Rename BOOST_CORE_SNPRINTF to BOOST_CORE_DETAIL_SNPRINTF

Jamfile parser created incorrect test for fclose_deleter_test,
which resulted in a compiler error. Prevent the parser from creating
the test target by reformatting the Jamfile and create a CMake
target with proper dependencies.

.github/workflows/ci.yml

@@ -1,5 +1,5 @@
 # Copyright 2020-2021 Peter Dimov
-# Copyright 2021 Andrey Semashev
+# Copyright 2021-2022 Andrey Semashev
 #
 # 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)
@@ -32,7 +32,7 @@ jobs:
           # Linux, gcc
           - toolset: gcc-4.4
             cxxstd: "98,0x"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - g++-4.4
@@ -40,7 +40,7 @@ jobs:
               - "ppa:ubuntu-toolchain-r/test"
           - toolset: gcc-4.6
             cxxstd: "03,0x"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - g++-4.6
@@ -48,45 +48,49 @@ jobs:
               - "ppa:ubuntu-toolchain-r/test"
           - toolset: gcc-4.7
             cxxstd: "03,11"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - g++-4.7
           - toolset: gcc-4.8
             cxxstd: "03,11"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - g++-4.8
           - toolset: gcc-4.9
             cxxstd: "03,11"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - g++-4.9
           - toolset: gcc-5
             cxxstd: "03,11,14,1z"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - g++-5
           - toolset: gcc-6
             cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - g++-6
           - toolset: gcc-7
             cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - g++-7
           - toolset: gcc-8
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - g++-8
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
+            os: ubuntu-20.04
             install:
               - g++-9
           - toolset: gcc-10
@@ -95,18 +99,18 @@ jobs:
             install:
               - g++-10
           - toolset: gcc-11
-            cxxstd: "03,11,14,17,20"
-            os: ubuntu-20.04
+            cxxstd: "03,11,14,17,20,23"
+            os: ubuntu-22.04
             install:
               - g++-11
           - toolset: gcc-12
-            cxxstd: "03,11,14,17,20"
+            cxxstd: "03,11,14,17,20,23"
             os: ubuntu-22.04
             install:
               - g++-12
           - name: UBSAN
             toolset: gcc-12
-            cxxstd: "03,11,14,17,20"
+            cxxstd: "03,11,14,17,20,23"
             ubsan: 1
             os: ubuntu-22.04
             install:
@@ -116,66 +120,72 @@ jobs:
           - toolset: clang
             compiler: clang++-3.5
             cxxstd: "03,11"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - clang-3.5
           - toolset: clang
             compiler: clang++-3.6
             cxxstd: "03,11,14"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - clang-3.6
           - toolset: clang
             compiler: clang++-3.7
             cxxstd: "03,11,14"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - clang-3.7
           - toolset: clang
             compiler: clang++-3.8
             cxxstd: "03,11,14"
-            os: ubuntu-20.04
+            os: ubuntu-latest
             container: ubuntu:16.04
             install:
               - clang-3.8
           - toolset: clang
             compiler: clang++-3.9
             cxxstd: "03,11,14"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-3.9
           - toolset: clang
             compiler: clang++-4.0
             cxxstd: "03,11,14"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-4.0
           - toolset: clang
             compiler: clang++-5.0
             cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-5.0
           - toolset: clang
             compiler: clang++-6.0
             cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-6.0
           - toolset: clang
             compiler: clang++-7
             cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-7
           # Note: clang-8 does not fully support C++20, so it is not compatible with libstdc++-8 in this mode
           - toolset: clang
             compiler: clang++-8
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
+            os: ubuntu-latest
+            container: ubuntu:18.04
             install:
               - clang-8
               - g++-7
@@ -195,67 +205,67 @@ jobs:
           - toolset: clang
             compiler: clang++-11
             cxxstd: "03,11,14,17,20"
-            os: ubuntu-20.04
+            os: ubuntu-22.04
             install:
               - clang-11
           - toolset: clang
             compiler: clang++-12
-            cxxstd: "03,11,14,17,20"
-            os: ubuntu-20.04
+            cxxstd: "03,11,14,17,20,2b"
+            os: ubuntu-22.04
             install:
               - clang-12
-          - toolset: clang
-            compiler: clang++-12
-            cxxstd: "03,11,14,17,20"
-            cxxflags: -stdlib=libc++
-            linkflags: -stdlib=libc++
-            os: ubuntu-20.04
-            install:
-              - clang-12
-              - libc++-12-dev
-              - libc++abi-12-dev
           - toolset: clang
             compiler: clang++-13
-            cxxstd: "03,11,14,17,20"
+            cxxstd: "03,11,14,17,20,2b"
             os: ubuntu-22.04
             install:
               - clang-13
           - toolset: clang
             compiler: clang++-14
-            cxxstd: "03,11,14,17,20"
+            cxxstd: "03,11,14,17,20,2b"
             os: ubuntu-22.04
             install:
               - clang-14
           - toolset: clang
-            compiler: clang++-13
-            cxxstd: "03,11,14,17,20"
-            os: ubuntu-20.04
+            compiler: clang++-15
+            cxxstd: "03,11,14,17,20,2b"
+            os: ubuntu-22.04
             install:
-              - clang-13
-              - libc++-13-dev
-              - libc++abi-13-dev
+              - clang-15
             sources:
-              - "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-13 main"
+              - "deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-15 main"
+            source_keys:
+              - "https://apt.llvm.org/llvm-snapshot.gpg.key"
+          - toolset: clang
+            compiler: clang++-15
+            cxxstd: "03,11,14,17,20,2b"
+            os: ubuntu-22.04
+            install:
+              - clang-15
+              - libc++-15-dev
+              - libc++abi-15-dev
+            sources:
+              - "deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-15 main"
             source_keys:
               - "https://apt.llvm.org/llvm-snapshot.gpg.key"
             cxxflags: -stdlib=libc++
             linkflags: -stdlib=libc++
           - name: UBSAN
             toolset: clang
-            compiler: clang++-12
-            cxxstd: "03,11,14,17,20"
+            compiler: clang++-14
+            cxxstd: "03,11,14,17,20,2b"
             cxxflags: -stdlib=libc++
             linkflags: -stdlib=libc++
             ubsan: 1
-            os: ubuntu-20.04
+            os: ubuntu-22.04
             install:
-              - clang-12
-              - libc++-12-dev
-              - libc++abi-12-dev
+              - clang-14
+              - libc++-14-dev
+              - libc++abi-14-dev
 
           - toolset: clang
             cxxstd: "03,11,14,17,2a"
-            os: macos-10.15
+            os: macos-11
 
     timeout-minutes: 120
     runs-on: ${{matrix.os}}
@@ -275,12 +285,18 @@ jobs:
                 if [ -f "/etc/debian_version" ]
                 then
                     apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
-                    apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common tzdata wget curl apt-transport-https ca-certificates make build-essential g++ python python3 perl git cmake
+                    if [ "$(apt-cache search "^python-is-python3$" | wc -l)" -ne 0 ]
+                    then
+                        PYTHON_PACKAGE="python-is-python3"
+                    else
+                        PYTHON_PACKAGE="python"
+                    fi
+                    apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common tzdata wget curl apt-transport-https ca-certificates make build-essential g++ $PYTHON_PACKAGE python3 perl git cmake
                 fi
             fi
             git config --global pack.threads 0
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
         if: matrix.install
@@ -367,6 +383,7 @@ jobs:
             BUILD_JOBS=$((nproc || sysctl -n hw.ncpu) 2> /dev/null)
             echo "BUILD_JOBS=$BUILD_JOBS" >> $GITHUB_ENV
             echo "CMAKE_BUILD_PARALLEL_LEVEL=$BUILD_JOBS" >> $GITHUB_ENV
+            DEPINST_ARGS=()
             GIT_VERSION="$(git --version | sed -e 's/git version //')"
             GIT_HAS_JOBS=1
             if [ -f "/etc/debian_version" ]
@@ -393,25 +410,16 @@ jobs:
             fi
             if [ "$GIT_HAS_JOBS" -ne 0 ]
             then
-                GIT_ARGS="--jobs $GIT_FETCH_JOBS"
+                DEPINST_ARGS+=("--git_args" "--jobs $GIT_FETCH_JOBS")
             fi
             cd ..
             git clone -b "$BOOST_BRANCH" --depth 1 "https://github.com/boostorg/boost.git" "boost-root"
             cd boost-root
             mkdir -p libs/$LIBRARY
             cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
-            git submodule init tools/boost_install
-            git submodule init libs/headers
-            git submodule init tools/build
-            git submodule init tools/cmake
-            git submodule init libs/assert
-            git submodule init libs/config
-            git submodule init libs/static_assert
-            git submodule init libs/throw_exception
-            git submodule init libs/type_traits
-            git submodule init libs/utility
-            git submodule init libs/io
-            git submodule update $GIT_ARGS
+            git submodule update --init tools/boostdep
+            DEPINST_ARGS+=("$LIBRARY")
+            python tools/boostdep/depinst/depinst.py "${DEPINST_ARGS[@]}"
             ./bootstrap.sh
             ./b2 headers
             if [ -n "${{matrix.compiler}}" -o -n "$GCC_TOOLCHAIN_ROOT" ]
@@ -484,7 +492,7 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Setup Boost
         shell: cmd
@@ -503,18 +511,8 @@ jobs:
             git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
             cd boost-root
             xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
-            git submodule init tools/boost_install
-            git submodule init libs/headers
-            git submodule init tools/build
-            git submodule init tools/cmake
-            git submodule init libs/assert
-            git submodule init libs/config
-            git submodule init libs/static_assert
-            git submodule init libs/throw_exception
-            git submodule init libs/type_traits
-            git submodule init libs/utility
-            git submodule init libs/io
-            git submodule update --jobs %GIT_FETCH_JOBS%
+            git submodule update --init tools/boostdep
+            python tools/boostdep/depinst/depinst.py --git_args "--jobs %GIT_FETCH_JOBS%" %LIBRARY%
             cmd /c bootstrap
             b2 -d0 headers
 
@@ -529,15 +527,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
         if: matrix.install
@@ -554,21 +551,21 @@ jobs:
           REF=${GITHUB_BASE_REF:-$GITHUB_REF}
           REF=${REF#refs/heads/}
           echo REF: $REF
-          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
+          BOOST_BRANCH=develop && [ "$REF" = "master" ] && BOOST_BRANCH=master || true
           echo BOOST_BRANCH: $BOOST_BRANCH
           cd ..
           git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
           cd boost-root
           cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
           git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs $GIT_FETCH_JOBS" $LIBRARY
 
       - name: Use library with add_subdirectory
         run: |
           cd ../boost-root/libs/$LIBRARY/test/cmake_subdir_test
           mkdir __build__ && cd __build__
           cmake ..
-          cmake --build .
+          cmake --build . -- -j $BUILD_JOBS
           ctest --output-on-failure --no-tests=error
 
   posix-cmake-install:
@@ -576,15 +573,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
         if: matrix.install
@@ -601,14 +597,14 @@ jobs:
           REF=${GITHUB_BASE_REF:-$GITHUB_REF}
           REF=${REF#refs/heads/}
           echo REF: $REF
-          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
+          BOOST_BRANCH=develop && [ "$REF" = "master" ] && BOOST_BRANCH=master || true
           echo BOOST_BRANCH: $BOOST_BRANCH
           cd ..
           git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
           cd boost-root
           cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
           git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs $GIT_FETCH_JOBS" $LIBRARY
 
       - name: Configure
         run: |
@@ -619,13 +615,13 @@ jobs:
       - name: Install
         run: |
           cd ../boost-root/__build__
-          cmake --build . --target install
+          cmake --build . --target install -- -j $BUILD_JOBS
 
       - name: Use the installed library
         run: |
           cd ../boost-root/libs/$LIBRARY/test/cmake_install_test && mkdir __build__ && cd __build__
           cmake -DCMAKE_INSTALL_PREFIX=~/.local ..
-          cmake --build .
+          cmake --build . -- -j $BUILD_JOBS
           ctest --output-on-failure --no-tests=error
 
   posix-cmake-test:
@@ -633,15 +629,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
         if: matrix.install
@@ -658,14 +653,14 @@ jobs:
           REF=${GITHUB_BASE_REF:-$GITHUB_REF}
           REF=${REF#refs/heads/}
           echo REF: $REF
-          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
+          BOOST_BRANCH=develop && [ "$REF" = "master" ] && BOOST_BRANCH=master || true
           echo BOOST_BRANCH: $BOOST_BRANCH
           cd ..
           git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
           cd boost-root
           cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
           git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs $GIT_FETCH_JOBS" $LIBRARY
 
       - name: Configure
         run: |
@@ -676,7 +671,7 @@ jobs:
       - name: Build tests
         run: |
           cd ../boost-root/__build__
-          cmake --build . --target tests
+          cmake --build . --target tests -- -j $BUILD_JOBS
 
       - name: Run tests
         run: |

appveyor.yml

@@ -60,24 +60,15 @@ environment:
       CXXSTD: 03,11,14,1z
 
 install:
+  - set GIT_FETCH_JOBS=8
   - set BOOST_BRANCH=develop
   - if "%APPVEYOR_REPO_BRANCH%" == "master" set BOOST_BRANCH=master
   - cd ..
   - git clone -b %BOOST_BRANCH% https://github.com/boostorg/boost.git boost-root
   - cd boost-root
-  - git submodule init libs/headers
-  - git submodule init libs/assert
-  - git submodule init libs/config
-  - git submodule init libs/predef
-  - git submodule init libs/static_assert
-  - git submodule init libs/throw_exception
-  - git submodule init libs/type_traits
-  - git submodule init libs/utility
-  - git submodule init libs/io
-  - git submodule init tools/build
-  - git submodule init tools/boost_install
-  - git submodule update --jobs 4
+  - git submodule update --init tools/boostdep
   - xcopy /s /e /q %APPVEYOR_BUILD_FOLDER% libs\core\
+  - python tools/boostdep/depinst/depinst.py --git_args "--jobs %GIT_FETCH_JOBS%" core
   - cmd /c bootstrap
   - b2 headers
 

doc/allocator_access.qbk

@@ -293,7 +293,7 @@ returns `a`.]]]
 
 [endsect]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 Glen Fernandes implemented the allocator access utilities.
 

doc/bit.qbk

@@ -45,7 +45,7 @@ template<class T>
 constexpr T bit_floor(T x) noexcept;
 
 template<class T>
-constexpr T bit_width(T x) noexcept;
+constexpr int bit_width(T x) noexcept;
 
 // Rotating
 
@@ -119,7 +119,7 @@ constant expression context.
 * *Requires:* `T` must be an unsigned integer type.
 * *Returns:* If `x == 0`, 0; otherwise the maximal value `y` such that `has_single_bit(y)` is `true` and `y <= x`.
 
-`template<class T> constexpr T bit_width(T x) noexcept;`
+`template<class T> constexpr int bit_width(T x) noexcept;`
 
 * *Requires:* `T` must be an unsigned integer type.
 * *Returns:* If `x == 0`, 0; otherwise one plus the base-2 logarithm of `x`, with any fractional part discarded.

doc/changes.qbk

@@ -6,11 +6,39 @@
 
 [section Revision History]
 
+[section Changes in 1.81.0]
+
+* [link core.empty_value `empty_value`] members are now marked as `constexpr`.
+* Added [link core.fclose_deleter `fclose_deleter`], a deleter that calls `std::fclose` on a pointer to `std::FILE`.
+* Bit manipulation utilities in [link core.bit `boost/core/bit.hpp`] now explicitly require unsigned integers on input.
+  ([@https://github.com/boostorg/core/issues/129 #129])
+* `bit_width` now returns `int` instead of a value of the input argument type. This follows the
+  resolution of [@https://cplusplus.github.io/LWG/issue3656 LWG3656].
+
+[endsect]
+
+[section Changes in 1.80.0]
+
+* In [link core.allocator_access `boost/core/allocator_access.hpp`], added detection of `construct` and `destroy`
+  members of an allocator.
+* `boost/core/alloc_construct.hpp` header is now deprecated and will be removed in a future release. Its functionality
+  was moved to [link core.allocator_access `boost/core/allocator_access.hpp`]. In particular, new methods
+  `allocator_construct_n` and `allocator_destroy_n` were added for allocating and destroying arrays.
+* Worked around MSVC bug that failed to compile [link core.span `span`] in C++17 mode when Boost.Range headers were included.
+  ([@https://github.com/boostorg/core/issues/105 #105], [@https://github.com/boostorg/core/pull/115 PR#115])
+* Added support for 128-bit integer types in [link core.type_name `type_name`].
+* In [link core.pointer_traits `pointer_traits`], pointer rebinding now supports C++03 compilers.
+
+[endsect]
+
 [section Changes in 1.79.0]
 
 * Added `boost::allocator_traits`, an implementation of `std::allocator_traits`.
 * Made `boost::pointer_traits` SFINAE friendly.
-* `boost/iterator.hpp` is deprecated and will be removed in a future release. The header defines `boost::iterator` template, which is equivalent to `std::iterator` in `<iterator>` header. However, since `std::iterator` is itself deprecated in C++17, users are advised to remove `boost::iterator` or `std::iterator` use from their code.
+* `boost/iterator.hpp` is deprecated and will be removed in a future release. The header defines the
+  `boost::iterator` template, which is equivalent to `std::iterator` in the `<iterator>` header. However,
+  since `std::iterator` is itself deprecated in C++17, users are advised to remove the use of `boost::iterator`
+  or `std::iterator` from their code.
 * Added `boost::core::verbose_terminate_handler`, a utility function intended
   to be passed to `std::set_terminate` that prints information about the
   uncaught exception to `stderr`.

doc/core.qbk

@@ -60,6 +60,7 @@ criteria for inclusion is that the utility component be:
 [include noinit_adaptor.qbk]
 [include noncopyable.qbk]
 [include null_deleter.qbk]
+[include fclose_deleter.qbk]
 [include nvp.qbk]
 [include pointer_traits.qbk]
 [include quick_exit.qbk]

doc/demangle.qbk

@@ -125,7 +125,7 @@ return `nullptr` if demangling failed.
 
 [endsect]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 The implementation of `core::demangle` was taken from
 `boost/exception/detail/type_info.hpp`, which in turn was adapted

doc/empty_value.qbk

@@ -90,11 +90,11 @@ public:
     empty_value() = default;
 
     template<class... Args>
-    empty_value(empty_init_t, Args&&... args);
+    constepxr empty_value(empty_init_t, Args&&... args);
 
-    const T& get() const noexcept;
+    constepxr const T& get() const noexcept;
 
-    T& get() noexcept;
+    constepxr T& get() noexcept;
 };
 
 inline constexpr empty_init_t empty_init{ };
@@ -121,8 +121,9 @@ inline constexpr empty_init_t empty_init{ };
 [section Constructors]
 
 [variablelist
-[[`empty_value() = default;`][Default initialize the value]]
-[[`template<class... Args> empty_value(empty_init_t, Args&&... args);`]
+[[`constepxr empty_value() = default;`][Default initialize the value]]
+[[`template<class... Args>
+constepxr empty_value(empty_init_t, Args&&... args);`]
 [Initialize the value with `std::forward<Args>(args)...`]]]
 
 [endsect]
@@ -130,8 +131,8 @@ inline constexpr empty_init_t empty_init{ };
 [section Member functions]
 
 [variablelist
-[[`const T& get() const noexcept;`][Returns the value]]
-[[`T& get() noexcept;`][Returns the value]]]
+[[`constepxr const T& get() const noexcept;`][Returns the value]]
+[[`constepxr T& get() noexcept;`][Returns the value]]]
 
 [endsect]
 

doc/enable_if.qbk

@@ -304,8 +304,8 @@ depends on the template arguments of the class. Note that
 again, the second argument to `enable_if` is not needed; the
 default (`void`) is the correct value.
 
-The `enable_if_has_type` template is usable this scenario but instead of
-using a type traits to enable or disable a specialization, it use a
+The `enable_if_has_type` template is usable in this scenario but instead of
+using a type trait to enable or disable a specialization, it uses a
 SFINAE context to check for the existence of a dependent type inside
 its parameter. For example, the following structure extracts a dependent
 `value_type` from T if and only if `T::value_type` exists.

doc/fclose_deleter.qbk

@@ -0,0 +1,34 @@
+[/
+ / Copyright (c) 2022 Andrey Semashev
+ /
+ / 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)
+ /]
+
+[section:fclose_deleter fclose_deleter]
+
+[simplesect Authors]
+
+* Andrey Semashev
+
+[endsimplesect]
+
+[section Header <boost/core/fclose_deleter.hpp>]
+
+The header `<boost/core/fclose_deleter.hpp>` defines the `boost::fclose_deleter` function object,
+which can be used as a deleter with smart pointers such as `unique_ptr` or `shared_ptr` pointing to `std::FILE`.
+structures returned by `std::fopen` calls. The deleter calls `std::fclose` on the passed pointer, causing
+the file stream to be flushed and closed.
+
+[section Example]
+``
+std::unique_ptr< std::FILE, boost::fclose_deleter > make_file(const char* filename, const char* open_mode)
+{
+    return { std::fopen(filename, open_mode) };
+}
+``
+[endsect]
+
+[endsect]
+
+[endsect]

doc/ignore_unused.qbk

@@ -51,7 +51,7 @@ int fun( int foo, int bar )
 
 [endsect]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 `boost::ignore_unused()` was contributed by Adam Wulkiewicz.
 

doc/pointer_traits.qbk

@@ -124,7 +124,7 @@ also not defined (`pointer_traits` is SFINAE-friendly).
 [[`static pointer pointer_traits::pointer_to(element_type& v);`]
 [[variablelist
 [[Remark]
-[If `element_type` is a void type, or if `T::pointer_to(v)` is not well formed,
+[If `element_type` is a void type, or if `T::pointer_to(v)` is not well-formed,
   this member is not defined.]]
 [[Returns]
 [A pointer to `v` obtained by calling `T::pointer_to(v)`.]]]]]
@@ -165,7 +165,7 @@ also not defined (`pointer_traits` is SFINAE-friendly).
 
 [endsect]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 Glen Fernandes implemented `pointer_traits` and `to_address` with reviews and
 guidance from Peter Dimov.

doc/ref.qbk

@@ -68,7 +68,7 @@ The type-expression `boost::unwrap_reference<T>::type` is
 
 [xinclude ref_reference.xml]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 `ref` and `cref` were originally part of the Tuple library by
 Jaakko J\u00E4rvi. They were "promoted to `boost::` status" by

doc/scoped_enum.qbk

@@ -46,7 +46,7 @@ The user can portably declare such enumeration as follows:
     }
     BOOST_SCOPED_ENUM_DECLARE_END(future_errc)
 
-These macros allows to use `future_errc` in almost all the cases as an scoped enum.
+These macros allow using `future_errc` in almost all the cases as a scoped enum.
 
     future_errc ev = future_errc::no_state;
 
@@ -179,7 +179,7 @@ such cases.
 
 [endsect]
 
-[section Acknowledgments]
+[section Acknowledgements]
 
 This scoped enum emulation was developed by Beman Dawes, Vicente J. Botet Escriba and Anthony Williams.
 

doc/use_default.qbk

@@ -11,7 +11,7 @@ Distributed under the Boost Software License, Version 1.0.
 [section Overview]
 
 The header <boost/core/use_default.hpp> provides the type `boost::use_default`
-which is used by other Boost libraries as a sentinel type in a templates to
+which is used by other Boost libraries as a sentinel type in templates to
 indicate defaults.
 
 [endsect]

include/boost/core/bit.hpp

@@ -92,6 +92,8 @@ BOOST_CONSTEXPR inline int countl_impl( boost::ulong_long_type x ) BOOST_NOEXCEP
 template<class T>
 BOOST_CONSTEXPR int countl_zero( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return boost::core::detail::countl_impl( x );
 }
 
@@ -169,6 +171,8 @@ inline int countl_impl( boost::uint16_t x ) BOOST_NOEXCEPT
 template<class T>
 int countl_zero( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     BOOST_STATIC_ASSERT( sizeof(T) == sizeof(boost::uint8_t) || sizeof(T) == sizeof(boost::uint16_t) || sizeof(T) == sizeof(boost::uint32_t) || sizeof(T) == sizeof(boost::uint64_t) );
 
     BOOST_IF_CONSTEXPR ( sizeof(T) == sizeof(boost::uint8_t) )
@@ -194,6 +198,8 @@ int countl_zero( T x ) BOOST_NOEXCEPT
 template<class T>
 BOOST_CONSTEXPR int countl_one( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return boost::core::countl_zero( static_cast<T>( ~x ) );
 }
 
@@ -234,6 +240,8 @@ BOOST_CONSTEXPR inline int countr_impl( boost::ulong_long_type x ) BOOST_NOEXCEP
 template<class T>
 BOOST_CONSTEXPR int countr_zero( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return boost::core::detail::countr_impl( x );
 }
 
@@ -304,6 +312,8 @@ inline int countr_impl( boost::uint16_t x ) BOOST_NOEXCEPT
 template<class T>
 int countr_zero( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     BOOST_STATIC_ASSERT( sizeof(T) == sizeof(boost::uint8_t) || sizeof(T) == sizeof(boost::uint16_t) || sizeof(T) == sizeof(boost::uint32_t) || sizeof(T) == sizeof(boost::uint64_t) );
 
     BOOST_IF_CONSTEXPR ( sizeof(T) == sizeof(boost::uint8_t) )
@@ -329,6 +339,8 @@ int countr_zero( T x ) BOOST_NOEXCEPT
 template<class T>
 BOOST_CONSTEXPR int countr_one( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return boost::core::countr_zero( static_cast<T>( ~x ) );
 }
 
@@ -377,6 +389,8 @@ BOOST_CORE_POPCOUNT_CONSTEXPR inline int popcount_impl( boost::ulong_long_type x
 template<class T>
 BOOST_CONSTEXPR int popcount( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return boost::core::detail::popcount_impl( x );
 }
 
@@ -408,6 +422,8 @@ BOOST_CXX14_CONSTEXPR inline int popcount_impl( boost::uint64_t x ) BOOST_NOEXCE
 template<class T>
 BOOST_CXX14_CONSTEXPR int popcount( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     BOOST_STATIC_ASSERT( sizeof(T) <= sizeof(boost::uint64_t) );
 
     BOOST_IF_CONSTEXPR ( sizeof(T) <= sizeof(boost::uint32_t) )
@@ -427,6 +443,8 @@ BOOST_CXX14_CONSTEXPR int popcount( T x ) BOOST_NOEXCEPT
 template<class T>
 BOOST_CXX14_CONSTEXPR T rotl( T x, int s ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     unsigned const mask = std::numeric_limits<T>::digits - 1;
     return x << (s & mask) | x >> ((-s) & mask);
 }
@@ -434,6 +452,8 @@ BOOST_CXX14_CONSTEXPR T rotl( T x, int s ) BOOST_NOEXCEPT
 template<class T>
 BOOST_CXX14_CONSTEXPR T rotr( T x, int s ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     unsigned const mask = std::numeric_limits<T>::digits - 1;
     return x >> (s & mask) | x << ((-s) & mask);
 }
@@ -443,21 +463,27 @@ BOOST_CXX14_CONSTEXPR T rotr( T x, int s ) BOOST_NOEXCEPT
 template<class T>
 BOOST_CONSTEXPR bool has_single_bit( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return x != 0 && ( x & ( x - 1 ) ) == 0;
 }
 
-// bit_width should return int, https://cplusplus.github.io/LWG/issue3656
+// bit_width returns `int` now, https://cplusplus.github.io/LWG/issue3656
+// has been applied to C++20 as a DR
 
 template<class T>
-BOOST_CONSTEXPR T bit_width( T x ) BOOST_NOEXCEPT
+BOOST_CONSTEXPR int bit_width( T x ) BOOST_NOEXCEPT
 {
-    return static_cast<T>(
-        std::numeric_limits<T>::digits - boost::core::countl_zero( x ) );
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
+    return std::numeric_limits<T>::digits - boost::core::countl_zero( x );
 }
 
 template<class T>
 BOOST_CONSTEXPR T bit_floor( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     return x == 0? 0: T(1) << ( boost::core::bit_width( x ) - 1 );
 }
 
@@ -510,6 +536,8 @@ BOOST_CXX14_CONSTEXPR inline boost::uint64_t bit_ceil_impl( boost::uint64_t x )
 template<class T>
 BOOST_CXX14_CONSTEXPR T bit_ceil( T x ) BOOST_NOEXCEPT
 {
+    BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_integer && !std::numeric_limits<T>::is_signed );
+
     BOOST_STATIC_ASSERT( sizeof(T) <= sizeof(boost::uint64_t) );
 
     BOOST_IF_CONSTEXPR ( sizeof(T) <= sizeof(boost::uint32_t) )

include/boost/core/detail/string_view.hpp

@@ -403,6 +403,22 @@ public:
     {
     }
 
+#if !defined(BOOST_NO_CXX11_NULLPTR)
+# if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS)
+
+    basic_string_view( std::nullptr_t ) = delete;
+
+# else
+
+private:
+
+    basic_string_view( std::nullptr_t );
+
+public:
+
+# endif
+#endif
+
     // BOOST_CONSTEXPR basic_string_view& operator=( basic_string_view const& ) BOOST_NOEXCEPT & = default;
 
     // conversions

include/boost/core/empty_value.hpp

@@ -56,37 +56,37 @@ public:
 #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
     empty_value() = default;
 #else
-    empty_value() { }
+    BOOST_CONSTEXPR empty_value() { }
 #endif
 
-    empty_value(boost::empty_init_t)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t)
         : value_() { }
 
 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
     template<class U, class... Args>
-    empty_value(boost::empty_init_t, U&& value, Args&&... args)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value, Args&&... args)
         : value_(std::forward<U>(value), std::forward<Args>(args)...) { }
 #else
     template<class U>
-    empty_value(boost::empty_init_t, U&& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value)
         : value_(std::forward<U>(value)) { }
 #endif
 #else
     template<class U>
-    empty_value(boost::empty_init_t, const U& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, const U& value)
         : value_(value) { }
 
     template<class U>
-    empty_value(boost::empty_init_t, U& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U& value)
         : value_(value) { }
 #endif
 
-    const T& get() const BOOST_NOEXCEPT {
+    BOOST_CONSTEXPR const T& get() const BOOST_NOEXCEPT {
         return value_;
     }
 
-    T& get() BOOST_NOEXCEPT {
+    BOOST_CXX14_CONSTEXPR T& get() BOOST_NOEXCEPT {
         return value_;
     }
 
@@ -104,37 +104,37 @@ public:
 #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
     empty_value() = default;
 #else
-    empty_value() { }
+    BOOST_CONSTEXPR empty_value() { }
 #endif
 
-    empty_value(boost::empty_init_t)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t)
         : T() { }
 
 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
     template<class U, class... Args>
-    empty_value(boost::empty_init_t, U&& value, Args&&... args)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value, Args&&... args)
         : T(std::forward<U>(value), std::forward<Args>(args)...) { }
 #else
     template<class U>
-    empty_value(boost::empty_init_t, U&& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value)
         : T(std::forward<U>(value)) { }
 #endif
 #else
     template<class U>
-    empty_value(boost::empty_init_t, const U& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, const U& value)
         : T(value) { }
 
     template<class U>
-    empty_value(boost::empty_init_t, U& value)
+    BOOST_CONSTEXPR empty_value(boost::empty_init_t, U& value)
         : T(value) { }
 #endif
 
-    const T& get() const BOOST_NOEXCEPT {
+    BOOST_CONSTEXPR const T& get() const BOOST_NOEXCEPT {
         return *this;
     }
 
-    T& get() BOOST_NOEXCEPT {
+    BOOST_CXX14_CONSTEXPR T& get() BOOST_NOEXCEPT {
         return *this;
     }
 };

include/boost/core/fclose_deleter.hpp

@@ -0,0 +1,46 @@
+/*
+ *             Copyright Andrey Semashev 2022.
+ * 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)
+ */
+/*!
+ * \file   fclose_deleter.hpp
+ * \author Andrey Semashev
+ * \date   21.09.2022
+ *
+ * This header contains an \c fclose_deleter implementation. This is a deleter
+ * function object that invokes <tt>std::fclose</tt> on the passed pointer to
+ * a <tt>std::FILE</tt> structure.
+ */
+
+#ifndef BOOST_CORE_FCLOSE_DELETER_HPP
+#define BOOST_CORE_FCLOSE_DELETER_HPP
+
+#include <cstdio>
+#include <boost/config.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+//! A function object that closes a file
+struct fclose_deleter
+{
+    //! Function object result type
+    typedef void result_type;
+    /*!
+     * Closes the file handle
+     */
+    void operator() (std::FILE* p) const BOOST_NOEXCEPT
+    {
+        if (BOOST_LIKELY(!!p))
+            std::fclose(p);
+    }
+};
+
+} // namespace boost
+
+#endif // BOOST_CORE_FCLOSE_DELETER_HPP

include/boost/core/lightweight_test.hpp

@@ -202,6 +202,13 @@ inline unsigned long test_output_impl( char32_t const& v ) { return v; }
 #pragma warning(disable: 4996)
 #endif
 
+// Use snprintf if available as some compilers (clang 14.0) issue deprecation warnings for sprintf
+#if ( defined(_MSC_VER) && _MSC_VER < 1900 ) || ( defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR) )
+# define BOOST_CORE_DETAIL_SNPRINTF(buffer, format, arg) std::sprintf(buffer, format, arg)
+#else
+# define BOOST_CORE_DETAIL_SNPRINTF(buffer, format, arg) std::snprintf(buffer, sizeof(buffer)/sizeof(buffer[0]), format, arg)
+#endif
+
 inline std::string test_output_impl( char const& v )
 {
     if( std::isprint( static_cast<unsigned char>( v ) ) )
@@ -211,12 +218,14 @@ inline std::string test_output_impl( char const& v )
     else
     {
         char buffer[ 8 ];
-        std::sprintf( buffer, "\\x%02X", static_cast<unsigned char>( v ) );
+        BOOST_CORE_DETAIL_SNPRINTF( buffer, "\\x%02X", static_cast<unsigned char>( v ) );
 
         return buffer;
     }
 }
 
+#undef BOOST_CORE_DETAIL_SNPRINTF
+
 #if defined(_MSC_VER)
 #pragma warning(pop)
 #endif

include/boost/core/type_name.hpp

@@ -185,14 +185,23 @@ template<class T> std::string array_template_name()
 # pragma warning( disable: 4996 )
 #endif
 
+// Use snprintf if available as some compilers (clang 14.0) issue deprecation warnings for sprintf
+#if ( defined(_MSC_VER) && _MSC_VER < 1900 ) || ( defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR) )
+# define BOOST_CORE_DETAIL_SNPRINTF(buffer, format, arg) std::sprintf(buffer, format, arg)
+#else
+# define BOOST_CORE_DETAIL_SNPRINTF(buffer, format, arg) std::snprintf(buffer, sizeof(buffer)/sizeof(buffer[0]), format, arg)
+#endif
+
 inline std::string tn_to_string( std::size_t n )
 {
     char buffer[ 32 ];
-    std::sprintf( buffer, "%lu", static_cast< unsigned long >( n ) );
+    BOOST_CORE_DETAIL_SNPRINTF( buffer, "%lu", static_cast< unsigned long >( n ) );
 
     return buffer;
 }
 
+#undef BOOST_CORE_DETAIL_SNPRINTF
+
 #if defined(BOOST_MSVC)
 # pragma warning( pop )
 #endif

test/CMakeLists.txt

@@ -27,6 +27,10 @@ set(BOOST_TEST_LINK_LIBRARIES Boost::core Boost::utility)
 
 boost_test(TYPE run SOURCES sv_conversion_test2.cpp)
 
+set(BOOST_TEST_LINK_LIBRARIES Boost::core Boost::config Boost::move Boost::smart_ptr)
+
+boost_test(TYPE run SOURCES fclose_deleter_test.cpp)
+
 endif()
 
 add_subdirectory(swap)

test/Jamfile.v2

@@ -14,6 +14,8 @@ project : requirements
   <warnings>extra
   <toolset>msvc:<warnings-as-errors>on
   <toolset>clang:<warnings-as-errors>on
+  # https://github.com/boostorg/type_traits/issues/173
+  <toolset>clang-15:<cxxflags>-Wno-deprecated-builtins
   <toolset>gcc:<warnings-as-errors>on
   <toolset>gcc-4.4:<cxxflags>-Wno-sign-compare ;
 
@@ -174,7 +176,7 @@ run demangle_test.cpp
 run demangled_name_test.cpp
   : : : <test-info>always_show_run_output ;
 
-run demangled_name_test.cpp  : : : <rtti>off <test-info>always_show_run_output : demangled_name_test_no_rtti ;
+run demangled_name_test.cpp : : : <rtti>off <test-info>always_show_run_output : demangled_name_test_no_rtti ;
 
 run scoped_enum.cpp ;
 compile-fail scoped_enum_compile_fail_conv_from_int.cpp
@@ -184,6 +186,8 @@ compile-fail scoped_enum_compile_fail_conv_to_int.cpp
 
 run underlying_type.cpp ;
 
+run fclose_deleter_test.cpp : : : <target-os>windows:<define>_CRT_SECURE_NO_WARNINGS <target-os>windows:<define>_CRT_SECURE_NO_DEPRECATE ;
+
 run pointer_traits_pointer_test.cpp ;
 run pointer_traits_element_type_test.cpp ;
 run pointer_traits_difference_type_test.cpp ;
@@ -203,6 +207,7 @@ compile first_scalar_constexpr_test.cpp ;
 run empty_value_test.cpp ;
 run empty_value_size_test.cpp ;
 run empty_value_final_test.cpp ;
+run empty_value_constexpr_test.cpp ;
 
 run quick_exit_test.cpp ;
 run-fail quick_exit_fail.cpp ;
@@ -293,6 +298,9 @@ run bit_popcount_test.cpp
 run bit_endian_test.cpp
   : : : $(pedantic-errors) ;
 
+compile-fail bit_width_fail.cpp
+  : <warnings>off ;
+
 run type_name_test.cpp ;
 
 run sv_types_test.cpp ;
@@ -324,6 +332,8 @@ run sv_conversion_test2.cpp : ;
 run sv_common_reference_test.cpp ;
 compile sv_common_reference_test2.cpp ;
 compile sv_windows_h_test.cpp ;
+compile-fail sv_nullptr_fail.cpp
+  : $(warning-as-errors-off) ;
 
 run span_test.cpp ;
 run span_types_test.cpp ;

test/bit_width_fail.cpp

@@ -0,0 +1,13 @@
+// Negative test for boost/core/bit.hpp (bit_width)
+//
+// Copyright 2022 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/bit.hpp>
+
+int main()
+{
+    // should fail, because 0 is a signed integral type
+    return boost::core::bit_width( 0 );
+}

test/empty_value_constexpr_test.cpp

@@ -0,0 +1,65 @@
+/*
+Copyright 2022 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_CONSTEXPR)
+#include <boost/core/empty_value.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct empty {
+    constexpr int value() const {
+        return 1;
+    }
+};
+
+class type {
+public:
+    explicit constexpr type(int count)
+        : value_(count) { }
+
+    constexpr int value() const {
+        return value_;
+    }
+
+private:
+    int value_;
+};
+
+void test_int()
+{
+    constexpr boost::empty_value<int> v(boost::empty_init_t(), 4);
+    constexpr int c = v.get();
+    BOOST_TEST_EQ(c, 4);
+}
+
+void test_empty()
+{
+    constexpr boost::empty_value<empty> v = boost::empty_init_t();
+    constexpr int c = v.get().value();
+    BOOST_TEST_EQ(c, 1);
+}
+
+void test_type()
+{
+    constexpr boost::empty_value<type> v(boost::empty_init_t(), 2);
+    constexpr int c = v.get().value();
+    BOOST_TEST_EQ(c, 2);
+}
+
+int main()
+{
+    test_int();
+    test_empty();
+    test_type();
+    return boost::report_errors();
+}
+#else
+int main()
+{
+    return 0;
+}
+#endif

test/fclose_deleter_test.cpp

@@ -0,0 +1,73 @@
+/*
+ *             Copyright Andrey Semashev 2022.
+ * 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)
+ */
+/*!
+ * \file   fclose_deleter_test.cpp
+ * \author Andrey Semashev
+ * \date   21.09.2022
+ *
+ * This file contains tests for \c boost::fclose_deleter.
+ */
+
+#include <boost/core/fclose_deleter.hpp>
+#include <cstdio>
+#include <cstddef>
+#include <boost/config.hpp>
+#include <boost/move/unique_ptr.hpp>
+#include <boost/smart_ptr/shared_ptr.hpp>
+#if !defined(BOOST_NO_CXX11_SMART_PTR)
+#include <memory>
+#endif
+
+boost::movelib::unique_ptr< std::FILE, boost::fclose_deleter > make_boost_unique_file(const char* filename)
+{
+    return boost::movelib::unique_ptr< std::FILE, boost::fclose_deleter >(std::fopen(filename, "w"));
+}
+
+boost::shared_ptr< std::FILE > make_boost_shared_file(const char* filename)
+{
+    return boost::shared_ptr< std::FILE >(std::fopen(filename, "w"), boost::fclose_deleter());
+}
+
+#if !defined(BOOST_NO_CXX11_SMART_PTR)
+std::unique_ptr< std::FILE, boost::fclose_deleter > make_std_unique_file(const char* filename)
+{
+    return std::unique_ptr< std::FILE, boost::fclose_deleter >(std::fopen(filename, "w"));
+}
+
+std::shared_ptr< std::FILE > make_std_shared_file(const char* filename)
+{
+    return std::shared_ptr< std::FILE >(std::fopen(filename, "w"), boost::fclose_deleter());
+}
+#endif
+
+int main()
+{
+    const char* const filename = "fcd_test.txt";
+
+    std::FILE* file = std::fopen(filename, "w");
+    if (file)
+    {
+        boost::fclose_deleter()(file);
+        file = NULL;
+    }
+
+    make_boost_unique_file(filename);
+    make_boost_shared_file(filename);
+
+#if !defined(BOOST_NO_CXX11_SMART_PTR)
+    make_std_unique_file(filename);
+    make_std_shared_file(filename);
+#endif
+
+    // Test if the deleter can be called on a NULL pointer
+    boost::shared_ptr< std::FILE >(static_cast< std::FILE* >(NULL), boost::fclose_deleter());
+#if !defined(BOOST_NO_CXX11_SMART_PTR)
+    std::shared_ptr< std::FILE >(static_cast< std::FILE* >(NULL), boost::fclose_deleter());
+#endif
+
+    std::remove(filename);
+}

test/quick.cpp

@@ -20,6 +20,7 @@
 #include <boost/core/lightweight_test.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/core/null_deleter.hpp>
+#include <boost/core/fclose_deleter.hpp>
 #include <boost/core/pointer_traits.hpp>
 #include <boost/ref.hpp>
 #include <boost/core/scoped_enum.hpp>

test/sv_nullptr_fail.cpp

@@ -0,0 +1,19 @@
+// Copyright 2022 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/detail/string_view.hpp>
+#include <boost/config.hpp>
+
+#if defined(BOOST_NO_CXX11_NULLPTR)
+
+#error BOOST_NO_CXX11_NULLPTR is defined, test will be skipped.
+
+#else
+
+int main()
+{
+    return boost::core::string_view( nullptr ).size() == 0;
+}
+
+#endif