.cpp ;
+run empty_value_size_test.cpp ;
+
 use-project /boost/core/swap : ./swap ;
 build-project ./swap ;

test/empty_value_size_test.cpp

@@ -0,0 +1,60 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+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_TEMPLATE_PARTIAL_SPECIALIZATION)
+#include <boost/core/empty_value.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct T1 { };
+
+struct S1
+    : boost::empty_value<T1, 0, true> { };
+
+struct T2 {
+    int value;
+};
+
+struct S2
+    : boost::empty_value<T1, 0, true>
+    , boost::empty_value<T2, 1, true> { };
+
+struct S3
+    : boost::empty_value<T1, 0, false>
+    , boost::empty_value<T2, 1, true> { };
+
+struct T3 { };
+
+struct S4
+    : boost::empty_value<T1, 0, true>
+    , boost::empty_value<T3, 1, true> { };
+
+struct S5
+    : boost::empty_value<T1, 0, false>
+    , boost::empty_value<T3, 1, false> { };
+
+struct S6
+    : boost::empty_value<T1, 0, true>
+    , boost::empty_value<T2, 1, true>
+    , boost::empty_value<T3, 2, true> { };
+
+int main()
+{
+    BOOST_TEST(sizeof(S1) == sizeof(T1));
+    BOOST_TEST(sizeof(S2) == sizeof(T2));
+    BOOST_TEST(sizeof(S3) > sizeof(T2));
+    BOOST_TEST(sizeof(S4) == sizeof(T1));
+    BOOST_TEST(sizeof(S5) > sizeof(T1));
+    BOOST_TEST(sizeof(S6) == sizeof(T2));
+    return boost::report_errors();
+}
+#else
+int main()
+{
+    return 0;
+}
+#endif

test/empty_value_test.cpp

@@ -0,0 +1,76 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/empty_value.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct empty {
+    operator bool() const {
+        return false;
+    }
+    operator bool() {
+        return true;
+    }
+};
+
+class type {
+public:
+    type()
+        : value_(false) { }
+    explicit type(bool value)
+        : value_(value) { }
+    operator bool() const {
+        return value_;
+    }
+private:
+    bool value_;
+};
+
+void test_bool()
+{
+    const boost::empty_value<bool> v1(boost::empty_init_t(), true);
+    BOOST_TEST(v1.get());
+    boost::empty_value<bool> v2 = boost::empty_init_t();
+    BOOST_TEST(!v2.get());
+    v2 = v1;
+    BOOST_TEST(v2.get());
+    v2.get() = false;
+    BOOST_TEST(!v2.get());
+}
+
+void test_empty()
+{
+    empty e;
+    const boost::empty_value<empty> v1(boost::empty_init_t(), e);
+    BOOST_TEST(!v1.get());
+    boost::empty_value<empty> v2;
+    BOOST_TEST(v2.get());
+    v2 = v1;
+    BOOST_TEST(v2.get());
+    v2.get() = empty();
+    BOOST_TEST(v2.get());
+}
+
+void test_type()
+{
+    const boost::empty_value<type> v1(boost::empty_init_t(), true);
+    BOOST_TEST(v1.get());
+    boost::empty_value<type> v2;
+    BOOST_TEST(!v2.get());
+    v2 = v1;
+    BOOST_TEST(v2.get());
+    v2.get() = type();
+    BOOST_TEST(!v2.get());
+}
+
+int main()
+{
+    test_bool();
+    test_empty();
+    test_type();
+    return boost::report_errors();
+}

test/exchange_move_test.cpp

@@ -0,0 +1,100 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+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_RVALUE_REFERENCES)
+#include <boost/core/exchange.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+class C1 {
+public:
+    explicit C1(int i)
+        : i_(i) { }
+    C1(C1&& c)
+        : i_(c.i_) { }
+    C1& operator=(C1&& c) {
+        i_ = c.i_;
+        return *this;
+    }
+    int i() const {
+        return i_;
+    }
+private:
+    C1(const C1&);
+    C1& operator=(const C1&);
+    int i_;
+};
+
+void test1()
+{
+    C1 x(1);
+    BOOST_TEST(boost::exchange(x, C1(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+class C2 {
+public:
+    explicit C2(int i)
+        : i_(i) { }
+    operator C1() const {
+        return C1(i_);
+    }
+    int i() const {
+        return i_;
+    }
+private:
+    C2(const C2&);
+    C2& operator=(const C2&);
+    int i_;
+};
+
+void test2()
+{
+    C1 x(1);
+    BOOST_TEST(boost::exchange(x, C2(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+class C3 {
+public:
+    explicit C3(int i)
+        : i_(i) { }
+    C3(C3&& c)
+        : i_(c.i_) { }
+    C3& operator=(C1&& c) {
+        i_ = c.i();
+        return *this;
+    }
+    int i() const {
+        return i_;
+    }
+private:
+    C3(const C3&);
+    C3& operator=(const C3&);
+    int i_;
+};
+
+void test3()
+{
+    C3 x(1);
+    BOOST_TEST(boost::exchange(x, C1(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+int main()
+{
+    test1();
+    test2();
+    test3();
+    return boost::report_errors();
+}
+#else
+int main()
+{
+    return 0;
+}
+#endif

test/exchange_test.cpp

@@ -0,0 +1,89 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/exchange.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+void test1()
+{
+    int i = 1;
+    BOOST_TEST(boost::exchange(i, 2) == 1);
+    BOOST_TEST(i == 2);
+}
+
+class C1 {
+public:
+    explicit C1(int i)
+        : i_(i) { }
+    int i() const {
+        return i_;
+    }
+private:
+    int i_;
+};
+
+void test2()
+{
+    C1 x(1);
+    BOOST_TEST(boost::exchange(x, C1(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+class C2 {
+public:
+    explicit C2(int i)
+        : i_(i) { }
+    operator C1() const {
+        return C1(i_);
+    }
+    int i() const {
+        return i_;
+    }
+private:
+    int i_;
+};
+
+void test3()
+{
+    C1 x(1);
+    BOOST_TEST(boost::exchange(x, C2(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+class C3 {
+public:
+    explicit C3(int i)
+        : i_(i) { }
+    C3(const C3& c)
+        : i_(c.i_) { }
+    C3& operator=(const C1& c) {
+        i_ = c.i();
+        return *this;
+    }
+    int i() const {
+        return i_;
+    }
+private:
+    C3& operator=(const C3&);
+    int i_;
+};
+
+void test4()
+{
+    C3 x(1);
+    BOOST_TEST(boost::exchange(x, C1(2)).i() == 1);
+    BOOST_TEST(x.i() == 2);
+}
+
+int main()
+{
+    test1();
+    test2();
+    test3();
+    test4();
+    return boost::report_errors();
+}

test/lightweight_test_all_eq_test.cpp

@@ -120,7 +120,5 @@ int main()
         ++test_cases;
     }
 
-    boost::report_errors();
-
-    return boost::detail::test_errors() != test_cases;
+    return !boost::report_errors();
 }

test/lightweight_test_all_with_fail.cpp

@@ -101,7 +101,5 @@ int main()
     test_cases += fail_vector();
     test_cases += fail_tolerance_predicate();
 
-    boost::report_errors();
-
-    return boost::detail::test_errors() != test_cases;
+    return !boost::report_errors();
 }

test/lightweight_test_eq_nullptr.cpp

@@ -22,6 +22,9 @@ int main()
     BOOST_TEST_EQ( p1, nullptr );
     BOOST_TEST_NE( p2, nullptr );
 
+    BOOST_TEST_EQ( nullptr, p1 );
+    BOOST_TEST_NE( nullptr, p2 );
+
 #endif
 
     return boost::report_errors();

test/lightweight_test_fail11.cpp

@@ -0,0 +1,14 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/lightweight_test.hpp>
+
+int main()
+{
+    BOOST_TEST(true);
+    return 0;
+}

test/lightweight_test_test3.cpp

@@ -0,0 +1,147 @@
+//
+// Test for lightweight_test.hpp
+//
+// Copyright (c) 2014, 2018 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/noncopyable.hpp>
+#include <ostream>
+
+// EQ
+
+struct eq1: private boost::noncopyable {};
+struct eq2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, eq1 const& )
+{
+    return os << "eq1()";
+}
+
+std::ostream& operator<<( std::ostream& os, eq2 const& )
+{
+    return os << "eq2()";
+}
+
+bool operator==( eq1 const&, eq2 const& )
+{
+    return true;
+}
+
+// NE
+
+struct ne1: private boost::noncopyable {};
+struct ne2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, ne1 const& )
+{
+    return os << "ne1()";
+}
+
+std::ostream& operator<<( std::ostream& os, ne2 const& )
+{
+    return os << "ne2()";
+}
+
+bool operator!=( ne1 const&, ne2 const& )
+{
+    return true;
+}
+
+// LT
+
+struct lt1: private boost::noncopyable {};
+struct lt2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, lt1 const& )
+{
+    return os << "lt1()";
+}
+
+std::ostream& operator<<( std::ostream& os, lt2 const& )
+{
+    return os << "lt2()";
+}
+
+bool operator<( lt1 const&, lt2 const& )
+{
+    return true;
+}
+
+// LE
+
+struct le1: private boost::noncopyable {};
+struct le2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, le1 const& )
+{
+    return os << "le1()";
+}
+
+std::ostream& operator<<( std::ostream& os, le2 const& )
+{
+    return os << "le2()";
+}
+
+bool operator<=( le1 const&, le2 const& )
+{
+    return true;
+}
+
+// GT
+
+struct gt1: private boost::noncopyable {};
+struct gt2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, gt1 const& )
+{
+    return os << "gt1()";
+}
+
+std::ostream& operator<<( std::ostream& os, gt2 const& )
+{
+    return os << "gt2()";
+}
+
+bool operator>( gt1 const&, gt2 const& )
+{
+    return true;
+}
+
+// GE
+
+struct ge1: private boost::noncopyable {};
+struct ge2: private boost::noncopyable {};
+
+std::ostream& operator<<( std::ostream& os, ge1 const& )
+{
+    return os << "ge1()";
+}
+
+std::ostream& operator<<( std::ostream& os, ge2 const& )
+{
+    return os << "ge2()";
+}
+
+bool operator>=( ge1 const&, ge2 const& )
+{
+    return true;
+}
+
+//
+
+int main()
+{
+    BOOST_TEST_EQ( eq1(), eq2() );
+    BOOST_TEST_NE( ne1(), ne2() );
+    BOOST_TEST_LT( lt1(), lt2() );
+    BOOST_TEST_LE( le1(), le2() );
+    BOOST_TEST_GT( gt1(), gt2() );
+    BOOST_TEST_GE( ge1(), ge2() );
+
+    return boost::report_errors();
+}