Split gcc 8/9 Travis jobs (again) due to log size

atomic_count_std_atomic: static_cast v to std::int_least32_t

.travis.yml

@@ -6,6 +6,8 @@ language: cpp
 
 sudo: false
 
+dist: trusty
+
 branches:
   only:
     - master
@@ -125,6 +127,26 @@ matrix:
           sources:
             - ubuntu-toolchain-r-test
 
+    - os: linux
+      compiler: g++-9
+      env: TOOLSET=gcc COMPILER=g++-9 CXXSTD=03,11,14
+      addons:
+        apt:
+          packages:
+            - g++-9
+          sources:
+            - ubuntu-toolchain-r-test
+
+    - os: linux
+      compiler: g++-9
+      env: TOOLSET=gcc COMPILER=g++-9 CXXSTD=17,2a
+      addons:
+        apt:
+          packages:
+            - g++-9
+          sources:
+            - ubuntu-toolchain-r-test
+
     - os: linux
       compiler: g++-7
       env: UBSAN=1 TOOLSET=gcc COMPILER=g++-7 CXXSTD=03,11,14,17 UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
@@ -257,6 +279,17 @@ matrix:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-7
 
+    - os: linux
+      compiler: clang++-8
+      env: TOOLSET=clang COMPILER=clang++-8 CXXSTD=03,11,14,17,2a
+      addons:
+        apt:
+          packages:
+            - clang-8
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-8
+
     - os: linux
       compiler: clang++-7
       env: UBSAN=1 TOOLSET=clang COMPILER=clang++-7 CXXSTD=03,11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1

doc/smart_ptr.adoc

@@ -33,6 +33,8 @@ include::smart_ptr/make_shared.adoc[]
 
 include::smart_ptr/enable_shared_from_this.adoc[]
 
+include::smart_ptr/enable_shared_from.adoc[]
+
 include::smart_ptr/make_unique.adoc[]
 
 include::smart_ptr/intrusive_ptr.adoc[]

doc/smart_ptr/changelog.adoc

@@ -17,3 +17,9 @@ http://www.boost.org/LICENSE_1_0.txt
 
 * Added aliasing constructors to `weak_ptr`
 * Added `weak_ptr<T>::empty()`
+* Added `enable_shared_from`, `shared_from`, and `weak_from`
+
+## Changes in 1.65.0
+
+* Added `atomic_shared_ptr`
+* Added `local_shared_ptr`, `make_local_shared`

doc/smart_ptr/enable_shared_from.adoc

@@ -0,0 +1,89 @@
+////
+Copyright 2002, 2003, 2015, 2017, 2019 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
+////
+
+[#enable_shared_from]
+# enable_shared_from
+:toc:
+:toc-title:
+:idprefix: enable_shared_from_
+
+## Description
+
+`enable_shared_from` is used as a base class that allows a `shared_ptr` or a
+`weak_ptr` to be obtained given a raw pointer to the object, by using the
+functions `shared_from` and `weak_from`.
+
+`enable_shared_from` differs from `enable_shared_from_this<T>` by the fact
+that it's not a template, and is its recommended replacement for new code.
+
+## Example
+
+```
+#include <boost/smart_ptr/enable_shared_from.hpp>
+#include <boost/shared_ptr.hpp>
+#include <cassert>
+
+class Y: public boost::enable_shared_from
+{
+public:
+
+    boost::shared_ptr<Y> f()
+    {
+        return boost::shared_from( this );
+    }
+};
+
+int main()
+{
+    boost::shared_ptr<Y> p(new Y);
+    boost::shared_ptr<Y> q = p->f();
+    assert(p == q);
+    assert(!(p < q || q < p)); // p and q must share ownership
+}
+```
+
+## Synopsis
+
+`enable_shared_from` is defined in `<boost/smart_ptr/enable_shared_from.hpp>`.
+
+```
+namespace boost {
+
+  class enable_shared_from: public enable_shared_from_this<enable_shared_from>
+  {
+  };
+
+  template<class T> shared_ptr<T> shared_from( T * p );
+  template<class T> weak_ptr<T> weak_from( T * p ) noexcept;
+}
+```
+
+## Functions
+
+```
+template<class T> shared_ptr<T> shared_from( T * p );
+```
+[none]
+* {blank}
++
+Returns:: `shared_ptr<T>( p\->enable_shared_from::shared_from_this(), p )`.
+
+NOTE: Throws `bad_weak_ptr` when `p` is not owned by a `shared_ptr`.
+
+```
+template<class T> weak_ptr<T> weak_from( T * p ) noexcept;
+```
+[none]
+* {blank}
++
+Returns:: `weak_ptr<T>( p\->enable_shared_from::weak_from_this(), p )`.
+
+NOTE: Unlike `shared_from(this)`, `weak_from(this)` is valid in a destructor
+      and returns a `weak_ptr` that is `expired()` but still shares ownership
+      with other `weak_ptr` instances (if any) that refer to the object.

doc/smart_ptr/enable_shared_from_this.adoc

@@ -142,3 +142,7 @@ template<class T> weak_ptr<T const> weak_from_this() const noexcept;
 * {blank}
 +
 Returns:: `weak_this_`.
+
+NOTE: Unlike `shared_from_this()`, `weak_from_this()` is valid in a destructor
+      and returns a `weak_ptr` that is `expired()` but still shares ownership
+      with other `weak_ptr` instances (if any) that refer to the object.

include/boost/smart_ptr/allocate_local_shared_array.hpp

@@ -72,21 +72,19 @@ inline typename enable_if_<is_unbounded_array<T>::value,
     local_shared_ptr<T> >::type
 allocate_local_shared(const A& allocator, std::size_t count)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
     typedef detail::lsp_array_state<other> state;
     typedef detail::sp_array_base<state> base;
-    std::size_t size = count * detail::sp_array_count<type, scalar>::value;
-    detail::sp_array_result<other, base> result(allocator, size);
+    detail::sp_array_result<other, base> result(allocator, count);
     base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size, start);
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
     detail::lsp_array_base& local = node->state().base();
     local.set(node);
     result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(), start,
+        &local);
 }
 
 template<class T, class A>
@@ -94,23 +92,22 @@ inline typename enable_if_<is_bounded_array<T>::value,
     local_shared_ptr<T> >::type
 allocate_local_shared(const A& allocator)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
     enum {
-        size = detail::sp_array_count<T, scalar>::value
+        count = extent<T>::value
     };
-    typedef detail::lsp_size_array_state<other, size> state;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
+    typedef detail::lsp_size_array_state<other, count> state;
     typedef detail::sp_array_base<state> base;
-    detail::sp_array_result<other, base> result(allocator, size);
+    detail::sp_array_result<other, base> result(allocator, count);
     base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size, start);
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
     detail::lsp_array_base& local = node->state().base();
     local.set(node);
     result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(), start,
+        &local);
 }
 
 template<class T, class A>
@@ -119,25 +116,19 @@ inline typename enable_if_<is_unbounded_array<T>::value,
 allocate_local_shared(const A& allocator, std::size_t count,
     const typename remove_extent<T>::type& value)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
     typedef detail::lsp_array_state<other> state;
     typedef detail::sp_array_base<state> base;
-    enum {
-        total = detail::sp_array_count<type, scalar>::value
-    };
-    std::size_t size = count * total;
-    detail::sp_array_result<other, base> result(allocator, size);
+    detail::sp_array_result<other, base> result(allocator, count);
     base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size,
-        reinterpret_cast<const scalar*>(&value), total, start);
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
     detail::lsp_array_base& local = node->state().base();
     local.set(node);
     result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(), start,
+        &local);
 }
 
 template<class T, class A>
@@ -146,25 +137,22 @@ inline typename enable_if_<is_bounded_array<T>::value,
 allocate_local_shared(const A& allocator,
     const typename remove_extent<T>::type& value)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
     enum {
-        size = detail::sp_array_count<T, scalar>::value
+        count = extent<T>::value
     };
-    typedef detail::lsp_size_array_state<other, size> state;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
+    typedef detail::lsp_size_array_state<other, count> state;
     typedef detail::sp_array_base<state> base;
-    detail::sp_array_result<other, base> result(allocator, size);
+    detail::sp_array_result<other, base> result(allocator, count);
     base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size,
-        reinterpret_cast<const scalar*>(&value),
-        detail::sp_array_count<type, scalar>::value, start);
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
     detail::lsp_array_base& local = node->state().base();
     local.set(node);
     result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(), start,
+        &local);
 }
 
 template<class T, class A>
@@ -172,22 +160,8 @@ inline typename enable_if_<is_unbounded_array<T>::value,
     local_shared_ptr<T> >::type
 allocate_local_shared_noinit(const A& allocator, std::size_t count)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
-    typedef detail::lsp_array_state<other> state;
-    typedef detail::sp_array_base<state, false> base;
-    std::size_t size = count * detail::sp_array_count<type, scalar>::value;
-    detail::sp_array_result<other, base> result(allocator, size);
-    base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(detail::sp_default(), allocator,
-        size, start);
-    detail::lsp_array_base& local = node->state().base();
-    local.set(node);
-    result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return boost::allocate_local_shared<T>(boost::noinit_adapt(allocator),
+        count);
 }
 
 template<class T, class A>
@@ -195,24 +169,7 @@ inline typename enable_if_<is_bounded_array<T>::value,
     local_shared_ptr<T> >::type
 allocate_local_shared_noinit(const A& allocator)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
-    enum {
-        size = detail::sp_array_count<T, scalar>::value
-    };
-    typedef detail::lsp_size_array_state<other, size> state;
-    typedef detail::sp_array_base<state, false> base;
-    detail::sp_array_result<other, base> result(allocator, size);
-    base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(detail::sp_default(), allocator,
-        size, start);
-    detail::lsp_array_base& local = node->state().base();
-    local.set(node);
-    result.release();
-    return local_shared_ptr<T>(detail::lsp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), &local);
+    return boost::allocate_local_shared<T>(boost::noinit_adapt(allocator));
 }
 
 } /* boost */

include/boost/smart_ptr/allocate_shared_array.hpp

@@ -8,15 +8,14 @@ Distributed under the Boost Software License, Version 1.0.
 #ifndef BOOST_SMART_PTR_ALLOCATE_SHARED_ARRAY_HPP
 #define BOOST_SMART_PTR_ALLOCATE_SHARED_ARRAY_HPP
 
+#include <boost/core/alloc_construct.hpp>
+#include <boost/core/first_scalar.hpp>
 #include <boost/smart_ptr/shared_ptr.hpp>
 #include <boost/type_traits/alignment_of.hpp>
 #include <boost/type_traits/enable_if.hpp>
+#include <boost/type_traits/extent.hpp>
 #include <boost/type_traits/is_bounded_array.hpp>
 #include <boost/type_traits/is_unbounded_array.hpp>
-#include <boost/type_traits/has_trivial_assign.hpp>
-#include <boost/type_traits/has_trivial_constructor.hpp>
-#include <boost/type_traits/has_trivial_destructor.hpp>
-#include <boost/type_traits/remove_all_extents.hpp>
 #include <boost/type_traits/remove_cv.hpp>
 #include <boost/type_traits/remove_extent.hpp>
 #include <boost/type_traits/type_with_alignment.hpp>
@@ -25,15 +24,22 @@ namespace boost {
 namespace detail {
 
 template<class T>
-struct sp_array_scalar {
+struct sp_array_element {
     typedef typename boost::remove_cv<typename
-        boost::remove_all_extents<T>::type>::type type;
+        boost::remove_extent<T>::type>::type type;
 };
 
-template<class T, class U>
+template<class T>
 struct sp_array_count {
     enum {
-        value = sizeof(T) / sizeof(U)
+        value = 1
+    };
+};
+
+template<class T, std::size_t N>
+struct sp_array_count<T[N]> {
+    enum {
+        value = N * sp_array_count<T>::value
     };
 };
 
@@ -70,154 +76,6 @@ sp_objects(std::size_t size) BOOST_SP_NOEXCEPT
     return (size + sizeof(T) - 1) / sizeof(T);
 }
 
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    boost::has_trivial_destructor<T>::value>::type
-sp_array_destroy(A&, T*, std::size_t) BOOST_SP_NOEXCEPT { }
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    !boost::has_trivial_destructor<T>::value>::type
-sp_array_destroy(A&, T* ptr, std::size_t size)
-{
-    while (size > 0) {
-        ptr[--size].~T();
-    }
-}
-
-#if !defined(BOOST_NO_CXX11_ALLOCATOR)
-template<bool E, class A, class T>
-inline typename boost::enable_if_<E>::type
-sp_array_destroy(A& allocator, T* ptr, std::size_t size)
-{
-    while (size > 0) {
-        std::allocator_traits<A>::destroy(allocator, ptr + --size);
-    }
-}
-#endif
-
-template<bool E, class A, class T>
-class sp_destroyer {
-public:
-    sp_destroyer(A& allocator, T* ptr) BOOST_SP_NOEXCEPT
-        : allocator_(allocator),
-          ptr_(ptr),
-          size_(0) { }
-
-    ~sp_destroyer() {
-        sp_array_destroy<E>(allocator_, ptr_, size_);
-    }
-
-    std::size_t& size() BOOST_SP_NOEXCEPT {
-        return size_;
-    }
-
-private:
-    sp_destroyer(const sp_destroyer&);
-    sp_destroyer& operator=(const sp_destroyer&);
-
-    A& allocator_;
-    T* ptr_;
-    std::size_t size_;
-};
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    boost::has_trivial_constructor<T>::value &&
-    boost::has_trivial_assign<T>::value &&
-    boost::has_trivial_destructor<T>::value>::type
-sp_array_construct(A&, T* ptr, std::size_t size)
-{
-    for (std::size_t i = 0; i < size; ++i) {
-        ptr[i] = T();
-    }
-}
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    boost::has_trivial_constructor<T>::value &&
-    boost::has_trivial_assign<T>::value &&
-    boost::has_trivial_destructor<T>::value>::type
-sp_array_construct(A&, T* ptr, std::size_t size, const T* list,
-    std::size_t count)
-{
-    for (std::size_t i = 0; i < size; ++i) {
-        ptr[i] = list[i % count];
-    }
-}
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    !(boost::has_trivial_constructor<T>::value &&
-      boost::has_trivial_assign<T>::value &&
-      boost::has_trivial_destructor<T>::value)>::type
-sp_array_construct(A& none, T* ptr, std::size_t size)
-{
-    sp_destroyer<E, A, T> hold(none, ptr);
-    for (std::size_t& i = hold.size(); i < size; ++i) {
-        ::new(static_cast<void*>(ptr + i)) T();
-    }
-    hold.size() = 0;
-}
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<!E &&
-    !(boost::has_trivial_constructor<T>::value &&
-      boost::has_trivial_assign<T>::value &&
-      boost::has_trivial_destructor<T>::value)>::type
-sp_array_construct(A& none, T* ptr, std::size_t size, const T* list,
-    std::size_t count)
-{
-    sp_destroyer<E, A, T> hold(none, ptr);
-    for (std::size_t& i = hold.size(); i < size; ++i) {
-        ::new(static_cast<void*>(ptr + i)) T(list[i % count]);
-    }
-    hold.size() = 0;
-}
-
-#if !defined(BOOST_NO_CXX11_ALLOCATOR)
-template<bool E, class A, class T>
-inline typename boost::enable_if_<E>::type
-sp_array_construct(A& allocator, T* ptr, std::size_t size)
-{
-    sp_destroyer<E, A, T> hold(allocator, ptr);
-    for (std::size_t& i = hold.size(); i < size; ++i) {
-        std::allocator_traits<A>::construct(allocator, ptr + i);
-    }
-    hold.size() = 0;
-}
-
-template<bool E, class A, class T>
-inline typename boost::enable_if_<E>::type
-sp_array_construct(A& allocator, T* ptr, std::size_t size, const T* list,
-    std::size_t count)
-{
-    sp_destroyer<E, A, T> hold(allocator, ptr);
-    for (std::size_t& i = hold.size(); i < size; ++i) {
-        std::allocator_traits<A>::construct(allocator, ptr + i,
-            list[i % count]);
-    }
-    hold.size() = 0;
-}
-#endif
-
-template<class A, class T>
-inline typename
-    boost::enable_if_<boost::has_trivial_constructor<T>::value>::type
-sp_array_default(A&, T*, std::size_t) BOOST_SP_NOEXCEPT { }
-
-template<class A, class T>
-inline typename
-    boost::enable_if_<!boost::has_trivial_constructor<T>::value>::type
-sp_array_default(A& none, T* ptr, std::size_t size)
-{
-    sp_destroyer<false, A, T> hold(none, ptr);
-    for (std::size_t& i = hold.size(); i < size; ++i) {
-        ::new(static_cast<void*>(ptr + i)) T;
-    }
-    hold.size() = 0;
-}
-
 template<class A>
 class sp_array_state {
 public:
@@ -262,29 +120,6 @@ private:
     A allocator_;
 };
 
-#if !defined(BOOST_NO_CXX11_ALLOCATOR)
-template<class A>
-struct sp_use_construct {
-    enum {
-        value = true
-    };
-};
-
-template<class T>
-struct sp_use_construct<std::allocator<T> > {
-    enum {
-        value = false
-    };
-};
-#else
-template<class>
-struct sp_use_construct {
-    enum {
-        value = false
-    };
-};
-#endif
-
 template<class T, class U>
 struct sp_array_alignment {
     enum {
@@ -300,39 +135,32 @@ struct sp_array_offset {
     };
 };
 
-template<class T, class U>
-struct sp_array_storage {
-    enum {
-        value = sp_array_alignment<T, U>::value
-    };
-    typedef typename boost::type_with_alignment<value>::type type;
-};
-
-template<class T, class U>
+template<class U, class T>
 inline U*
-sp_array_start(void* base) BOOST_SP_NOEXCEPT
+sp_array_start(T* base) BOOST_SP_NOEXCEPT
 {
     enum {
         size = sp_array_offset<T, U>::value
     };
-    return reinterpret_cast<U*>(static_cast<char*>(base) + size);
+    return reinterpret_cast<U*>(reinterpret_cast<char*>(base) + size);
 }
 
 template<class A, class T>
 class sp_array_creator {
-    typedef typename A::value_type scalar;
+    typedef typename A::value_type element;
 
     enum {
-        offset = sp_array_offset<T, scalar>::value
+        offset = sp_array_offset<T, element>::value
     };
 
-    typedef typename sp_array_storage<T, scalar>::type type;
+    typedef typename boost::type_with_alignment<sp_array_alignment<T,
+        element>::value>::type type;
 
 public:
     template<class U>
     sp_array_creator(const U& other, std::size_t size) BOOST_SP_NOEXCEPT
         : other_(other),
-          size_(sp_objects<type>(offset + sizeof(scalar) * size)) { }
+          size_(sp_objects<type>(offset + sizeof(element) * size)) { }
 
     T* create() {
         return reinterpret_cast<T*>(other_.allocate(size_));
@@ -347,9 +175,7 @@ private:
     std::size_t size_;
 };
 
-struct sp_default { };
-
-template<class T, bool E = sp_use_construct<T>::value>
+template<class T>
 class BOOST_SYMBOL_VISIBLE sp_array_base
     : public sp_counted_base {
     typedef typename T::type allocator;
@@ -358,23 +184,22 @@ public:
     typedef typename allocator::value_type type;
 
     template<class A>
-    sp_array_base(const A& other, std::size_t size, type* start)
+    sp_array_base(const A& other, type* start, std::size_t size)
         : state_(other, size) {
-        sp_array_construct<E>(state_.allocator(), start, state_.size());
+        boost::alloc_construct_n(state_.allocator(),
+            boost::first_scalar(start),
+            state_.size() * sp_array_count<type>::value);
     }
 
-    template<class A>
-    sp_array_base(const A& other, std::size_t size, const type* list,
-        std::size_t count, type* start)
+    template<class A, class U>
+    sp_array_base(const A& other, type* start, std::size_t size, const U& list)
         : state_(other, size) {
-        sp_array_construct<E>(state_.allocator(), start, state_.size(), list,
-            count);
-    }
-
-    template<class A>
-    sp_array_base(sp_default, const A& other, std::size_t size, type* start)
-        : state_(other, size) {
-        sp_array_default(state_.allocator(), start, state_.size());
+        enum {
+            count = sp_array_count<type>::value
+        };
+        boost::alloc_construct_n(state_.allocator(),
+            boost::first_scalar(start), state_.size() * count,
+            boost::first_scalar(&list), count);
     }
 
     T& state() BOOST_SP_NOEXCEPT {
@@ -382,8 +207,9 @@ public:
     }
 
     virtual void dispose() BOOST_SP_NOEXCEPT {
-        sp_array_destroy<E>(state_.allocator(),
-            sp_array_start<sp_array_base, type>(this), state_.size());
+        boost::alloc_destroy_n(state_.allocator(),
+            boost::first_scalar(sp_array_start<type>(this)),
+            state_.size() * sp_array_count<type>::value);
     }
 
     virtual void destroy() BOOST_SP_NOEXCEPT {
@@ -423,11 +249,11 @@ public:
         }
     }
 
-    T* get() const {
+    T* get() const BOOST_SP_NOEXCEPT {
         return result_;
     }
 
-    void release() {
+    void release() BOOST_SP_NOEXCEPT {
         result_ = 0;
     }
 
@@ -445,40 +271,37 @@ template<class T, class A>
 inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared(const A& allocator, std::size_t count)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
     typedef detail::sp_array_state<other> state;
     typedef detail::sp_array_base<state> base;
-    std::size_t size = count * detail::sp_array_count<type, scalar>::value;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size, start);
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
     result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
 }
 
 template<class T, class A>
 inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared(const A& allocator)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
     enum {
-        size = detail::sp_array_count<T, scalar>::value
+        count = extent<T>::value
     };
-    typedef detail::sp_size_array_state<other, size> state;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
+    typedef detail::sp_size_array_state<other, extent<T>::value> state;
     typedef detail::sp_array_base<state> base;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size, start);
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
     result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
 }
 
 template<class T, class A>
@@ -486,23 +309,17 @@ inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared(const A& allocator, std::size_t count,
     const typename remove_extent<T>::type& value)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
     typedef detail::sp_array_state<other> state;
     typedef detail::sp_array_base<state> base;
-    enum {
-        total = detail::sp_array_count<type, scalar>::value
-    };
-    std::size_t size = count * total;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size,
-        reinterpret_cast<const scalar*>(&value), total, start);
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
     result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
 }
 
 template<class T, class A>
@@ -510,65 +327,34 @@ inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared(const A& allocator,
     const typename remove_extent<T>::type& value)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
     enum {
-        size = detail::sp_array_count<T, scalar>::value
+        count = extent<T>::value
     };
-    typedef detail::sp_size_array_state<other, size> state;
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename detail::sp_bind_allocator<A, element>::type other;
+    typedef detail::sp_size_array_state<other, extent<T>::value> state;
     typedef detail::sp_array_base<state> base;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(allocator, size,
-        reinterpret_cast<const scalar*>(&value),
-        detail::sp_array_count<type, scalar>::value, start);
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
     result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
 }
 
 template<class T, class A>
 inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared_noinit(const A& allocator, std::size_t count)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
-    typedef detail::sp_array_state<other> state;
-    typedef detail::sp_array_base<state, false> base;
-    std::size_t size = count * detail::sp_array_count<type, scalar>::value;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(detail::sp_default(), allocator,
-        size, start);
-    result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return boost::allocate_shared<T>(boost::noinit_adapt(allocator), count);
 }
 
 template<class T, class A>
 inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 allocate_shared_noinit(const A& allocator)
 {
-    typedef typename remove_extent<T>::type type;
-    typedef typename detail::sp_array_scalar<T>::type scalar;
-    typedef typename detail::sp_bind_allocator<A, scalar>::type other;
-    enum {
-        size = detail::sp_array_count<T, scalar>::value
-    };
-    typedef detail::sp_size_array_state<other, size> state;
-    typedef detail::sp_array_base<state, false> base;
-    detail::sp_array_result<other, base> result(allocator, size);
-    detail::sp_counted_base* node = result.get();
-    scalar* start = detail::sp_array_start<base, scalar>(node);
-    ::new(static_cast<void*>(node)) base(detail::sp_default(), allocator,
-        size, start);
-    result.release();
-    return shared_ptr<T>(detail::sp_internal_constructor_tag(),
-        reinterpret_cast<type*>(start), detail::shared_count(node));
+    return boost::allocate_shared<T>(boost::noinit_adapt(allocator));
 }
 
 } /* boost */

include/boost/smart_ptr/detail/atomic_count_std_atomic.hpp

@@ -26,7 +26,7 @@ class atomic_count
 {
 public:
 
-    explicit atomic_count( long v ): value_( v )
+    explicit atomic_count( long v ): value_( static_cast< std::int_least32_t >( v ) )
     {
     }
 

include/boost/smart_ptr/enable_shared_from.hpp

@@ -0,0 +1,37 @@
+#ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_HPP_INCLUDED
+#define BOOST_SMART_PTR_ENABLE_SHARED_FROM_HPP_INCLUDED
+
+//  enable_shared_from.hpp
+//
+//  Copyright 2019 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
+//
+//  See http://www.boost.org/libs/smart_ptr/ for documentation.
+
+#include <boost/smart_ptr/enable_shared_from_this.hpp>
+#include <boost/smart_ptr/detail/sp_noexcept.hpp>
+
+namespace boost
+{
+
+class enable_shared_from: public enable_shared_from_this<enable_shared_from>
+{
+};
+
+
+template<class T> shared_ptr<T> shared_from( T * p )
+{
+    return shared_ptr<T>( p->enable_shared_from::shared_from_this(), p );
+}
+
+template<class T> weak_ptr<T> weak_from( T * p ) BOOST_SP_NOEXCEPT
+{
+    return weak_ptr<T>( p->enable_shared_from::weak_from_this(), p );
+}
+
+} // namespace boost
+
+#endif  // #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_HPP_INCLUDED

include/boost/smart_ptr/make_local_shared_array.hpp

@@ -9,6 +9,7 @@ Distributed under the Boost Software License, Version 1.0.
 #ifndef BOOST_SMART_PTR_MAKE_LOCAL_SHARED_ARRAY_HPP
 #define BOOST_SMART_PTR_MAKE_LOCAL_SHARED_ARRAY_HPP
 
+#include <boost/core/default_allocator.hpp>
 #include <boost/smart_ptr/allocate_local_shared_array.hpp>
 
 namespace boost {
@@ -18,8 +19,8 @@ inline typename enable_if_<is_bounded_array<T>::value,
     local_shared_ptr<T> >::type
 make_local_shared()
 {
-    return boost::allocate_local_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>());
+    return boost::allocate_local_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>());
 }
 
 template<class T>
@@ -27,8 +28,8 @@ inline typename enable_if_<is_bounded_array<T>::value,
     local_shared_ptr<T> >::type
 make_local_shared(const typename remove_extent<T>::type& value)
 {
-    return boost::allocate_local_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), value);
+    return boost::allocate_local_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), value);
 }
 
 template<class T>
@@ -36,8 +37,8 @@ inline typename enable_if_<is_unbounded_array<T>::value,
     local_shared_ptr<T> >::type
 make_local_shared(std::size_t size)
 {
-    return boost::allocate_local_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size);
+    return boost::allocate_local_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), size);
 }
 
 template<class T>
@@ -46,8 +47,8 @@ inline typename enable_if_<is_unbounded_array<T>::value,
 make_local_shared(std::size_t size,
     const typename remove_extent<T>::type& value)
 {
-    return boost::allocate_local_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size, value);
+    return boost::allocate_local_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), size, value);
 }
 
 template<class T>
@@ -55,8 +56,8 @@ inline typename enable_if_<is_bounded_array<T>::value,
     local_shared_ptr<T> >::type
 make_local_shared_noinit()
 {
-    return boost::allocate_local_shared_noinit<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>());
+    return boost::allocate_local_shared_noinit<T>(boost::
+        default_allocator<typename detail::sp_array_element<T>::type>());
 }
 
 template<class T>
@@ -64,8 +65,8 @@ inline typename enable_if_<is_unbounded_array<T>::value,
     local_shared_ptr<T> >::type
 make_local_shared_noinit(std::size_t size)
 {
-    return boost::allocate_local_shared_noinit<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size);
+    return boost::allocate_local_shared_noinit<T>(boost::
+        default_allocator<typename detail::sp_array_element<T>::type>(), size);
 }
 
 } /* boost */

include/boost/smart_ptr/make_shared_array.hpp

@@ -8,6 +8,7 @@ Distributed under the Boost Software License, Version 1.0.
 #ifndef BOOST_SMART_PTR_MAKE_SHARED_ARRAY_HPP
 #define BOOST_SMART_PTR_MAKE_SHARED_ARRAY_HPP
 
+#include <boost/core/default_allocator.hpp>
 #include <boost/smart_ptr/allocate_shared_array.hpp>
 
 namespace boost {
@@ -16,48 +17,48 @@ template<class T>
 inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 make_shared()
 {
-    return boost::allocate_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>());
+    return boost::allocate_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>());
 }
 
 template<class T>
 inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 make_shared(const typename remove_extent<T>::type& value)
 {
-    return boost::allocate_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), value);
+    return boost::allocate_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), value);
 }
 
 template<class T>
 inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 make_shared(std::size_t size)
 {
-    return boost::allocate_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size);
+    return boost::allocate_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), size);
 }
 
 template<class T>
 inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 make_shared(std::size_t size, const typename remove_extent<T>::type& value)
 {
-    return boost::allocate_shared<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size, value);
+    return boost::allocate_shared<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), size, value);
 }
 
 template<class T>
 inline typename enable_if_<is_bounded_array<T>::value, shared_ptr<T> >::type
 make_shared_noinit()
 {
-    return boost::allocate_shared_noinit<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>());
+    return boost::allocate_shared_noinit<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>());
 }
 
 template<class T>
 inline typename enable_if_<is_unbounded_array<T>::value, shared_ptr<T> >::type
 make_shared_noinit(std::size_t size)
 {
-    return boost::allocate_shared_noinit<T>(std::allocator<typename
-        detail::sp_array_scalar<T>::type>(), size);
+    return boost::allocate_shared_noinit<T>(boost::default_allocator<typename
+        detail::sp_array_element<T>::type>(), size);
 }
 
 } /* boost */

test/Jamfile

@@ -315,3 +315,7 @@ run sp_typeinfo_test.cpp : : : <rtti>off : sp_typeinfo_test_no_rtti ;
 run get_deleter_test.cpp : : : <rtti>off <toolset>gcc-4.4.7,<cxxstd>0x:<build>no : get_deleter_test_no_rtti ;
 run get_deleter_test2.cpp : : : <rtti>off <toolset>gcc-4.4.7,<cxxstd>0x:<build>no : get_deleter_test2_no_rtti ;
 run get_deleter_test3.cpp : : : <rtti>off <toolset>gcc-4.4.7,<cxxstd>0x:<build>no : get_deleter_test3_no_rtti ;
+
+run shared_from_test.cpp ;
+run weak_from_test.cpp ;
+run weak_from_test2.cpp ;

test/shared_from_raw_test.cpp

@@ -9,6 +9,10 @@
 //  http://www.boost.org/LICENSE_1_0.txt
 //
 
+#if defined(__GNUC__) && __GNUC__ > 4
+# pragma GCC diagnostic ignored "-Wdelete-non-virtual-dtor"
+#endif
+
 #include <boost/smart_ptr/enable_shared_from_raw.hpp>
 #include <boost/shared_ptr.hpp>
 

test/shared_from_test.cpp

@@ -0,0 +1,102 @@
+
+// shared_from_test.cpp
+//
+// Copyright 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/smart_ptr/enable_shared_from.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+//
+
+class X
+{
+private:
+
+    int m_;
+
+public:
+
+    X(): m_() {}
+};
+
+class Y: public boost::enable_shared_from
+{
+};
+
+class Z: public X, public Y
+{
+public:
+
+    boost::shared_ptr<Z> shared_from_this()
+    {
+        return boost::shared_from( this );
+    }
+};
+
+void null_deleter( void const* )
+{
+}
+
+int main()
+{
+    boost::shared_ptr<Z> p( new Z );
+
+    try
+    {
+        boost::shared_ptr<Z> q = p->shared_from_this();
+
+        BOOST_TEST_EQ( p, q );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+    catch( boost::bad_weak_ptr const & )
+    {
+        BOOST_ERROR( "p->shared_from_this() failed" );
+    }
+
+    Z v2( *p );
+
+    try
+    {
+        boost::shared_ptr<Z> q = v2.shared_from_this();
+        BOOST_ERROR( "v2.shared_from_this() failed to throw" );
+    }
+    catch( boost::bad_weak_ptr const & )
+    {
+    }
+
+    *p = Z();
+
+    try
+    {
+        boost::shared_ptr<Z> q = p->shared_from_this();
+
+        BOOST_TEST_EQ( p, q );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+    catch( boost::bad_weak_ptr const & )
+    {
+        BOOST_ERROR( "p->shared_from_this() threw bad_weak_ptr after *p = Z()" );
+    }
+
+    {
+        boost::shared_ptr<Z> p2( p.get(), null_deleter );
+    }
+
+    try
+    {
+        boost::shared_ptr<Z> q = p->shared_from_this();
+
+        BOOST_TEST_EQ( p, q );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+    catch( boost::bad_weak_ptr const& )
+    {
+        BOOST_ERROR( "p->shared_from_this() failed" );
+    }
+
+    return boost::report_errors();
+}

test/shared_from_this_test.cpp

@@ -7,6 +7,10 @@
 #pragma warning(disable: 4514)  // unreferenced inline removed
 #endif
 
+#if defined(__GNUC__) && __GNUC__ > 4
+# pragma GCC diagnostic ignored "-Wdelete-non-virtual-dtor"
+#endif
+
 //
 //  shared_from_this_test.cpp
 //

test/shared_ptr_basic_test.cpp

@@ -14,6 +14,10 @@
 
 #endif
 
+#if defined(__GNUC__) && __GNUC__ > 4
+# pragma GCC diagnostic ignored "-Wdelete-non-virtual-dtor"
+#endif
+
 //
 //  shared_ptr_basic_test.cpp
 //

test/shared_ptr_test.cpp

@@ -14,6 +14,10 @@
 
 #endif
 
+#if defined(__GNUC__) && __GNUC__ > 4
+# pragma GCC diagnostic ignored "-Wdelete-non-virtual-dtor"
+#endif
+
 //
 //  shared_ptr_test.cpp
 //

test/weak_from_test.cpp

@@ -0,0 +1,97 @@
+
+// weak_from_test.cpp
+//
+// Copyright 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/smart_ptr/enable_shared_from.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+//
+
+class X
+{
+private:
+
+    int m_;
+
+public:
+
+    X(): m_() {}
+};
+
+class Y: public boost::enable_shared_from
+{
+};
+
+class Z: public X, public Y
+{
+public:
+
+    boost::weak_ptr<Z> weak_from_this()
+    {
+        return boost::weak_from( this );
+    }
+};
+
+void null_deleter( void const* )
+{
+}
+
+int main()
+{
+    boost::shared_ptr<Z> sp( new Z );
+    boost::weak_ptr<Z> p( sp );
+
+    {
+        boost::weak_ptr<Z> q = sp->weak_from_this();
+
+        BOOST_TEST_EQ( p.lock(), q.lock() );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+
+    Z v2( *sp );
+
+    {
+        boost::weak_ptr<Z> q = v2.weak_from_this();
+        BOOST_TEST( q.expired() );
+    }
+
+    *sp = Z();
+
+    {
+        boost::weak_ptr<Z> q = sp->weak_from_this();
+
+        BOOST_TEST_EQ( p.lock(), q.lock() );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+
+    {
+        boost::shared_ptr<Z> sp2( sp.get(), null_deleter );
+    }
+
+    {
+        boost::weak_ptr<Z> q = sp->weak_from_this();
+
+        BOOST_TEST_EQ( p.lock(), q.lock() );
+        BOOST_TEST( !( p < q ) && !( q < p ) );
+    }
+
+    {
+        boost::weak_ptr<Z> p2 = sp->weak_from_this();
+
+        BOOST_TEST( !p.expired() );
+        BOOST_TEST( !p2.expired() );
+
+        sp.reset();
+
+        BOOST_TEST( p.expired() );
+        BOOST_TEST( p2.expired() );
+    }
+
+    return boost::report_errors();
+}

test/weak_from_test2.cpp

@@ -0,0 +1,57 @@
+
+//  weak_from_test2.cpp
+//
+//  Tests weak_from in a destructor
+//
+//  Copyright 2014, 2015, 2019 Peter Dimov
+//
+//  Distributed under the Boost Software License, Version 1.0.
+//  http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/smart_ptr/enable_shared_from.hpp>
+#include <boost/weak_ptr.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+class X: public boost::enable_shared_from
+{
+private:
+
+    boost::weak_ptr<X> px_;
+
+public:
+
+    X()
+    {
+        boost::weak_ptr<X> p1 = weak_from( this );
+        BOOST_TEST( p1._empty() );
+        BOOST_TEST( p1.expired() );
+    }
+
+    void check()
+    {
+        boost::weak_ptr<X> p2 = weak_from( this );
+        BOOST_TEST( !p2.expired() );
+
+        BOOST_TEST( p2.lock().get() == this );
+
+        px_ = p2;
+    }
+
+    ~X()
+    {
+        boost::weak_ptr<X> p3 = weak_from( this );
+        BOOST_TEST( p3.expired() );
+
+        BOOST_TEST( !(px_ < p3) && !(p3 < px_) );
+    }
+};
+
+int main()
+{
+    {
+        boost::shared_ptr< X > px( new X );
+        px->check();
+    }
+
+    return boost::report_errors();
+}

test/weak_from_this_test.cpp

@@ -39,7 +39,7 @@ void test()
 
     *p = V();
 
-    boost::weak_ptr<V> q4 = p->shared_from_this();
+    boost::weak_ptr<V> q4 = p->weak_from_this();
     BOOST_TEST( !q4.expired() );
     BOOST_TEST( !(q < q4) && !(q4 < q) );
     BOOST_TEST( !(q2 < q4) && !(q4 < q2) );