fine-tuned element prefetching in unprotected_bulk_visit

cxx03 deprecation

.appveyor.yml

@@ -31,14 +31,9 @@ environment:
     B2_VARIANT: debug,release
 
   matrix:
-    - FLAVOR: Visual Studio 2008, 2010, 2012
+    - FLAVOR: Visual Studio 2015
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      B2_TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
-      B2_ADDRESS_MODEL: 32 # No 64bit support
-
-    - FLAVOR: Visual Studio 2013, 2015
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      B2_TOOLSET: msvc-12.0,msvc-14.0
+      B2_TOOLSET: msvc-14.0
 
     - FLAVOR: Visual Studio 2017, C++14
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
@@ -55,43 +50,27 @@ environment:
       B2_CXXSTD: latest
       B2_TOOLSET: msvc-14.1
 
-    - FLAVOR: cygwin (32-bit, C++03,11)
+    - FLAVOR: cygwin (32-bit, C++11)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       ADDPATH: C:\cygwin\bin;
       B2_ADDRESS_MODEL: 32
-      B2_CXXSTD: 03,11
+      B2_CXXSTD: 11
       B2_TOOLSET: gcc
 
-    - FLAVOR: cygwin (32-bit, C++14,1z)
+    - FLAVOR: cygwin (32-bit, C++14)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       ADDPATH: C:\cygwin\bin;
       B2_ADDRESS_MODEL: 32
-      B2_CXXSTD: 14,1z
+      B2_CXXSTD: 14
       B2_TOOLSET: gcc
 
-    - FLAVOR: cygwin (64-bit, C++03,11)
+    - FLAVOR: cygwin (32-bit, C++1z)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      ADDPATH: C:\cygwin64\bin;
-      B2_ADDRESS_MODEL: 64
-      B2_CXXSTD: 03,11
+      ADDPATH: C:\cygwin\bin;
+      B2_ADDRESS_MODEL: 32
+      B2_CXXSTD: 1z
       B2_TOOLSET: gcc
 
-    - FLAVOR: cygwin (64-bit, C++14,1z)
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      ADDPATH: C:\cygwin64\bin;
-      B2_ADDRESS_MODEL: 64
-      B2_CXXSTD: 14,1z
-      B2_TOOLSET: gcc
-
-    - FLAVOR: cygwin (64-bit, latest, C++03)
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
-      ADDPATH: C:\cygwin64\bin;
-      B2_ADDRESS_MODEL: 64
-      B2_CXXSTD: 03
-      B2_TOOLSET: gcc
-      B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
-      B2_VARIANT: release
-
     - FLAVOR: cygwin (64-bit, latest, C++11)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
       ADDPATH: C:\cygwin64\bin;
@@ -119,13 +98,6 @@ environment:
       B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
       B2_VARIANT: release
 
-    - FLAVOR: mingw-w64, 32 bit, C++03
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
-      B2_CXXSTD: 03
-      B2_TOOLSET: gcc
-      B2_ADDRESS_MODEL: 32
-
     - FLAVOR: mingw-w64, 32 bit, C++11
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
@@ -154,13 +126,6 @@ environment:
       B2_TOOLSET: gcc
       B2_ADDRESS_MODEL: 32
 
-    - FLAVOR: mingw-w64, 64 bit, C++03
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
-      B2_CXXSTD: 03
-      B2_TOOLSET: gcc
-      B2_ADDRESS_MODEL: 64
-
     - FLAVOR: mingw-w64, 64 bit, C++11
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;

.drone.jsonnet

@@ -100,40 +100,16 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
 };
 
 [
-    linux_pipeline(
-        "Linux 14.04 GCC 4.4 32/64",
-        "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-4.4', CXXSTD: '98,0x', ADDRMD: '32,64' },
-        "g++-4.4-multilib",
-        [ "ppa:ubuntu-toolchain-r/test" ],
-    ),
-
-    linux_pipeline(
-        "Linux 14.04 GCC 4.6 32/64",
-        "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-4.6', CXXSTD: '98,0x', ADDRMD: '32,64' },
-        "g++-4.6-multilib",
-        [ "ppa:ubuntu-toolchain-r/test" ],
-    ),
-
-    linux_pipeline(
-        "Linux 14.04 GCC 4.7 32/64",
-        "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-4.7', CXXSTD: '98,0x', ADDRMD: '32,64' },
-        "g++-4.7-multilib",
-        [ "ppa:ubuntu-toolchain-r/test" ],
-    ),
-
     linux_pipeline(
         "Linux 14.04 GCC 4.8* 32/64",
         "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11', ADDRMD: '32,64' },
     ),
 
     linux_pipeline(
         "Linux 14.04 GCC 4.9 32/64",
         "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '03,11', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '11', ADDRMD: '32,64' },
         "g++-4.9-multilib",
         [ "ppa:ubuntu-toolchain-r/test" ],
     ),
@@ -141,26 +117,26 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     linux_pipeline(
         "Linux 16.04 GCC 5* 32/64",
         "cppalliance/droneubuntu1604:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14', ADDRMD: '32,64' },
     ),
 
     linux_pipeline(
         "Linux 18.04 GCC 6 32/64",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-6', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++-6', CXXSTD: '11,14', ADDRMD: '32,64' },
         "g++-6-multilib",
     ),
 
     linux_pipeline(
         "Linux 18.04 GCC 7* 32/64",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17', ADDRMD: '32,64' },
     ),
 
     linux_pipeline(
-        "Linux 18.04 GCC 8 32/64 (03,11)",
+        "Linux 18.04 GCC 8 32/64 (11)",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-8', CXXSTD: '03,11', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++-8', CXXSTD: '11', ADDRMD: '32,64' },
         "g++-8-multilib",
     ),
 
@@ -172,9 +148,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 20.04 GCC 9* 32/64 (03,11,14)",
+        "Linux 20.04 GCC 9* 32/64 (11,14)",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14', ADDRMD: '32,64' },
     ),
 
     linux_pipeline(
@@ -186,14 +162,14 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     linux_pipeline(
         "Linux 20.04 GCC 9* ARM64",
         "cppalliance/droneubuntu2004:multiarch",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' },
         arch="arm64",
     ),
 
     linux_pipeline(
-        "Linux 20.04 GCC 9* S390x (03,11,14)",
+        "Linux 20.04 GCC 9* S390x (11,14)",
         "cppalliance/droneubuntu2004:multiarch",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14' },
         arch="s390x",
     ),
 
@@ -205,9 +181,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 20.04 GCC 10 32/64 (03,11,14)",
+        "Linux 20.04 GCC 10 32/64 (11,14)",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-10', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++-10', CXXSTD: '11,14', ADDRMD: '32,64' },
         "g++-10-multilib",
     ),
 
@@ -219,9 +195,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 22.04 GCC 11* 32/64 (03,11,14)",
+        "Linux 22.04 GCC 11* 32/64 (11,14)",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14', ADDRMD: '32,64' },
     ),
 
     linux_pipeline(
@@ -231,9 +207,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 22.04 GCC 12 32 ASAN (03,11,14)",
+        "Linux 22.04 GCC 12 32 ASAN (11,14)",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '03,11', ADDRMD: '32' } + asan,
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '11', ADDRMD: '32' } + asan,
         "g++-12-multilib",
     ),
 
@@ -266,9 +242,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 22.04 GCC 12 64 ASAN (03,11,14)",
+        "Linux 22.04 GCC 12 64 ASAN (11,14)",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '03,11,14', ADDRMD: '64' } + asan,
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '11,14', ADDRMD: '64' } + asan,
         "g++-12-multilib",
     ),
 
@@ -301,9 +277,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 23.04 GCC 13 32/64 (03,11,14)",
+        "Linux 23.04 GCC 13 32/64 (11,14)",
         "cppalliance/droneubuntu2304:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14', ADDRMD: '32,64' },
         "g++-13 g++-13-multilib",
     ),
 
@@ -317,112 +293,112 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     linux_pipeline(
         "Linux 16.04 Clang 3.5",
         "cppalliance/droneubuntu1604:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-3.5', CXXSTD: '03,11' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.5', CXXSTD: '11' },
         "clang-3.5",
     ),
 
     linux_pipeline(
         "Linux 16.04 Clang 3.6",
         "cppalliance/droneubuntu1604:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-3.6', CXXSTD: '03,11,14' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.6', CXXSTD: '11,14' },
         "clang-3.6",
     ),
 
     linux_pipeline(
         "Linux 16.04 Clang 3.7",
         "cppalliance/droneubuntu1604:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-3.7', CXXSTD: '03,11,14' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.7', CXXSTD: '11,14' },
         "clang-3.7",
     ),
 
     linux_pipeline(
         "Linux 16.04 Clang 3.8",
         "cppalliance/droneubuntu1604:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-3.8', CXXSTD: '03,11,14' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.8', CXXSTD: '11,14' },
         "clang-3.8",
     ),
 
     linux_pipeline(
         "Linux 18.04 Clang 3.9",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '03,11,14' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '11,14' },
         "clang-3.9",
     ),
 
     linux_pipeline(
         "Linux 18.04 Clang 4.0",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '03,11,14' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '11,14' },
         "clang-4.0",
     ),
 
     linux_pipeline(
         "Linux 18.04 Clang 5.0",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14,1z' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '11,14,1z' },
         "clang-5.0",
     ),
 
     linux_pipeline(
         "Linux 18.04 Clang 6.0",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '03,11,14,17' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '11,14,17' },
         "clang-6.0",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 7",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '03,11,14,17' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '11,14,17' },
         "clang-7",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 8",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '03,11,14,17' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '11,14,17' },
         "clang-8",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 9",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '03,11,14,17,2a' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '11,14,17,2a' },
         "clang-9",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 10",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '03,11,14,17,2a' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '11,14,17,2a' },
         "clang-10",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 11",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '03,11,14,17,2a' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '11,14,17,2a' },
         "clang-11",
     ),
 
     linux_pipeline(
         "Linux 20.04 Clang 12",
         "cppalliance/droneubuntu2004:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '03,11,14,17,2a' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '11,14,17,2a' },
         "clang-12",
     ),
 
     linux_pipeline(
         "Linux 22.04 Clang 13",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-13', CXXSTD: '03,11,14,17,20' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-13', CXXSTD: '11,14,17,20' },
         "clang-13",
     ),
 
     linux_pipeline(
-        "Linux 22.04 Clang 14 UBSAN (03,11,14)",
+        "Linux 22.04 Clang 14 UBSAN (11,14)",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '03,11,14' } + ubsan,
+        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '11,14' } + ubsan,
         "clang-14",
     ),
 
@@ -434,9 +410,9 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 22.04 Clang 14 ASAN (03,11,14)",
+        "Linux 22.04 Clang 14 ASAN (11,14)",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '03,11,14' } + asan,
+        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '11,14' } + asan,
         "clang-14",
     ),
 
@@ -457,14 +433,14 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     linux_pipeline(
         "Linux 22.04 Clang 15",
         "cppalliance/droneubuntu2204:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-15', CXXSTD: '03,11,14,17,20,2b' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-15', CXXSTD: '11,14,17,20,2b' },
         "clang-15",
         ["deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-15 main"],
     ),
 
     macos_pipeline(
-        "MacOS 10.15 Xcode 12.2 UBSAN (03,11)",
-        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11' } + ubsan,
+        "MacOS 10.15 Xcode 12.2 UBSAN (11)",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11' } + ubsan,
     ),
 
     macos_pipeline(
@@ -479,7 +455,7 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
 
     macos_pipeline(
         "MacOS 12.4 Xcode 13.4.1 ASAN",
-        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + asan,
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,1z' } + asan,
         xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
     ),
 

.drone/drone.bat

@@ -20,4 +20,4 @@ b2 -d0 headers
 
 if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
 if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+b2 --abbreviate-paths -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker

.github/workflows/ci.yml

@@ -32,6 +32,16 @@ env:
   CODECOV_NAME: Github Actions
 
 jobs:
+  runner-selection:
+    # runs-on: ubuntu-latest
+    runs-on: ${{ github.repository_owner == 'boostorg' && fromJSON('[ "self-hosted", "linux", "x64", "ubuntu-latest-aws" ]') || 'ubuntu-latest' }}
+    outputs:
+      labelmatrix: ${{ steps.aws_hosted_runners.outputs.labelmatrix }}
+    steps:
+      - name: AWS Hosted Runners
+        id: aws_hosted_runners
+        uses: cppalliance/aws-hosted-runners@v1.0.0
+
   posix:
     defaults:
       run:
@@ -42,50 +52,71 @@ jobs:
       matrix:
         include:
           # Linux, gcc
-          - { compiler: gcc-7,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-7' }
-          - { compiler: gcc-8,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-8' }
-          - { compiler: gcc-9,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-9' }
-          - { compiler: gcc-10,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-10' }
-          - { compiler: gcc-11,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-11' }
-          - { name: "gcc-12 w/ sanitizers (03,11,14)", sanitize: yes,
-              compiler: gcc-12,    cxxstd: '03,11,14',       os: ubuntu-22.04, ccache_key: "san1" }
-          - { name: "gcc-12 w/ sanitizers (17,20,2b)", sanitize: yes,
-              compiler: gcc-12,    cxxstd: '17,20,2b',       os: ubuntu-22.04, ccache_key: "san2" }
+          - { compiler: gcc-7,     cxxstd: '11,14,17',    os: 'ubuntu-20.04', install: 'g++-7' }
+          - { compiler: gcc-8,     cxxstd: '11,14,17',    os: 'ubuntu-20.04', install: 'g++-8' }
+          - { compiler: gcc-9,     cxxstd: '11,14,17',    os: 'ubuntu-22.04', install: 'g++-9' }
+          - { compiler: gcc-10,    cxxstd: '11,14,17,20', os: 'ubuntu-22.04', install: 'g++-10' }
+          - { compiler: gcc-11,    cxxstd: '11,14,17,20', os: 'ubuntu-22.04', install: 'g++-11' }
+          - { name: "gcc-12 w/ sanitizers (11)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '11',          os: 'ubuntu-22.04', ccache_key: "san1" }
+          - { name: "gcc-12 w/ sanitizers (14)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '14',          os: 'ubuntu-22.04', ccache_key: "san1" }
+          - { name: "gcc-12 w/ sanitizers (17)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '17',          os: 'ubuntu-22.04', ccache_key: "san2" }
+          - { name: "gcc-12 w/ sanitizers (20)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '20',          os: 'ubuntu-22.04', ccache_key: "san2" }
+          - { name: "gcc-12 w/ sanitizers (2b)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '2b',          os: 'ubuntu-22.04', ccache_key: "san2" }
           - { name: Collect coverage, coverage: yes,
-              compiler: gcc-12,     cxxstd: '03,20',          os: ubuntu-22.04, install: 'g++-12-multilib', address-model: '32,64', ccache_key: "cov" }
+              compiler: gcc-12,    cxxstd: '20',          os: 'ubuntu-22.04', install: 'g++-12-multilib', address-model: '32,64', ccache_key: "cov" }
 
-          - { name: "cfoa tsan (gcc)", cxxstd: '11,14,17,20,2b', os: ubuntu-22.04, compiler: gcc-12,
-              targets: 'libs/unordered/test//cfoa_tests', thread-sanitize: yes }
+          - { name: "cfoa tsan (gcc-12)", cxxstd: '11,14,17,20,2b', os: 'ubuntu-22.04', compiler: gcc-12,
+              targets: 'libs/unordered/test//cfoa_tests', thread-sanitize: yes, ccache_key: "tsan" }
 
           # Linux, clang, libc++
-          - { compiler: clang-7,   cxxstd: '03,11,14,17',       os: ubuntu-20.04, stdlib: libc++, install: 'clang-7 libc++-7-dev libc++abi-7-dev' }
-          - { compiler: clang-10,  cxxstd: '03,11,14,17,20',    os: ubuntu-20.04, stdlib: libc++, install: 'clang-10 libc++-10-dev libc++abi-10-dev' }
-          - { compiler: clang-11,  cxxstd: '03,11,14,17,20',    os: ubuntu-22.04, stdlib: libc++, install: 'clang-11 libc++-11-dev libc++abi-11-dev' }
-          # clang-12 doesn't work on ubuntu-22.04, the linker can't find -lunwind for some reason
-          - { name: "clang-12 w/ sanitizers (03,11,14)", sanitize: yes,
-              compiler: clang-12,  cxxstd: '03,11,14',          os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san1" }
-          - { name: "clang-12 w/ sanitizers (17,20,2b)", sanitize: yes,
-              compiler: clang-12,  cxxstd: '17,20,2b',          os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san2" }
-          - { compiler: clang-13,  cxxstd: '03,11,14,17,20,2b', os: ubuntu-22.04, stdlib: libc++, install: 'clang-13 libc++-13-dev libc++abi-13-dev' }
-          - { compiler: clang-14,  cxxstd: '03,11,14,17,20,2b', os: ubuntu-22.04, stdlib: libc++, install: 'clang-14 libc++-14-dev libc++abi-14-dev' }
+          - { compiler: clang-7,    cxxstd: '11,14,17',    os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-7 libc++-7-dev libc++abi-7-dev' }
+          - { compiler: clang-10,   cxxstd: '11,14,17,20', os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-10 libc++-10-dev libc++abi-10-dev' }
+          - { compiler: clang-11,   cxxstd: '11,14,17,20', os: 'ubuntu-22.04', stdlib: libc++, install: 'clang-11 libc++-11-dev libc++abi-11-dev' }
+          # clang-12 doesn't work on 'ubuntu-22.04', the linker can't find -lunwind for some reason
+          - { name: "clang-12 w/ sanitizers (11,14)", sanitize: yes,
+              compiler: clang-12,   cxxstd: '11,14',       os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san1" }
+          - { name: "clang-12 w/ sanitizers (17)", sanitize: yes,
+              compiler: clang-12,   cxxstd: '17',          os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san2" }
+          - { name: "clang-12 w/ sanitizers (20)", sanitize: yes,
+              compiler: clang-12,   cxxstd: '20',          os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san2" }
+          - { name: "clang-12 w/ sanitizers (2b)", sanitize: yes,
+              compiler: clang-12,   cxxstd: '2b',          os: 'ubuntu-20.04', stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san2" }
+          - { compiler: 'clang-13', cxxstd: '11,14',       os: 'ubuntu-22.04', stdlib: libc++, install: 'clang-13 libc++-13-dev libc++abi-13-dev' }
+          - { compiler: 'clang-13', cxxstd: '17,20,2b',    os: 'ubuntu-22.04', stdlib: libc++, install: 'clang-13 libc++-13-dev libc++abi-13-dev' }
 
           # not using libc++ because of https://github.com/llvm/llvm-project/issues/52771
-          - { name: "clang-14 w/ sanitizers (03,11,14)", sanitize: yes,
-              compiler: clang-14,  cxxstd: '03,11,14',          os: ubuntu-22.04, ccache_key: "san1" }
-          - { name: "clang-14 w/ sanitizers (17,20,2b)", sanitize: yes,
-              compiler: clang-14,  cxxstd: '17,20,2b',          os: ubuntu-22.04, ccache_key: "san2" }
+          - { name: "clang-14 w/ sanitizers (11,14)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '11,14', os: 'ubuntu-22.04', ccache_key: "san1" }
+          - { name: "clang-14 w/ sanitizers (17)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '17',    os: 'ubuntu-22.04', ccache_key: "san2" }
+          - { name: "clang-14 w/ sanitizers (20)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '20',    os: 'ubuntu-22.04', ccache_key: "san2" }
+          - { name: "clang-14 w/ sanitizers (2b)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '2b',    os: 'ubuntu-22.04', ccache_key: "san2" }
 
-          - { name: "cfoa tsan (clang)", cxxstd: '11,14,17,20,2b', os: ubuntu-22.04, compiler: clang-14,
+          - { name: "cfoa tsan (clang-14)", cxxstd: '11,14,17,20,2b', os: 'ubuntu-22.04', compiler: clang-14,
               targets: 'libs/unordered/test//cfoa_tests', thread-sanitize: yes, 
-              stdlib: libc++, install: 'clang-14 libc++-14-dev libc++abi-14-dev' }
+              stdlib: libc++, install: 'clang-14 libc++-14-dev libc++abi-14-dev', ccache_key: "tsan" }
+
+          - { compiler: 'clang-15', cxxstd: '11,14',    os: 'ubuntu-22.04', stdlib: libc++, install: 'clang-15 libc++-15-dev libc++abi-15-dev' }
+          - { compiler: 'clang-15', cxxstd: '17,20,2b', os: 'ubuntu-22.04', stdlib: libc++, install: 'clang-15 libc++-15-dev libc++abi-15-dev' }
 
           # OSX, clang
-          - { compiler: clang,     cxxstd: '03,11,14,17,2a',    os: macos-11, }
-          - { compiler: clang,     cxxstd: '03,11,14,17,2a',    os: macos-12, sanitize: yes }
-          - { compiler: clang,     cxxstd: '11,14,17,2a',       os: macos-12, thread-sanitize: yes, targets: 'libs/unordered/test//cfoa_tests' }
+          - { compiler: clang, cxxstd: '11,14,17,2a',    os: 'macos-11' }
+          - { compiler: clang, cxxstd: '11,14,17,2a',    os: 'macos-12', sanitize: yes, ccache_key: "san1" }
+          - { compiler: clang, cxxstd: '11,14,17,2a',    os: 'macos-12', thread-sanitize: yes, targets: 'libs/unordered/test//cfoa_tests', ccache_key: "tsan" }
+          - { compiler: clang, cxxstd: '11,14,17,20,2b', os: 'macos-13' }
 
-    timeout-minutes: 180
-    runs-on: ${{matrix.os}}
+    timeout-minutes: 360
+    # posix (gcc-12 w/ sanitizers is taking longer than 210 minutes
+    # timeout-minutes: 210
+    needs: [runner-selection]
+    runs-on: ${{ fromJSON(needs.runner-selection.outputs.labelmatrix)[matrix.os] }}
     container: ${{matrix.container}}
     env: {B2_USE_CCACHE: 1}
 
@@ -229,15 +260,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { toolset: msvc-14.0, cxxstd: '14,latest',       addrmd: '32,64', os: windows-2019, variant: 'debug,release' }
-          - { toolset: msvc-14.2, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2019, variant: 'debug,release' }
-          - { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2022, variant: 'debug,release' }
-          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '64',    os: windows-2022, variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '/RTCc'              }
-          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '32',    os: windows-2022, variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '"/RTCc /arch:IA32"' }
-          - { toolset: clang-win, cxxstd: '14,17,latest',    addrmd: '32,64', os: windows-2022, variant: 'debug,release' }
-          - { toolset: gcc,       cxxstd: '03,11,14,17,2a',  addrmd: '64',    os: windows-2019, variant: 'debug,release' }
+          - { toolset: msvc-14.0, cxxstd: '14,latest',       addrmd: '32,64', os: 'windows-2019', variant: 'debug,release' }
+          - { toolset: msvc-14.2, cxxstd: '14,17,20,latest', addrmd: '32,64', os: 'windows-2019', variant: 'debug,release' }
+          - { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: 'windows-2022', variant: 'debug,release' }
+          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '64',    os: 'windows-2022', variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '/RTCc'              }
+          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '32',    os: 'windows-2022', variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '"/RTCc /arch:IA32"' }
+          - { toolset: clang-win, cxxstd: '14,17,latest',    addrmd: '32,64', os: 'windows-2022', variant: 'debug,release' }
+          - { toolset: gcc,       cxxstd: '11,14,17,2a',     addrmd: '64',    os: 'windows-2019', variant: 'debug,release' }
 
-    runs-on: ${{matrix.os}}
+    needs: [runner-selection]
+    runs-on: ${{ fromJSON(needs.runner-selection.outputs.labelmatrix)[matrix.os] }}
 
     steps:
       - uses: actions/checkout@v3
@@ -291,10 +323,11 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { sys: MINGW32, compiler: gcc, cxxstd: '03,11,17,20' }
-          - { sys: MINGW64, compiler: gcc, cxxstd: '03,11,17,20' }
+          - { sys: MINGW32, compiler: gcc, cxxstd: '11,17,20' }
+          - { sys: MINGW64, compiler: gcc, cxxstd: '11,17,20' }
 
-    runs-on: windows-latest
+    needs: [runner-selection]
+    runs-on: ${{ fromJSON(needs.runner-selection.outputs.labelmatrix)['windows-latest'] }}
 
     steps:
       - uses: actions/checkout@v3
@@ -348,11 +381,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { os: ubuntu-20.04, build_shared: ON,  build_type: Debug, generator: 'Unix Makefiles' }
-          - { os: windows-2019, build_shared: ON,  build_type: Debug, generator: 'Visual Studio 16 2019' }
+          - { os: 'ubuntu-20.04', build_shared: ON,  build_type: Debug, generator: 'Unix Makefiles' }
+          - { os: 'windows-2019', build_shared: ON,  build_type: Debug, generator: 'Visual Studio 16 2019' }
 
     timeout-minutes: 120
-    runs-on: ${{matrix.os}}
+    needs: [runner-selection]
+    runs-on: ${{ fromJSON(needs.runner-selection.outputs.labelmatrix)[matrix.os] }}
 
     steps:
       - uses: actions/checkout@v3

doc/unordered/benchmarks.adoc

@@ -298,7 +298,7 @@ The successful lookup benchmarks are done by looking up all `n` values, in their
 The unsuccessful lookup benchmarks use `n` randomly generated integers but using a different seed value.
 
 
-=== GCC 11, x64
+=== GCC 12, x64
 
 
 [caption=]
@@ -317,7 +317,7 @@ h|unsuccessful lookup
 
 |===
 
-=== Clang 12, x64
+=== Clang 15, x64
 
 
 [caption=]
@@ -336,7 +336,7 @@ h|unsuccessful lookup
 
 |===
 
-=== Visual Studio 2019, x64
+=== Visual Studio 2022, x64
 
 
 [caption=]
@@ -374,7 +374,7 @@ h|unsuccessful lookup
 
 |===
 
-=== GCC 11, x86
+=== GCC 12, x86
 
 
 [caption=]
@@ -393,7 +393,7 @@ h|unsuccessful lookup
 
 |===
 
-=== Clang 12, x86
+=== Clang 15, x86
 
 
 [caption=]
@@ -412,7 +412,7 @@ h|unsuccessful lookup
 
 |===
 
-=== Visual Studio 2019, x86
+=== Visual Studio 2022, x86
 
 
 [caption=]
@@ -447,6 +447,10 @@ operations follow a https://en.wikipedia.org/wiki/Zipf%27s_law#Formal_definition
 with different _skew_ parameters: the higher the skew, the more concentrated are the keys in the lower values
 of the covered range.
 
+`boost::concurrent_flat_map` is exercised using both regular and xref:#concurrent_bulk_visitation[bulk visitation]:
+in the latter case, lookup keys are buffered in a local array and then processed at
+once each time the buffer reaches xref:#concurrent_flat_map_constants[`bulk_visit_size`].
+
 === GCC 12, x64
 
 

doc/unordered/changes.adoc

@@ -6,6 +6,22 @@
 :github-pr-url: https://github.com/boostorg/unordered/pull
 :cpp: C++
 
+== Release 1.84.0 - Major update
+
+* Added `boost::concurrent_flat_set`.
+* Added `[c]visit_while` operations to concurrent containers,
+with serial and parallel variants.
+* Added efficient move construction of `boost::unordered_flat_(map|set)` from
+`boost::concurrent_flat_(map|set)` and vice versa.
+* Added bulk visitation to concurrent containers for increased lookup performance.
+* Added debug-mode mechanisms for detecting illegal reentrancies into
+a concurrent container from user code.
+* Added Boost.Serialization support to all containers and their (non-local) iterator types.
+* Added support for fancy pointers to open-addressing and concurrent containers.
+  This enables scenarios like the use of Boost.Interprocess allocators to construct containers in shared memory.
+* Starting with this release, `boost::unordered_[multi]set` and `boost::unordered_[multi]map`
+  only work with C++11 onwards.
+
 == Release 1.83.0 - Major update
 
 * Added `boost::concurrent_flat_map`, a fast, thread-safe hashmap based on open addressing.

doc/unordered/compliance.adoc

@@ -7,116 +7,54 @@
 
 == Closed-addressing Containers
 
-`unordered_[multi]set` and `unordered_[multi]map` are intended to provide a conformant
-implementation of the {cpp}20 standard that will work with {cpp}98 upwards.
-This wide compatibility does mean some compromises have to be made.
-With a compiler and library that fully support {cpp}11, the differences should
-be minor.
+`boost::unordered_[multi]set` and `boost::unordered_[multi]map` provide a conformant
+implementation for {cpp}11 (or later) compilers of the latest standard revision of
+{cpp} unordered associative containers, with very minor deviations as noted.
+The containers are fully https://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer[AllocatorAware^]
+and support https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers^].
 
-=== Move Emulation
+=== Deduction Guides
 
-Support for move semantics is implemented using Boost.Move. If rvalue
-references are available it will use them, but if not it uses a close,
-but imperfect emulation. On such compilers:
+Deduction guides for
+https://en.cppreference.com/w/cpp/language/class_template_argument_deduction[class template argument deduction (CTAD)^]
+are only available on {cpp}17 (or later) compilers.
 
-* Non-copyable objects can be stored in the containers.
-  They can be constructed in place using `emplace`, or if they support
-  Boost.Move, moved into place.
-* The containers themselves are not movable.
-* Argument forwarding is not perfect.
+=== Piecewise Pair Emplacement
 
-=== Use of Allocators
-
-{cpp}11 introduced a new allocator system. It's backwards compatible due to
-the lax requirements for allocators in the old standard, but might need
-some changes for allocators which worked with the old versions of the
-unordered containers.
-It uses a traits class, `allocator_traits` to handle the allocator
-adding extra functionality, and making some methods and types optional.
-During development a stable release of
-`allocator_traits` wasn't available so an internal partial implementation
-is always used in this version. Hopefully a future version will use the
-standard implementation where available.
-
-The member functions `construct`, `destroy` and `max_size` are now
-optional, if they're not available a fallback is used.
-A full implementation of `allocator_traits` requires sophisticated
-member function detection so that the fallback is used whenever the
-member function call is not well formed.
-This requires support for SFINAE expressions, which are available on
-GCC from version 4.4 and Clang.
-
-On other compilers, there's just a test to see if the allocator has
-a member, but no check that it can be called. So rather than using a
-fallback there will just be a compile error.
-
-`propagate_on_container_copy_assignment`,
-`propagate_on_container_move_assignment`,
-`propagate_on_container_swap` and
-`select_on_container_copy_construction` are also supported.
-Due to imperfect move emulation, some assignments might check
-`propagate_on_container_copy_assignment` on some compilers and
-`propagate_on_container_move_assignment` on others.
-
-=== Construction/Destruction Using Allocators
-
-The following support is required for full use of {cpp}11 style
-construction/destruction:
-
-* Variadic templates.
-* Piecewise construction of `std::pair`.
-* Either `std::allocator_traits` or expression SFINAE.
-
-This is detected using Boost.Config. The macro
-`BOOST_UNORDERED_CXX11_CONSTRUCTION` will be set to 1 if it is found, or 0
-otherwise.
-
-When this is the case `allocator_traits::construct` and
-`allocator_traits::destroy` will always be used, apart from when piecewise
-constructing a `std::pair` using `boost::tuple` (see <<compliance_pairs,below>>), but that should be easily avoided.
-
-When support is not available `allocator_traits::construct` and
-`allocator_traits::destroy` are never called.
-
-=== Pointer Traits
-
-`pointer_traits` aren't used. Instead, pointer types are obtained from
-rebound allocators, this can cause problems if the allocator can't be
-used with incomplete types. If `const_pointer` is not defined in the
-allocator, `boost::pointer_to_other<pointer, const value_type>::type`
-is used to obtain a const pointer.
-
-=== Pairs
-
-Since the containers use `std::pair` they're limited to the version
-from the current standard library. But since {cpp}11 ``std::pair``'s
-`piecewise_construct` based constructor is very useful, `emplace`
-emulates it with a `piecewise_construct` in the `boost::unordered`
-namespace. So for example, the following will work:
+In accordance with the standard specification,
+`boost::unordered_[multi]map::emplace` supports piecewise pair construction: 
 
 [source,c++]
 ----
 boost::unordered_multimap<std::string, std::complex> x;
 
+x.emplace(
+    std::piecewise_construct,
+    std::make_tuple("key"), std::make_tuple(1, 2));
+----
+
+Additionally, the same
+functionality is provided via non-standard `boost::unordered::piecewise_construct`
+and Boost.Tuple:
+
+[source,c++]
+----
 x.emplace(
     boost::unordered::piecewise_construct,
     boost::make_tuple("key"), boost::make_tuple(1, 2));
 ----
 
-Older drafts of the standard also supported variadic constructors
-for `std::pair`, where the first argument would be used for the
-first part of the pair, and the remaining for the second part.
+This feature has been retained for backwards compatibility with
+previous versions of Boost.Unordered: users are encouraged to
+update their code to use `std::piecewise_construct` and
+``std::tuple``s instead.
 
-=== Miscellaneous
+=== Swap
 
 When swapping, `Pred` and `Hash` are not currently swapped by calling
-`swap`, their copy constructors are used. As a consequence when swapping
+`swap`, their copy constructors are used. As a consequence, when swapping
 an exception may be thrown from their copy constructor.
 
-Variadic constructor arguments for `emplace` are only used when both
-rvalue references and variadic template parameters are available.
-Otherwise `emplace` can only take up to 10 constructors arguments.
-
 == Open-addressing Containers
 
 The C++ standard does not currently provide any open-addressing container
@@ -129,7 +67,9 @@ radically different from that imposed by the standard (closed addressing).
 Open-addressing containers provided by Boost.Unordered only work with reasonably
 compliant C++11 (or later) compilers. Language-level features such as move semantics
 and variadic template parameters are then not emulated. 
-The containers are fully https://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer[AllocatorAware^].
+The containers are fully https://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer[AllocatorAware^]
+and support https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers^].
+
 
 The main differences with C++ unordered associative containers are:
 
@@ -148,22 +88,24 @@ The main differences with C++ unordered associative containers are:
 
 == Concurrent Containers
 
-There is currently no specification in the C++ standard for this or any other concurrent
-data structure. `boost::concurrent_flat_map` takes the same template parameters as `std::unordered_map`
-and all the maps provided by Boost.Unordered, and its API is modelled after that of
-`boost::unordered_flat_map` with the crucial difference that iterators are not provided
+There is currently no specification in the C++ standard for this or any other type of concurrent
+data structure. The APIs of `boost::concurrent_flat_set` and `boost::concurrent_flat_map`
+are modelled after `std::unordered_flat_set` and `std::unordered_flat_map`, respectively,
+with the crucial difference that iterators are not provided
 due to their inherent problems in concurrent scenarios (high contention, prone to deadlocking):
-so, `boost::concurrent_flat_map` is technically not a
+so, Boost.Unordered concurrent containers are technically not models of
 https://en.cppreference.com/w/cpp/named_req/Container[Container^], although
-it meets all the requirements of https://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer[AllocatorAware^]
-containers except those implying iterators.
+they meet all the requirements of https://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer[AllocatorAware^]
+containers (including
+https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointer^] support)
+except those implying iterators.
 
 In a non-concurrent unordered container, iterators serve two main purposes:
 
 * Access to an element previously located via lookup. 
 * Container traversal.
 
-In place of iterators, `boost::concurrent_flat_map` uses _internal visitation_
+In place of iterators, `boost::concurrent_flat_set` and `boost::concurrent_flat_map` use _internal visitation_
 facilities as a thread-safe substitute. Classical operations returning an iterator to an
 element already existing in the container, like for instance:
 
@@ -191,15 +133,15 @@ template<class F> size_t visit_all(F f);
 ----
 
 of which there are parallelized versions in C++17 compilers with parallel
-algorithm support. In general, the interface of `boost::concurrent_flat_map`
-is derived from that of `boost::unordered_flat_map` by a fairly straightforward
-process of replacing iterators with visitation where applicable. If
-`iterator` and `const_iterator` provide mutable and const access to elements,
+algorithm support. In general, the interface of concurrent containers
+is derived from that of their non-concurrent counterparts by a fairly straightforward
+process of replacing iterators with visitation where applicable. If for 
+regular maps `iterator` and `const_iterator` provide mutable and const access to elements,
 respectively, here visitation is granted mutable or const access depending on
 the constness of the member function used (there are also `*cvisit` overloads for
-explicit const visitation).
+explicit const visitation); In the case of `boost::concurrent_flat_set`, visitation is always const.
 
-The one notable operation not provided is `operator[]`/`at`, which can be
+One notable operation not provided by `boost::concurrent_flat_map` is `operator[]`/`at`, which can be
 replaced, if in a more convoluted manner, by
 xref:#concurrent_flat_map_try_emplace_or_cvisit[`try_emplace_or_visit`].
 

doc/unordered/concurrent.adoc

@@ -3,8 +3,8 @@
 
 :idprefix: concurrent_
 
-Boost.Unordered currently provides just one concurrent container named `boost::concurrent_flat_map`.
-`boost::concurrent_flat_map` is a hash table that allows concurrent write/read access from
+Boost.Unordered provides `boost::concurrent_flat_set` and `boost::concurrent_flat_map`,
+hash tables that allow concurrent write/read access from
 different threads without having to implement any synchronzation mechanism on the user's side.
 
 [source,c++]
@@ -36,16 +36,16 @@ In the example above, threads access `m` without synchronization, just as we'd d
 single-threaded scenario. In an ideal setting, if a given workload is distributed among
 _N_ threads, execution is _N_ times faster than with one thread —this limit is
 never attained in practice due to synchronization overheads and _contention_ (one thread
-waiting for another to leave a locked portion of the map), but `boost::concurrent_flat_map`
-is designed to perform with very little overhead and typically achieves _linear scaling_
+waiting for another to leave a locked portion of the map), but Boost.Unordered concurrent containers
+are designed to perform with very little overhead and typically achieve _linear scaling_
 (that is, performance is proportional to the number of threads up to the number of
 logical cores in the CPU).
 
 == Visitation-based API
 
-The first thing a new user of `boost::concurrent_flat_map` will notice is that this
-class _does not provide iterators_ (which makes it technically
-not a https://en.cppreference.com/w/cpp/named_req/Container[Container^]
+The first thing a new user of `boost::concurrent_flat_set` or `boost::concurrent_flat_map`
+will notice is that these classes _do not provide iterators_ (which makes them technically
+not https://en.cppreference.com/w/cpp/named_req/Container[Containers^]
 in the C++ standard sense). The reason for this is that iterators are inherently
 thread-unsafe. Consider this hypothetical code:
 
@@ -73,7 +73,7 @@ m.visit(k, [](const auto& x) { // x is the element with key k (if it exists)
 ----
 
 The visitation function passed by the user (in this case, a lambda function)
-is executed internally by `boost::concurrent_flat_map` in
+is executed internally by Boost.Unordered in
 a thread-safe manner, so it can access the element without worrying about other
 threads interfering in the process.
 
@@ -112,7 +112,7 @@ if (found) {
 }
 ----
 
-Visitation is prominent in the API provided by `boost::concurrent_flat_map`, and
+Visitation is prominent in the API provided by `boost::concurrent_flat_set` and `boost::concurrent_flat_map`, and
 many classical operations have visitation-enabled variations:
 
 [source,c++]
@@ -129,13 +129,17 @@ the element: as a general rule, operations on a `boost::concurrent_flat_map` `m`
 will grant visitation functions const/non-const access to  the element depending on whether
 `m` is const/non-const. Const access can be always be explicitly requested
 by using `cvisit` overloads (for instance, `insert_or_cvisit`) and may result
-in higher parallelization. Consult the xref:#concurrent_flat_map[reference]
-for a complete list of available operations.
+in higher parallelization. For `boost::concurrent_flat_set`, on the other hand,
+visitation is always const access.
+Consult the references of
+xref:#concurrent_flat_set[`boost::concurrent_flat_set`] and 
+xref:#concurrent_flat_map[`boost::concurrent_flat_map`]
+for the complete list of visitation-enabled operations.
 
 == Whole-Table Visitation
 
-In the absence of iterators, `boost::concurrent_flat_map` provides `visit_all`
-as an alternative way to process all the elements in the map:
+In the absence of iterators, `visit_all` is provided
+as an alternative way to process all the elements in the container:
 
 [source,c++]
 ----
@@ -154,7 +158,28 @@ m.visit_all(std::execution::par, [](auto& x) { // run in parallel
 });
 ----
 
-There is another whole-table visitation operation, `erase_if`:
+Traversal can be interrupted midway:
+
+[source,c++]
+----
+// finds the key to a given (unique) value
+
+int  key = 0;
+int  value = ...;
+bool found = !m.visit_while([&](const auto& x) {
+  if(x.second == value) {
+    key = x.first;
+    return false; // finish
+  }
+  else {
+    return true;  // keep on visiting
+  }
+});
+
+if(found) { ... }
+----
+
+There is one last whole-table visitation operation, `erase_if`:
 
 [source,c++]
 ----
@@ -163,15 +188,64 @@ m.erase_if([](auto& x) {
 });
 ----
 
-`erase_if` can also be parallelized. Note that, in order to increase efficiency,
-these operations do not block the table during execution: this implies that elements
+`visit_while` and `erase_if` can also be parallelized. Note that, in order to increase efficiency,
+whole-table visitation operations do not block the table during execution: this implies that elements
 may be inserted, modified or erased by other threads during visitation. It is
-advisable not to assume too much about the exact global state of a `boost::concurrent_flat_map`
+advisable not to assume too much about the exact global state of a concurrent container
 at any point in your program.
 
+== Bulk visitation
+
+Suppose you have an `std::array` of keys you want to look up for in a concurrent map:
+
+[source,c++]
+----
+std::array<int, N> keys;
+...
+for(const auto& key: keys) {
+  m.visit(key, [](auto& x) { ++x.second; });
+}
+----
+
+_Bulk visitation_ allows us to pass all the keys in one operation:
+
+[source,c++]
+----
+m.visit(keys.begin(), keys.end(), [](auto& x) { ++x.second; });
+----
+
+This functionality is not provided for mere syntactic convenience, though: by processing all the
+keys at once, some internal optimizations can be applied that increase
+performance over the regular, one-at-a-time case (consult the
+xref:#benchmarks_boostconcurrent_flat_map[benchmarks]). In fact, it may be beneficial
+to buffer incoming keys so that they can be bulk visited in chunks:
+
+[source,c++]
+----
+static constexpr auto bulk_visit_size = boost::concurrent_flat_map<int,int>::bulk_visit_size;
+std::array<int, bulk_visit_size> buffer;
+std::size_t                      i=0;
+while(...) { // processing loop
+  ...
+  buffer[i++] = k;
+  if(i == bulk_visit_size) {
+    map.visit(buffer.begin(), buffer.end(), [](auto& x) { ++x.second; });
+    i = 0;
+  }
+  ...
+}
+// flush remaining keys
+map.visit(buffer.begin(), buffer.begin() + i, [](auto& x) { ++x.second; });
+----
+
+There's a latency/throughput tradeoff here: it will take longer for incoming keys to
+be processed (since they are buffered), but the number of processed keys per second
+is higher. `bulk_visit_size` is the recommended chunk size —smaller buffers
+may yield worse performance.
+
 == Blocking Operations
 
-``boost::concurrent_flat_map``s can be copied, assigned, cleared and merged just like any
+``boost::concurrent_flat_set``s  and ``boost::concurrent_flat_map``s can be copied, assigned, cleared and merged just like any
 Boost.Unordered container. Unlike most other operations, these are _blocking_,
 that is, all other threads are prevented from accesing the tables involved while a copy, assignment,
 clear or merge operation is in progress. Blocking is taken care of automatically by the library
@@ -180,3 +254,31 @@ and the user need not take any special precaution, but overall performance may b
 Another blocking operation is _rehashing_, which happens explicitly via `rehash`/`reserve`
 or during insertion when the table's load hits `max_load()`. As with non-concurrent containers,
 reserving space in advance of bulk insertions will generally speed up the process.
+
+== Interoperability with non-concurrent containers
+
+As open-addressing and concurrent containers are based on the same internal data structure,
+`boost::unordered_flat_set` and `boost::unordered_flat_map` can
+be efficiently move-constructed from `boost::concurrent_flat_set` and `boost::concurrent_flat_map`,
+respectively, and vice versa.
+This interoperability comes handy in multistage scenarios where parts of the data processing happen
+in parallel whereas other steps are non-concurrent (or non-modifying). In the following example,
+we want to construct a histogram from a huge input vector of words:
+the population phase can be done in parallel with `boost::concurrent_flat_map` and results
+then transferred to the final container.
+
+[source,c++]
+----
+std::vector<std::string> words = ...;
+
+// Insert words in parallel
+boost::concurrent_flat_map<std::string_view, std::size_t> m0;
+std::for_each(
+  std::execution::par, words.begin(), words.end(),
+  [&](const auto& word) {
+    m0.try_emplace_or_visit(word, 1, [](auto& x) { ++x.second; });
+  });
+
+// Transfer to a regular unordered_flat_map
+boost::unordered_flat_map m=std::move(m0);
+----

doc/unordered/concurrent_flat_map.adoc

@@ -50,6 +50,9 @@ namespace boost {
     using size_type            = std::size_t;
     using difference_type      = std::ptrdiff_t;
 
+    // constants
+    static constexpr size_type xref:#concurrent_flat_map_constants[bulk_visit_size] = _implementation-defined_;
+
     // construct/copy/destroy
     xref:#concurrent_flat_map_default_constructor[concurrent_flat_map]();
     explicit xref:#concurrent_flat_map_bucket_count_constructor[concurrent_flat_map](size_type n,
@@ -69,6 +72,7 @@ namespace boost {
     explicit xref:#concurrent_flat_map_allocator_constructor[concurrent_flat_map](const Allocator& a);
     xref:#concurrent_flat_map_copy_constructor_with_allocator[concurrent_flat_map](const concurrent_flat_map& other, const Allocator& a);
     xref:#concurrent_flat_map_move_constructor_with_allocator[concurrent_flat_map](concurrent_flat_map&& other, const Allocator& a);
+    xref:#concurrent_flat_map_move_constructor_from_unordered_flat_map[concurrent_flat_map](unordered_flat_map<Key, T, Hash, Pred, Allocator>&& other);
     xref:#concurrent_flat_map_initializer_list_constructor[concurrent_flat_map](std::initializer_list<value_type> il,
                         size_type n = _implementation-defined_
                         const hasher& hf = hasher(),
@@ -89,9 +93,10 @@ namespace boost {
                         const allocator_type& a);
     xref:#concurrent_flat_map_destructor[~concurrent_flat_map]();
     concurrent_flat_map& xref:#concurrent_flat_map_copy_assignment[operator++=++](const concurrent_flat_map& other);
-    concurrent_flat_map& xref:#concurrent_flat_map_move_assignment[operator++=++](concurrent_flat_map&& other)
-      noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-              boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+    concurrent_flat_map& xref:#concurrent_flat_map_move_assignment[operator++=++](concurrent_flat_map&& other) ++noexcept(
+      (boost::allocator_traits<Allocator>::is_always_equal::value ||
+       boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+       std::is_same<pointer, value_type*>::value);++
     concurrent_flat_map& xref:#concurrent_flat_map_initializer_list_assignment[operator++=++](std::initializer_list<value_type>);
     allocator_type xref:#concurrent_flat_map_get_allocator[get_allocator]() const noexcept;
 
@@ -104,6 +109,13 @@ namespace boost {
     template<class K, class F> size_t xref:#concurrent_flat_map_cvisit[visit](const K& k, F f) const;
     template<class K, class F> size_t xref:#concurrent_flat_map_cvisit[cvisit](const K& k, F f) const;
 
+    template<class FwdIterator, class F>
+      size_t xref:concurrent_flat_map_bulk_visit[visit](FwdIterator first, FwdIterator last, F f);
+    template<class FwdIterator, class F>
+      size_t xref:concurrent_flat_map_bulk_visit[visit](FwdIterator first, FwdIterator last, F f) const;
+    template<class FwdIterator, class F>
+      size_t xref:concurrent_flat_map_bulk_visit[cvisit](FwdIterator first, FwdIterator last, F f) const;
+
     template<class F> size_t xref:#concurrent_flat_map_cvisit_all[visit_all](F f);
     template<class F> size_t xref:#concurrent_flat_map_cvisit_all[visit_all](F f) const;
     template<class F> size_t xref:#concurrent_flat_map_cvisit_all[cvisit_all](F f) const;
@@ -114,6 +126,16 @@ namespace boost {
     template<class ExecutionPolicy, class F>
       void xref:#concurrent_flat_map_parallel_cvisit_all[cvisit_all](ExecutionPolicy&& policy, F f) const;
 
+    template<class F> bool xref:#concurrent_flat_map_cvisit_while[visit_while](F f);
+    template<class F> bool xref:#concurrent_flat_map_cvisit_while[visit_while](F f) const;
+    template<class F> bool xref:#concurrent_flat_map_cvisit_while[cvisit_while](F f) const;
+    template<class ExecutionPolicy, class F>
+      bool xref:#concurrent_flat_map_parallel_cvisit_while[visit_while](ExecutionPolicy&& policy, F f);
+    template<class ExecutionPolicy, class F>
+      bool xref:#concurrent_flat_map_parallel_cvisit_while[visit_while](ExecutionPolicy&& policy, F f) const;
+    template<class ExecutionPolicy, class F>
+      bool xref:#concurrent_flat_map_parallel_cvisit_while[cvisit_while](ExecutionPolicy&& policy, F f) const;
+
     // capacity
     ++[[nodiscard]]++ bool xref:#concurrent_flat_map_empty[empty]() const noexcept;
     size_type xref:#concurrent_flat_map_size[size]() const noexcept;
@@ -305,8 +327,7 @@ https://en.cppreference.com/w/cpp/named_req/Erasable[Erasable^] from the table.
 
 |_Allocator_
 |An allocator whose value type is the same as the table's value type.
-`std::allocator_traits<Allocator>::pointer` and `std::allocator_traits<Allocator>::const_pointer`
-must be convertible to/from `value_type*` and `const value_type*`, respectively.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -364,6 +385,25 @@ if concurrent outstanding operations on `y` do not access `x` directly or indire
 
 ---
 
+=== Configuration Macros
+
+==== `BOOST_UNORDERED_DISABLE_REENTRANCY_CHECK`
+
+In debug builds (more precisely, when
+link:../../../assert/doc/html/assert.html#boost_assert_is_void[`BOOST_ASSERT_IS_VOID`^]
+is not defined), __container reentrancies__ (illegaly invoking an operation on `m` from within
+a function visiting elements of `m`) are detected and signalled through `BOOST_ASSERT_MSG`.
+When run-time speed is a concern, the feature can be disabled by globally defining
+this macro.
+
+=== Constants
+
+```cpp
+static constexpr size_type bulk_visit_size;
+```
+
+Chunk size internally used in xref:concurrent_flat_map_bulk_visit[bulk visit] operations.
+
 === Constructors
 
 ==== Default Constructor
@@ -491,6 +531,21 @@ Concurrency:;; Blocking on `other`.
 
 ---
 
+==== Move Constructor from unordered_flat_map
+
+```c++
+concurrent_flat_map(unordered_flat_map<Key, T, Hash, Pred, Allocator>&& other);
+```
+
+Move construction from a xref:#unordered_flat_map[`unordered_flat_map`].
+The internal bucket array of `other` is transferred directly to the new container.
+The hash function, predicate and allocator are moved-constructed from `other`.
+
+[horizontal]
+Complexity:;; O(`bucket_count()`) 
+
+---
+
 ==== Initializer List Constructor
 [source,c++,subs="+quotes"]
 ----
@@ -635,8 +690,9 @@ Concurrency:;; Blocking on `*this` and `other`.
 ==== Move Assignment
 ```c++
 concurrent_flat_map& operator=(concurrent_flat_map&& other)
-  noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-           boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+  noexcept((boost::allocator_traits<Allocator>::is_always_equal::value ||
+            boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+            std::is_same<pointer, value_type*>::value);
 ```
 The move assignment operator. Destroys previously existing elements, swaps the hash function and predicate from `other`,
 and move-assigns the allocator from `other` if `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`.
@@ -683,6 +739,42 @@ Notes:;; The `template<class K, class F>` overloads only participate in overload
 
 ---
 
+==== Bulk visit
+
+```c++
+template<class FwdIterator, class F>
+  size_t visit(FwdIterator first, FwdIterator last, F f);
+template<class FwdIterator, class F>
+  size_t visit(FwdIterator first, FwdIterator last, F f) const;
+template<class FwdIterator, class F>
+  size_t cvisit(FwdIterator first, FwdIterator last, F f) const;
+```
+
+For each element `k` in the range [`first`, `last`),
+if there is an element `x` in the container with key equivalent to `k`,
+invokes `f` with a reference to `x`.
+Such reference is const iff `*this` is const.
+
+Although functionally equivalent to individually invoking
+xref:concurrent_flat_map_cvisit[`[c\]visit`] for each key, bulk visitation
+performs generally faster due to internal streamlining optimizations.
+It is advisable that `std::distance(first,last)` be at least
+xref:#concurrent_flat_map_constants[`bulk_visit_size`] to enjoy
+a performance gain: beyond this size, performance is not expected
+to increase further.
+
+[horizontal]
+Requires:;; `FwdIterator` is a https://en.cppreference.com/w/cpp/named_req/ForwardIterator[LegacyForwardIterator^]
+({cpp}11 to {cpp}17), 
+or satisfies https://en.cppreference.com/w/cpp/iterator/forward_iterator[std::forward_iterator^] ({cpp}20 and later).
+For `K` = `std::iterator_traits<FwdIterator>::value_type`, either `K` is `key_type` or
+else `Hash::is_transparent` and `Pred::is_transparent` are valid member typedefs.
+In the latter case, the library assumes that `Hash` is callable with both `K` and `Key` and that `Pred` is transparent.
+This enables heterogeneous lookup which avoids the cost of instantiating an instance of the `Key` type.
+Returns:;; The number of elements visited.
+
+---
+
 ==== [c]visit_all
 
 ```c++
@@ -720,6 +812,50 @@ Unsequenced execution policies are not allowed.
 
 ---
 
+==== [c]visit_while
+
+```c++
+template<class F> bool visit_while(F f);
+template<class F> bool visit_while(F f) const;
+template<class F> bool cvisit_while(F f) const;
+```
+
+Successively invokes `f` with references to each of the elements in the table until `f` returns `false`
+or all the elements are visited.
+Such references to the elements are const iff `*this` is const.
+
+[horizontal]
+Returns:;; `false` iff `f` ever returns `false`.
+
+---
+
+==== Parallel [c]visit_while
+
+```c++
+template<class ExecutionPolicy, class F> bool visit_while(ExecutionPolicy&& policy, F f);
+template<class ExecutionPolicy, class F> bool visit_while(ExecutionPolicy&& policy, F f) const;
+template<class ExecutionPolicy, class F> bool cvisit_while(ExecutionPolicy&& policy, F f) const;
+```
+
+Invokes `f` with references to each of the elements in the table until `f` returns `false`
+or all the elements are visited.
+Such references to the elements are const iff `*this` is const.
+Execution is parallelized according to the semantics of the execution policy specified.
+
+[horizontal]
+Returns:;; `false` iff `f` ever returns `false`.
+Throws:;; Depending on the exception handling mechanism of the execution policy used, may call `std::terminate` if an exception is thrown within `f`.
+Notes:;; Only available in compilers supporting C++17 parallel algorithms. +
++
+These overloads only participate in overload resolution if `std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>>` is `true`. +
++
+Unsequenced execution policies are not allowed. +
++
+Parallelization implies that execution does not necessary finish as soon as `f` returns `false`, and as a result
+`f` may be invoked with further elements for which the return value is also `false`.
+
+---
+
 === Size and Capacity
 
 ==== empty
@@ -962,13 +1098,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 unlike xref:#concurrent_flat_map_emplace[emplace], which simply forwards all arguments to ``value_type``'s constructor.
@@ -1010,13 +1146,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first four overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // last two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 Invalidates pointers and references to elements if a rehashing is issued.
@@ -1038,19 +1174,19 @@ template<class K, class M> bool insert_or_assign(K&& k, M&& obj);
 
 Inserts a new element into the table or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the table as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 [horizontal]
@@ -1436,3 +1572,33 @@ Equivalent to
 -----
 c.xref:#concurrent_flat_map_erase_if[erase_if](pred);
 -----
+
+=== Serialization
+
+``concurrent_flat_map``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an concurrent_flat_map to an archive
+
+Saves all the elements of a `concurrent_flat_map` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `std::remove_const<key_type>::type` and `std::remove_const<mapped_type>::type`
+are serializable (XML serializable), and they do support Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+Concurrency:;; Blocking on `x`.
+
+---
+
+==== Loading an concurrent_flat_map from an archive
+
+Deletes all preexisting elements of a `concurrent_flat_map` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `concurrent_flat_map` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `x.key_equal()` is functionally equivalent to `other.key_equal()`.
+Concurrency:;; Blocking on `x`.

doc/unordered/intro.adoc

@@ -44,7 +44,8 @@ boost::unordered_flat_map
 
 ^.^h|*Concurrent*
 ^|
-^| `boost::concurrent_flat_map`
+^| `boost::concurrent_flat_set` +
+`boost::concurrent_flat_map`
 
 |===
 
@@ -56,9 +57,8 @@ in the market within the technical constraints imposed by the required standard
 interface to accommodate the implementation.
 There are two variants: **flat** (the fastest) and **node-based**, which 
 provide pointer stability under rehashing at the expense of being slower.
-* Finally, `boost::concurrent_flat_map` (the only **concurrent container** provided
-at present) is a hashmap designed and implemented to be used in high-performance
-multithreaded scenarios. Its interface is radically different from that of regular C++ containers.
+* Finally, **concurrent containers** are designed and implemented to be used in high-performance
+multithreaded scenarios. Their interface is radically different from that of regular C++ containers.
 
 All sets and maps in Boost.Unordered are instantiatied similarly as
 `std::unordered_set` and `std::unordered_map`, respectively:
@@ -73,6 +73,7 @@ namespace boost {
         class Alloc = std::allocator<Key> >
     class unordered_set; 
     // same for unordered_multiset, unordered_flat_set, unordered_node_set
+    // and concurrent_flat_set
 
     template <
         class Key, class Mapped,

doc/unordered/rationale.adoc

@@ -121,20 +121,21 @@ for Visual Studio on an x64-mode Intel CPU with SSE2 and for GCC on an IBM s390x
 == Concurrent Containers
 
 The same data structure used by Boost.Unordered open-addressing containers has been chosen
-also as the foundation of `boost::concurrent_flat_map`:
+also as the foundation of `boost::concurrent_flat_set` and `boost::concurrent_flat_map`:
 
 * Open-addressing is faster than closed-addressing alternatives, both in non-concurrent and
 concurrent scenarios.
 * Open-addressing layouts are eminently suitable for concurrent access and modification
 with minimal locking. In particular, the metadata array can be used for implementations of
 lookup that are lock-free up to the last step of actual element comparison.
-* Layout compatibility with Boost.Unordered flat containers allows for fast transfer
-of all elements between `boost::concurrent_flat_map` and `boost::unordered_flat_map`.
-(This feature has not been implemented yet.)
+* Layout compatibility with Boost.Unordered flat containers allows for 
+xref:#concurrent_interoperability_with_non_concurrent_containers[fast transfer]
+of all elements between `boost::concurrent_flat_map` and `boost::unordered_flat_map`,
+and vice versa.
 
 === Hash Function and Platform Interoperability
 
-`boost::concurrent_flat_map` makes the same decisions and provides the same guarantees
+Concurrent containers make the same decisions and provide the same guarantees
 as Boost.Unordered open-addressing containers with regards to 
 xref:#rationale_hash_function[hash function defaults] and
 xref:#rationale_platform_interoperability[platform interoperability].

doc/unordered/ref.adoc

@@ -11,3 +11,4 @@ include::unordered_flat_set.adoc[]
 include::unordered_node_map.adoc[]
 include::unordered_node_set.adoc[]
 include::concurrent_flat_map.adoc[]
+include::concurrent_flat_set.adoc[]

doc/unordered/structures.adoc

@@ -67,8 +67,8 @@ xref:#rationale_closed_addressing_containers[corresponding section].
 
 == Open-addressing Containers
 
-The diagram shows the basic internal layout of `boost::unordered_flat_map`/`unordered_node_map` and
-`boost:unordered_flat_set`/`unordered_node_set`.
+The diagram shows the basic internal layout of `boost::unordered_flat_set`/`unordered_node_set` and
+`boost:unordered_flat_map`/`unordered_node_map`.
 
 
 [#img-foa-layout]
@@ -76,7 +76,7 @@ The diagram shows the basic internal layout of `boost::unordered_flat_map`/`unor
 image::foa.png[align=center]
 
 As with all open-addressing containers, elements (or pointers to the element nodes in the case of
-`boost::unordered_node_map` and `boost::unordered_node_set`) are stored directly in the bucket array.
+`boost::unordered_node_set` and `boost::unordered_node_map`) are stored directly in the bucket array.
 This array is logically divided into 2^_n_^ _groups_ of 15 elements each.
 In addition to the bucket array, there is an associated _metadata array_ with 2^_n_^
 16-byte words.
@@ -129,7 +129,7 @@ xref:#rationale_open_addresing_containers[corresponding section].
 
 == Concurrent Containers
 
-`boost::concurrent_flat_map` uses the basic
+`boost::concurrent_flat_set` and `boost::concurrent_flat_map` use the basic
 xref:#structures_open_addressing_containers[open-addressing layout] described above
 augmented with synchronization mechanisms.
 

doc/unordered/unordered_flat_map.adoc

@@ -77,6 +77,7 @@ namespace boost {
     explicit xref:#unordered_flat_map_allocator_constructor[unordered_flat_map](const Allocator& a);
     xref:#unordered_flat_map_copy_constructor_with_allocator[unordered_flat_map](const unordered_flat_map& other, const Allocator& a);
     xref:#unordered_flat_map_move_constructor_with_allocator[unordered_flat_map](unordered_flat_map&& other, const Allocator& a);
+    xref:#unordered_flat_map_move_constructor_from_concurrent_flat_map[unordered_flat_map](concurrent_flat_map<Key, T, Hash, Pred, Allocator>&& other);
     xref:#unordered_flat_map_initializer_list_constructor[unordered_flat_map](std::initializer_list<value_type> il,
                        size_type n = _implementation-defined_
                        const hasher& hf = hasher(),
@@ -96,9 +97,10 @@ namespace boost {
                        const allocator_type& a);
     xref:#unordered_flat_map_destructor[~unordered_flat_map]();
     unordered_flat_map& xref:#unordered_flat_map_copy_assignment[operator++=++](const unordered_flat_map& other);
-    unordered_flat_map& xref:#unordered_flat_map_move_assignment[operator++=++](unordered_flat_map&& other)
-      noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-              boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+    unordered_flat_map& xref:#unordered_flat_map_move_assignment[operator++=++](unordered_flat_map&& other) ++noexcept(
+      (boost::allocator_traits<Allocator>::is_always_equal::value ||
+       boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+       std::is_same<pointer, value_type*>::value);++
     unordered_flat_map& xref:#unordered_flat_map_initializer_list_assignment[operator++=++](std::initializer_list<value_type>);
     allocator_type xref:#unordered_flat_map_get_allocator[get_allocator]() const noexcept;
 
@@ -311,8 +313,7 @@ https://en.cppreference.com/w/cpp/named_req/Erasable[Erasable^] from the contain
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
-`std::allocator_traits<Allocator>::pointer` and `std::allocator_traits<Allocator>::const_pointer`
-must be convertible to/from `value_type*` and `const value_type*`, respectively.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -472,6 +473,22 @@ from `other`, and the allocator is copy-constructed from `a`.
 
 ---
 
+==== Move Constructor from concurrent_flat_map
+
+```c++
+unordered_flat_map(concurrent_flat_map<Key, T, Hash, Pred, Allocator>&& other);
+```
+
+Move construction from a xref:#concurrent_flat_map[`concurrent_flat_map`].
+The internal bucket array of `other` is transferred directly to the new container.
+The hash function, predicate and allocator are moved-constructed from `other`.
+
+[horizontal]
+Complexity:;; Constant time.
+Concurrency:;; Blocking on `other`.
+
+---
+
 ==== Initializer List Constructor
 [source,c++,subs="+quotes"]
 ----
@@ -615,8 +632,9 @@ Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/CopyInse
 ==== Move Assignment
 ```c++
 unordered_flat_map& operator=(unordered_flat_map&& other)
-  noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-           boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+  noexcept((boost::allocator_traits<Allocator>::is_always_equal::value ||
+            boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+            std::is_same<pointer, value_type*>::value);
 ```
 The move assignment operator. Destroys previously existing elements, swaps the hash function and predicate from `other`,
 and move-assigns the allocator from `other` if `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`.
@@ -891,13 +909,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 unlike xref:#unordered_flat_map_emplace[emplace], which simply forwards all arguments to ``value_type``'s constructor.
@@ -936,13 +954,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 unlike xref:#unordered_flat_map_emplace_hint[emplace_hint], which simply forwards all arguments to ``value_type``'s constructor.
@@ -967,19 +985,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 [horizontal]
@@ -1005,19 +1023,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 `hint` is a suggestion to where the element should be inserted. This implementation ignores it.
@@ -1308,7 +1326,7 @@ void rehash(size_type n);
 
 Changes if necessary the size of the bucket array so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
 
-When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array. If the provided Allocator uses fancy pointers, a default allocation is subsequently performed.
 
 Invalidates iterators, pointers and references, and changes the order of elements.
 
@@ -1447,4 +1465,54 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_flat_map``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_flat_map to an archive
+
+Saves all the elements of an `unordered_flat_map` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `std::remove_const<key_type>::type` and `std::remove_const<mapped_type>::type`
+are serializable (XML serializable), and they do support Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_flat_map from an archive
+
+Deletes all preexisting elements of an `unordered_flat_map` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_flat_map` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `x.key_equal()` is functionally equivalent to `other.key_equal()`.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_flat_map` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_flat_map` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_flat_set.adoc

@@ -71,7 +71,7 @@ namespace boost {
       xref:#unordered_flat_set_iterator_range_constructor_with_allocator[unordered_flat_set](InputIterator f, InputIterator l, const allocator_type& a);
     explicit xref:#unordered_flat_set_allocator_constructor[unordered_flat_set](const Allocator& a);
     xref:#unordered_flat_set_copy_constructor_with_allocator[unordered_flat_set](const unordered_flat_set& other, const Allocator& a);
-    xref:#unordered_flat_set_move_constructor_with_allocator[unordered_flat_set](unordered_flat_set&& other, const Allocator& a);
+    xref:#unordered_flat_set_move_constructor_from_concurrent_flat_set[unordered_flat_set](concurrent_flat_set<Key, Hash, Pred, Allocator>&& other);
     xref:#unordered_flat_set_initializer_list_constructor[unordered_flat_set](std::initializer_list<value_type> il,
                        size_type n = _implementation-defined_
                        const hasher& hf = hasher(),
@@ -91,9 +91,10 @@ namespace boost {
                        const allocator_type& a);
     xref:#unordered_flat_set_destructor[~unordered_flat_set]();
     unordered_flat_set& xref:#unordered_flat_set_copy_assignment[operator++=++](const unordered_flat_set& other);
-    unordered_flat_set& xref:#unordered_flat_set_move_assignment[operator++=++](unordered_flat_set&& other)
-      noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-               boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+    unordered_flat_set& xref:#unordered_flat_set_move_assignment[operator++=++](unordered_flat_set&& other) ++noexcept(
+      (boost::allocator_traits<Allocator>::is_always_equal::value ||
+       boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+       std::is_same<pointer, value_type*>::value);++
     unordered_flat_set& xref:#unordered_flat_set_initializer_list_assignment[operator++=++](std::initializer_list<value_type>);
     allocator_type xref:#unordered_flat_set_get_allocator[get_allocator]() const noexcept;
 
@@ -261,8 +262,7 @@ and https://en.cppreference.com/w/cpp/named_req/Erasable[Erasable^] from the con
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
-`std::allocator_traits<Allocator>::pointer` and `std::allocator_traits<Allocator>::const_pointer`
-must be convertible to/from `value_type*` and `const value_type*`, respectively.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -422,6 +422,22 @@ from `other`, and the allocator is copy-constructed from `a`.
 
 ---
 
+==== Move Constructor from concurrent_flat_set
+
+```c++
+unordered_flat_set(concurrent_flat_set<Key, Hash, Pred, Allocator>&& other);
+```
+
+Move construction from a xref:#concurrent_flat_set[`concurrent_flat_set`].
+The internal bucket array of `other` is transferred directly to the new container.
+The hash function, predicate and allocator are moved-constructed from `other`.
+
+[horizontal]
+Complexity:;; Constant time.
+Concurrency:;; Blocking on `other`.
+
+---
+
 ==== Initializer List Constructor
 [source,c++,subs="+quotes"]
 ----
@@ -565,8 +581,9 @@ Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/CopyInse
 ==== Move Assignment
 ```c++
 unordered_flat_set& operator=(unordered_flat_set&& other)
-  noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-           boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+  noexcept((boost::allocator_traits<Allocator>::is_always_equal::value ||
+            boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+            std::is_same<pointer, value_type*>::value);
 ```
 The move assignment operator. Destroys previously existing elements, swaps the hash function and predicate from `other`,
 and move-assigns the allocator from `other` if `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`.
@@ -1087,7 +1104,7 @@ void rehash(size_type n);
 
 Changes if necessary the size of the bucket array so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
 
-When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array. If the provided Allocator uses fancy pointers, a default allocation is subsequently performed.
 
 Invalidates iterators, pointers and references, and changes the order of elements.
 
@@ -1201,4 +1218,54 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_flat_set``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_flat_set to an archive
+
+Saves all the elements of an `unordered_flat_set` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `value_type`
+is serializable (XML serializable), and it supports Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_flat_set from an archive
+
+Deletes all preexisting elements of an `unordered_flat_set` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_flat_set` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `x.key_equal()` is functionally equivalent to `other.key_equal()`.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_flat_set` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_flat_set` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_map.adoc

@@ -26,12 +26,12 @@ namespace boost {
     using hasher               = Hash;
     using key_equal            = Pred;
     using allocator_type       = Allocator;
-    using pointer              = typename boost::allocator_traits<Allocator>::pointer;
-    using const_pointer        = typename boost::allocator_traits<Allocator>::const_pointer;
+    using pointer              = typename std::allocator_traits<Allocator>::pointer;
+    using const_pointer        = typename std::allocator_traits<Allocator>::const_pointer;
     using reference            = value_type&;
     using const_reference      = const value_type&;
-    using size_type            = _implementation-defined_;
-    using difference_type      = _implementation-defined_;
+    using size_type            = std::size_t;
+    using difference_type      = std::ptrdiff_t;
 
     using iterator             = _implementation-defined_;
     using const_iterator       = _implementation-defined_;
@@ -316,6 +316,7 @@ namespace boost {
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -323,51 +324,15 @@ The elements are organized into buckets. Keys with the same hash code are stored
 
 The number of buckets can be automatically increased by a call to insert, or as the result of calling rehash.
 
----
+=== Configuration macros
+
+==== `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+
+Globally define this macro to support loading of ``unordered_map``s saved to
+a Boost.Serialization archive with a version of Boost prior to Boost 1.84.
 
 === Typedefs
 
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::pointer pointer;
-----
-
-`value_type*` if `allocator_type::pointer` is not defined.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::const_pointer const_pointer;
-----
-
-`boost::pointer_to_other<pointer, value_type>::type` if `allocator_type::const_pointer` is not defined.
-
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ size_type;
-----
-
-An unsigned integral type.
-
-`size_type` can represent any non-negative value of `difference_type`.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ difference_type;
-----
-
-A signed integral type.
-
-Is identical to the difference type of `iterator` and `const_iterator`.
-
----
-
 [source,c++,subs=+quotes]
 ----
 typedef _implementation-defined_ iterator;
@@ -419,7 +384,8 @@ A const_local_iterator object can be used to iterate through a single bucket.
 typedef _implementation-defined_ node_type;
 ----
 
-See node_handle_map for details.
+A class for holding extracted container elements, modelling 
+https://en.cppreference.com/w/cpp/container/node_handle[NodeHandle].
 
 ---
 
@@ -428,7 +394,20 @@ See node_handle_map for details.
 typedef _implementation-defined_ insert_return_type;
 ----
 
-Structure returned by inserting node_type.
+A specialization of an internal class template:
+
+[source,c++,subs=+quotes]
+----
+template<class Iterator, class NodeType>
+struct _insert_return_type_ // name is exposition only
+{
+  Iterator position;
+  bool     inserted;
+  NodeType node;
+};
+----
+
+with `Iterator` = `iterator` and `NodeType` = `node_type`.
 
 ---
 
@@ -508,10 +487,7 @@ The move constructor.
 
 [horizontal]
 Notes:;; This is implemented using Boost.Move.
-Requires:;; `value_type` is move-constructible. +
-+
-On compilers without rvalue reference support the emulation does not support moving without calling `boost::move` if `value_type` is not copyable.
-So, for example, you can't return the container from a function.
+Requires:;; `value_type` is move-constructible.
 
 ---
 
@@ -711,7 +687,6 @@ The move assignment operator.
 If `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`, the allocator is overwritten, if not the moved elements are created using the existing allocator.
 
 [horizontal]
-Notes:;; On compilers without rvalue references, this is emulated using Boost.Move. Note that on some compilers the copy assignment operator may be used in some circumstances.
 Requires:;; `value_type` is move constructible.
 
 ---
@@ -822,11 +797,7 @@ If an insert took place, then the iterator points to the newly inserted element.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -847,11 +818,7 @@ Notes:;; The standard is fairly vague on the meaning of the hint. But the only p
 +
 Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to 10 arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -1029,13 +996,13 @@ Notes:;; This function is similiar to xref:#unordered_map_emplace[emplace] excep
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 instead of xref:#unordered_map_emplace[emplace] which simply forwards all arguments to ``value_type``'s constructor.
@@ -1045,10 +1012,6 @@ Can invalidate iterators, but only if the insert causes the load factor to be gr
 Pointers and references to elements are never invalidated.
 
 The `template<class K, class\... Args>` overload only participates in overload resolution if `Hash::is_transparent` and `Pred::is_transparent` are valid member typedefs and neither `iterator` nor `const_iterator` are implicitly convertible from `K`. The library assumes that `Hash` is callable with both `K` and `Key` and that `Pred` is transparent. This enables heterogeneous lookup which avoids the cost of instantiating an instance of the `Key` type.
-
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics.
-
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
 --
 
 ---
@@ -1078,13 +1041,13 @@ Notes:;; This function is similiar to xref:#unordered_map_emplace_hint[emplace_h
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 instead of xref:#unordered_map_emplace_hint[emplace_hint] which simply forwards all arguments to ``value_type``'s constructor.
@@ -1096,10 +1059,6 @@ Can invalidate iterators, but only if the insert causes the load factor to be gr
 Pointers and references to elements are never invalidated.
 
 The `template<class K, class\... Args>` overload only participates in overload resolution if `Hash::is_transparent` and `Pred::is_transparent` are valid member typedefs and neither `iterator` nor `const_iterator` are implicitly convertible from `K`. The library assumes that `Hash` is callable with both `K` and `Key` and that `Pred` is transparent. This enables heterogeneous lookup which avoids the cost of instantiating an instance of the `Key` type.
-
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics.
-
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
 --
 
 ---
@@ -1116,19 +1075,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 [horizontal]
@@ -1156,19 +1115,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 `hint` is a suggestion to where the element should be inserted.
@@ -1761,9 +1720,7 @@ template<class Key, class T, class Hash, class Pred, class Alloc>
 Return `true` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1777,9 +1734,7 @@ template<class Key, class T, class Hash, class Pred, class Alloc>
 Return `false` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 === Swap
 ```c++
@@ -1825,4 +1780,59 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_map``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_map to an archive
+
+Saves all the elements of an `unordered_map` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `std::remove_const<key_type>::type` and `std::remove_const<mapped_type>::type`
+are serializable (XML serializable), and they do support Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_map from an archive
+
+Deletes all preexisting elements of an `unordered_map` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_map` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/EmplaceConstructible[EmplaceConstructible^]
+from `(std::remove_const<key_type>::type&&, std::remove_const<mapped_type>::type&&)`.
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+Note:;; If the archive was saved using a release of Boost prior to Boost 1.84,
+the configuration macro `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+has to be globally defined for this operation to succeed; otherwise, an exception is thrown.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_map` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_map` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_multimap.adoc

@@ -26,12 +26,12 @@ namespace boost {
     using hasher               = Hash;
     using key_equal            = Pred;
     using allocator_type       = Allocator;
-    using pointer              = typename boost::allocator_traits<Allocator>::pointer;
-    using const_pointer        = typename boost::allocator_traits<Allocator>::const_pointer;
+    using pointer              = typename std::allocator_traits<Allocator>::pointer;
+    using const_pointer        = typename std::allocator_traits<Allocator>::const_pointer;
     using reference            = value_type&;
     using const_reference      = const value_type&;
-    using size_type            = _implementation-defined_;
-    using difference_type      = _implementation-defined_;
+    using size_type            = std::size_t;
+    using difference_type      = std::ptrdiff_t;
 
     using iterator             = _implementation-defined_;
     using const_iterator       = _implementation-defined_;
@@ -283,6 +283,7 @@ namespace boost {
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -290,49 +291,15 @@ The elements are organized into buckets. Keys with the same hash code are stored
 
 The number of buckets can be automatically increased by a call to insert, or as the result of calling rehash.
 
+=== Configuration macros
+
+==== `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+
+Globally define this macro to support loading of ``unordered_multimap``s saved to
+a Boost.Serialization archive with a version of Boost prior to Boost 1.84.
+
 === Typedefs
 
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::pointer pointer;
-----
-
-`value_type*` if `allocator_type::pointer` is not defined.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::const_pointer const_pointer;
-----
-
-`boost::pointer_to_other<pointer, value_type>::type` if `allocator_type::const_pointer` is not defined.
-
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ size_type;
-----
-
-An unsigned integral type.
-
-`size_type` can represent any non-negative value of `difference_type`.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ difference_type;
-----
-
-A signed integral type.
-
-Is identical to the difference type of `iterator` and `const_iterator`.
-
----
-
 [source,c++,subs=+quotes]
 ----
 typedef _implementation-defined_ iterator;
@@ -464,10 +431,7 @@ The move constructor.
 
 [horizontal]
 Notes:;; This is implemented using Boost.Move.
-Requires:;; `value_type` is move-constructible. +
-+
-On compilers without rvalue reference support the emulation does not support moving without calling `boost::move` if `value_type` is not copyable.
-So, for example, you can't return the container from a function.
+Requires:;; `value_type` is move-constructible.
 
 ---
 
@@ -666,7 +630,6 @@ The move assignment operator.
 If `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`, the allocator is overwritten, if not the moved elements are created using the existing allocator.
 
 [horizontal]
-Notes:;; On compilers without rvalue references, this is emulated using Boost.Move. Note that on some compilers the copy assignment operator may be used in some circumstances.
 Requires:;; `value_type` is move constructible.
 
 ---
@@ -775,11 +738,7 @@ Returns:;; An iterator pointing to the inserted element.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -800,11 +759,7 @@ Notes:;; The standard is fairly vague on the meaning of the hint. But the only p
 +
 Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to 10 arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -1486,9 +1441,7 @@ template<class Key, class T, class Hash, class Pred, class Alloc>
 Return `true` if `x.size() == y.size()` and for every equivalent key group in `x`, there is a group in `y` for the same key, which is a permutation (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1502,9 +1455,7 @@ template<class Key, class T, class Hash, class Pred, class Alloc>
 Return `false` if `x.size() == y.size()` and for every equivalent key group in `x`, there is a group in `y` for the same key, which is a permutation (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1552,4 +1503,59 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_multimap``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_multimap to an archive
+
+Saves all the elements of an `unordered_multimap` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `std::remove_const<key_type>::type` and `std::remove_const<mapped_type>::type`
+are serializable (XML serializable), and they do support Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_multimap from an archive
+
+Deletes all preexisting elements of an `unordered_multimap` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_multimap` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/EmplaceConstructible[EmplaceConstructible^]
+from `(std::remove_const<key_type>::type&&, std::remove_const<mapped_type>::type&&)`.
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+Note:;; If the archive was saved using a release of Boost prior to Boost 1.84,
+the configuration macro `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+has to be globally defined for this operation to succeed; otherwise, an exception is thrown.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_multimap` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_multimap` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_multiset.adoc

@@ -24,12 +24,12 @@ namespace boost {
     using hasher               = Hash;
     using key_equal            = Pred;
     using allocator_type       = Allocator;
-    using pointer              = typename boost::allocator_traits<Allocator>::pointer;
-    using const_pointer        = typename boost::allocator_traits<Allocator>::const_pointer;
+    using pointer              = typename std::allocator_traits<Allocator>::pointer;
+    using const_pointer        = typename std::allocator_traits<Allocator>::const_pointer;
     using reference            = value_type&;
     using const_reference      = const value_type&;
-    using size_type            = _implementation-defined_;
-    using difference_type      = _implementation-defined_;
+    using size_type            = std::size_t;
+    using difference_type      = std::ptrdiff_t;
 
     using iterator             = _implementation-defined_;
     using const_iterator       = _implementation-defined_;
@@ -271,6 +271,7 @@ namespace boost {
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -278,50 +279,15 @@ The elements are organized into buckets. Keys with the same hash code are stored
 
 The number of buckets can be automatically increased by a call to insert, or as the result of calling rehash.
 
----
+=== Configuration macros
+
+==== `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+
+Globally define this macro to support loading of ``unordered_multiset``s saved to
+a Boost.Serialization archive with a version of Boost prior to Boost 1.84.
 
 === Typedefs
 
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::pointer pointer;
-----
-
-`value_type*` if `allocator_type::pointer` is not defined.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::const_pointer const_pointer;
-----
-
-`boost::pointer_to_other<pointer, value_type>::type` if `allocator_type::const_pointer` is not defined.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ size_type;
-----
-
-An unsigned integral type.
-
-`size_type` can represent any non-negative value of `difference_type`.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ difference_type;
-----
-
-A signed integral type.
-
-Is identical to the difference type of `iterator` and `const_iterator`.
-
----
-
 [source,c++,subs=+quotes]
 ----
 typedef _implementation-defined_ iterator;
@@ -453,10 +419,7 @@ The move constructor.
 
 [horizontal]
 Notes:;; This is implemented using Boost.Move.
-Requires:;; `value_type` is move-constructible. +
-+
-On compilers without rvalue reference support the emulation does not support moving without calling `boost::move` if `value_type` is not copyable.
-So, for example, you can't return the container from a function.
+Requires:;; `value_type` is move-constructible.
 
 ---
 
@@ -656,7 +619,6 @@ The move assignment operator.
 If `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`, the allocator is overwritten, if not the moved elements are created using the existing allocator.
 
 [horizontal]
-Notes:;; On compilers without rvalue references, this is emulated using Boost.Move. Note that on some compilers the copy assignment operator may be used in some circumstances.
 Requires:;; `value_type` is move constructible.
 
 ---
@@ -767,11 +729,7 @@ Returns:;; An iterator pointing to the inserted element.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -792,11 +750,7 @@ Notes:;; The standard is fairly vague on the meaning of the hint. But the only p
 +
 Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to 10 arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -1419,9 +1373,7 @@ template<class Key, class Hash, class Pred, class Alloc>
 Return `true` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1435,9 +1387,7 @@ template<class Key, class Hash, class Pred, class Alloc>
 Return `false` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1485,4 +1435,58 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_multiset``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_multiset to an archive
+
+Saves all the elements of an `unordered_multiset` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `value_type`
+is serializable (XML serializable), and it supports Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_multiset from an archive
+
+Deletes all preexisting elements of an `unordered_multiset` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_multiset` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/MoveInsertable[MoveInsertable^].
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+Note:;; If the archive was saved using a release of Boost prior to Boost 1.84,
+the configuration macro `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+has to be globally defined for this operation to succeed; otherwise, an exception is thrown.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_multiset` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_multiset` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_node_map.adoc

@@ -95,9 +95,10 @@ namespace boost {
                        const allocator_type& a);
     xref:#unordered_node_map_destructor[~unordered_node_map]();
     unordered_node_map& xref:#unordered_node_map_copy_assignment[operator++=++](const unordered_node_map& other);
-    unordered_node_map& xref:#unordered_node_map_move_assignment[operator++=++](unordered_node_map&& other)
-      noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-              boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+    unordered_node_map& xref:#unordered_node_map_move_assignment[operator++=++](unordered_node_map&& other) ++noexcept(
+      (boost::allocator_traits<Allocator>::is_always_equal::value ||
+       boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+       std::is_same<pointer, value_type*>::value);++
     unordered_node_map& xref:#unordered_node_map_initializer_list_assignment[operator++=++](std::initializer_list<value_type>);
     allocator_type xref:#unordered_node_map_get_allocator[get_allocator]() const noexcept;
 
@@ -314,8 +315,7 @@ https://en.cppreference.com/w/cpp/named_req/Erasable[Erasable^] from the contain
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
-`std::allocator_traits<Allocator>::pointer` and `std::allocator_traits<Allocator>::const_pointer`
-must be convertible to/from `value_type*` and `const value_type*`, respectively.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -649,8 +649,9 @@ Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/CopyInse
 ==== Move Assignment
 ```c++
 unordered_node_map& operator=(unordered_node_map&& other)
-  noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-           boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+  noexcept((boost::allocator_traits<Allocator>::is_always_equal::value ||
+            boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+            std::is_same<pointer, value_type*>::value);
 ```
 The move assignment operator. Destroys previously existing elements, swaps the hash function and predicate from `other`,
 and move-assigns the allocator from `other` if `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`.
@@ -961,13 +962,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 unlike xref:#unordered_node_map_emplace[emplace], which simply forwards all arguments to ``value_type``'s constructor.
@@ -1006,13 +1007,13 @@ if there is an element with an equivalent key; otherwise, the construction is of
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<Args>(args)...))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<Args>(args)...))
 ```
 
 unlike xref:#unordered_node_map_emplace_hint[emplace_hint], which simply forwards all arguments to ``value_type``'s constructor.
@@ -1037,19 +1038,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 [horizontal]
@@ -1075,19 +1076,19 @@ template<class K, class M>
 
 Inserts a new element into the container or updates an existing one by assigning to the contained value.
 
-If there is an element with key `k`, then it is updated by assigning `boost::forward<M>(obj)`.
+If there is an element with key `k`, then it is updated by assigning `std::forward<M>(obj)`.
 
 If there is no such element, it is added to the container as:
 ```c++
 // first two overloads
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<Key>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<Key>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 
 // third overload
 value_type(std::piecewise_construct,
-           std::forward_as_tuple(boost::forward<K>(k)),
-           std::forward_as_tuple(boost::forward<M>(obj)))
+           std::forward_as_tuple(std::forward<K>(k)),
+           std::forward_as_tuple(std::forward<M>(obj)))
 ```
 
 `hint` is a suggestion to where the element should be inserted. This implementation ignores it.
@@ -1406,7 +1407,7 @@ void rehash(size_type n);
 
 Changes if necessary the size of the bucket array so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
 
-When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array. If the provided Allocator uses fancy pointers, a default allocation is subsequently performed.
 
 Invalidates iterators and changes the order of elements.
 
@@ -1545,4 +1546,57 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_node_map``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_node_map to an archive
+
+Saves all the elements of an `unordered_node_map` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `std::remove_const<key_type>::type` and `std::remove_const<mapped_type>::type`
+are serializable (XML serializable), and they do support Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_node_map from an archive
+
+Deletes all preexisting elements of an `unordered_node_map` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_node_map` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `key_type` and `mapped_type` are constructible from
+`std::remove_const<key_type>::type&&` and `std::remove_const<mapped_type>::type&&`,
+respectively.
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_node_map` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_node_map` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_node_set.adoc

@@ -90,9 +90,10 @@ namespace boost {
                        const allocator_type& a);
     xref:#unordered_node_set_destructor[~unordered_node_set]();
     unordered_node_set& xref:#unordered_node_set_copy_assignment[operator++=++](const unordered_node_set& other);
-    unordered_node_set& xref:#unordered_node_set_move_assignment[operator++=++](unordered_node_set&& other)
-      noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-              boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+    unordered_node_set& xref:#unordered_node_set_move_assignment[operator++=++](unordered_node_set&& other) ++noexcept(
+      (boost::allocator_traits<Allocator>::is_always_equal::value ||
+       boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+       std::is_same<pointer, value_type*>::value);++
     unordered_node_set& xref:#unordered_node_set_initializer_list_assignment[operator++=++](std::initializer_list<value_type>);
     allocator_type xref:#unordered_node_set_get_allocator[get_allocator]() const noexcept;
 
@@ -264,8 +265,7 @@ namespace boost {
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
-`std::allocator_traits<Allocator>::pointer` and `std::allocator_traits<Allocator>::const_pointer`
-must be convertible to/from `value_type*` and `const value_type*`, respectively.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -602,8 +602,9 @@ Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/CopyInse
 ==== Move Assignment
 ```c++
 unordered_node_set& operator=(unordered_node_set&& other)
-  noexcept(boost::allocator_traits<Allocator>::is_always_equal::value ||
-           boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value);
+  noexcept((boost::allocator_traits<Allocator>::is_always_equal::value ||
+            boost::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) &&
+            std::is_same<pointer, value_type*>::value);
 ```
 The move assignment operator. Destroys previously existing elements, swaps the hash function and predicate from `other`,
 and move-assigns the allocator from `other` if `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`.
@@ -1188,7 +1189,7 @@ void rehash(size_type n);
 
 Changes if necessary the size of the bucket array so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
 
-When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array. If the provided Allocator uses fancy pointers, a default allocation is subsequently performed.
 
 Invalidates iterators and changes the order of elements.
 
@@ -1302,4 +1303,55 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_node_set``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_node_set to an archive
+
+Saves all the elements of an `unordered_node_set` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `value_type`
+is serializable (XML serializable), and it supports Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_node_set from an archive
+
+Deletes all preexisting elements of an `unordered_node_set` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_node_set` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/MoveInsertable[MoveInsertable^].
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_node_set` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_node_set` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

doc/unordered/unordered_set.adoc

@@ -24,12 +24,12 @@ namespace boost {
     using hasher               = Hash;
     using key_equal            = Pred;
     using allocator_type       = Allocator;
-    using pointer              = typename boost::allocator_traits<Allocator>::pointer;
-    using const_pointer        = typename boost::allocator_traits<Allocator>::const_pointer;
+    using pointer              = typename std::allocator_traits<Allocator>::pointer;
+    using const_pointer        = typename std::allocator_traits<Allocator>::const_pointer;
     using reference            = value_type&;
     using const_reference      = const value_type&;
-    using size_type            = _implementation-defined_;
-    using difference_type      = _implementation-defined_;
+    using size_type            = std::size_t;
+    using difference_type      = std::ptrdiff_t;
 
     using iterator             = _implementation-defined_;
     using const_iterator       = _implementation-defined_;
@@ -272,6 +272,7 @@ namespace boost {
 
 |_Allocator_
 |An allocator whose value type is the same as the container's value type.
+Allocators using https://en.cppreference.com/w/cpp/named_req/Allocator#Fancy_pointers[fancy pointers] are supported.
 
 |===
 
@@ -279,51 +280,15 @@ The elements are organized into buckets. Keys with the same hash code are stored
 
 The number of buckets can be automatically increased by a call to insert, or as the result of calling rehash.
 
----
+=== Configuration macros
+
+==== `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+
+Globally define this macro to support loading of ``unordered_set``s saved to
+a Boost.Serialization archive with a version of Boost prior to Boost 1.84.
 
 === Typedefs
 
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::pointer pointer;
-----
-
-`value_type*` if `allocator_type::pointer` is not defined.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef typename allocator_type::const_pointer const_pointer;
-----
-
-`boost::pointer_to_other<pointer, value_type>::type` if `allocator_type::const_pointer` is not defined.
-
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ size_type;
-----
-
-An unsigned integral type.
-
-`size_type` can represent any non-negative value of `difference_type`.
-
----
-
-[source,c++,subs=+quotes]
-----
-typedef _implementation-defined_ difference_type;
-----
-
-A signed integral type.
-
-Is identical to the difference type of `iterator` and `const_iterator`.
-
----
-
 [source,c++,subs=+quotes]
 ----
 typedef _implementation-defined_ iterator;
@@ -375,7 +340,8 @@ A const_local_iterator object can be used to iterate through a single bucket.
 typedef _implementation-defined_ node_type;
 ----
 
-See node_handle_set for details.
+A class for holding extracted container elements, modelling 
+https://en.cppreference.com/w/cpp/container/node_handle[NodeHandle].
 
 ---
 
@@ -384,7 +350,20 @@ See node_handle_set for details.
 typedef _implementation-defined_ insert_return_type;
 ----
 
-Structure returned by inserting node_type.
+A specialization of an internal class template:
+
+[source,c++,subs=+quotes]
+----
+template<class Iterator, class NodeType>
+struct _insert_return_type_ // name is exposition only
+{
+  Iterator position;
+  bool     inserted;
+  NodeType node;
+};
+----
+
+with `Iterator` = `iterator` and `NodeType` = `node_type`.
 
 ---
 
@@ -464,10 +443,7 @@ The move constructor.
 
 [horizontal]
 Notes:;; This is implemented using Boost.Move.
-Requires:;; `value_type` is move-constructible. +
-+
-On compilers without rvalue reference support the emulation does not support moving without calling `boost::move` if `value_type` is not copyable.
-So, for example, you can't return the container from a function.
+Requires:;; `value_type` is move-constructible.
 
 ---
 
@@ -667,7 +643,6 @@ The move assignment operator.
 If `Alloc::propagate_on_container_move_assignment` exists and `Alloc::propagate_on_container_move_assignment::value` is `true`, the allocator is overwritten, if not the moved elements are created using the existing allocator.
 
 [horizontal]
-Notes:;; On compilers without rvalue references, this is emulated using Boost.Move. Note that on some compilers the copy assignment operator may be used in some circumstances.
 Requires:;; `value_type` is move constructible.
 
 ---
@@ -780,11 +755,7 @@ If an insert took place, then the iterator points to the newly inserted element.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to `10` arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -805,11 +776,7 @@ Notes:;; The standard is fairly vague on the meaning of the hint. But the only p
 +
 Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated. +
-+
-If the compiler doesn't support variadic template arguments or rvalue references, this is emulated for up to 10 arguments, with no support for rvalue references or move semantics. +
-+
-Since existing `std::pair` implementations don't support `std::piecewise_construct` this emulates it, but using `boost::unordered::piecewise_construct`.
+Pointers and references to elements are never invalidated.
 
 ---
 
@@ -1484,9 +1451,7 @@ template<class Key, class Hash, class Pred, class Alloc>
 Return `true` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1500,9 +1465,7 @@ template<class Key, class Hash, class Pred, class Alloc>
 Return `false` if `x.size() == y.size()` and for every element in `x`, there is an element in `y` with the same key, with an equal value (using `operator==` to compare the value types).
 
 [horizontal]
-Notes:;; The behavior of this function was changed to match the C++11 standard in Boost 1.48. +
-+
-Behavior is undefined if the two containers don't have equivalent equality predicates.
+Notes:;; Behavior is undefined if the two containers don't have equivalent equality predicates.
 
 ---
 
@@ -1550,4 +1513,58 @@ for (auto i = c.begin(), last = c.end(); i != last; ) {
 return original_size - c.size();
 ```
 
+=== Serialization
+
+``unordered_set``s can be archived/retrieved by means of
+link:../../../serialization/index.html[Boost.Serialization^] using the API provided
+by this library. Both regular and XML archives are supported. 
+
+==== Saving an unordered_set to an archive
+
+Saves all the elements of an `unordered_set` `x` to an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; `value_type`
+is serializable (XML serializable), and it supports Boost.Serialization
+`save_construct_data`/`load_construct_data` protocol (automatically suported by
+https://en.cppreference.com/w/cpp/named_req/DefaultConstructible[DefaultConstructible^]
+types).  
+
 ---
+
+==== Loading an unordered_set from an archive
+
+Deletes all preexisting elements of an `unordered_set` `x` and inserts
+from an archive (XML archive) `ar` restored copies of the elements of the
+original `unordered_set` `other` saved to the storage read by `ar`.
+
+[horizontal]
+Requires:;; `value_type` is https://en.cppreference.com/w/cpp/named_req/MoveInsertable[MoveInsertable^].
+`x.key_equal()` is functionally equivalent to `other.key_equal()`.
+Note:;; If the archive was saved using a release of Boost prior to Boost 1.84,
+the configuration macro `BOOST_UNORDERED_ENABLE_SERIALIZATION_COMPATIBILITY_V0`
+has to be globally defined for this operation to succeed; otherwise, an exception is thrown.
+
+---
+
+==== Saving an iterator/const_iterator to an archive
+
+Saves the positional information of an `iterator` (`const_iterator`) `it`
+to an archive (XML archive) `ar`. `it` can be and `end()` iterator.
+
+[horizontal]
+Requires:;; The `unordered_set` `x` pointed to by `it` has been previously saved to `ar`,
+and no modifying operations have been issued on `x` between saving of `x` and
+saving of `it`.
+
+---
+
+==== Loading an iterator/const_iterator from an archive
+
+Makes an `iterator` (`const_iterator`) `it` point to the restored position of
+the original `iterator` (`const_iterator`) saved to the storage read by
+an archive (XML archive) `ar`.
+
+[horizontal]
+Requires:;; If `x` is the `unordered_set` `it` points to, no modifying operations
+have been issued on `x` between loading of `x` and loading of `it`.

examples/case_insensitive.hpp

@@ -14,7 +14,7 @@
 #define BOOST_HASH_EXAMPLES_CASE_INSENSITIVE_HEADER
 
 #include <boost/algorithm/string/predicate.hpp>
-#include <boost/functional/hash.hpp>
+#include <boost/container_hash/hash.hpp>
 
 namespace hash_examples
 {

include/boost/unordered/concurrent_flat_map.hpp

@@ -1,6 +1,7 @@
-/* Fast open-addressing concurrent hash table.
+/* Fast open-addressing concurrent hashmap.
  *
  * Copyright 2023 Christian Mazakas.
+ * Copyright 2023 Joaquin M Lopez Munoz.
  * 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)
@@ -12,71 +13,20 @@
 #define BOOST_UNORDERED_CONCURRENT_FLAT_MAP_HPP
 
 #include <boost/unordered/concurrent_flat_map_fwd.hpp>
+#include <boost/unordered/detail/concurrent_static_asserts.hpp>
 #include <boost/unordered/detail/foa/concurrent_table.hpp>
 #include <boost/unordered/detail/foa/flat_map_types.hpp>
 #include <boost/unordered/detail/type_traits.hpp>
+#include <boost/unordered/unordered_flat_map_fwd.hpp>
 
 #include <boost/container_hash/hash.hpp>
 #include <boost/core/allocator_access.hpp>
-#include <boost/mp11/algorithm.hpp>
-#include <boost/mp11/list.hpp>
-#include <boost/type_traits/type_identity.hpp>
+#include <boost/core/serialization.hpp>
 
-#include <functional>
 #include <type_traits>
-#include <utility>
-
-#define BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)                             \
-  static_assert(boost::unordered::detail::is_invocable<F, value_type&>::value, \
-    "The provided Callable must be invocable with value_type&");
-
-#define BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)                       \
-  static_assert(                                                               \
-    boost::unordered::detail::is_invocable<F, value_type const&>::value,       \
-    "The provided Callable must be invocable with value_type const&");
-
-#if BOOST_CXX_VERSION >= 202002L
-
-#define BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(P)                           \
-  static_assert(!std::is_base_of<std::execution::parallel_unsequenced_policy,  \
-                  ExecPolicy>::value,                                          \
-    "ExecPolicy must be sequenced.");                                          \
-  static_assert(                                                               \
-    !std::is_base_of<std::execution::unsequenced_policy, ExecPolicy>::value,   \
-    "ExecPolicy must be sequenced.");
-
-#else
-
-#define BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(P)                           \
-  static_assert(!std::is_base_of<std::execution::parallel_unsequenced_policy,  \
-                  ExecPolicy>::value,                                          \
-    "ExecPolicy must be sequenced.");
-#endif
-
-#define BOOST_UNORDERED_COMMA ,
-
-#define BOOST_UNORDERED_LAST_ARG(Arg, Args)                                    \
-  mp11::mp_back<mp11::mp_list<Arg BOOST_UNORDERED_COMMA Args> >
-
-#define BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_INVOCABLE(Arg, Args)            \
-  BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(BOOST_UNORDERED_LAST_ARG(Arg, Args))
-
-#define BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_CONST_INVOCABLE(Arg, Args)      \
-  BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(                               \
-    BOOST_UNORDERED_LAST_ARG(Arg, Args))
 
 namespace boost {
   namespace unordered {
-    namespace detail {
-      template <class F, class... Args>
-      struct is_invocable
-          : std::is_constructible<std::function<void(Args...)>,
-              std::reference_wrapper<typename std::remove_reference<F>::type> >
-      {
-      };
-
-    } // namespace detail
-
     template <class Key, class T, class Hash, class Pred, class Allocator>
     class concurrent_flat_map
     {
@@ -84,10 +34,16 @@ namespace boost {
       template <class Key2, class T2, class Hash2, class Pred2,
         class Allocator2>
       friend class concurrent_flat_map;
+      template <class Key2, class T2, class Hash2, class Pred2,
+        class Allocator2>
+      friend class unordered_flat_map;
 
       using type_policy = detail::foa::flat_map_types<Key, T>;
 
-      detail::foa::concurrent_table<type_policy, Hash, Pred, Allocator> table_;
+      using table_type =
+        detail::foa::concurrent_table<type_policy, Hash, Pred, Allocator>;
+
+      table_type table_;
 
       template <class K, class V, class H, class KE, class A>
       bool friend operator==(concurrent_flat_map<K, V, H, KE, A> const& lhs,
@@ -97,6 +53,11 @@ namespace boost {
       friend typename concurrent_flat_map<K, V, H, KE, A>::size_type erase_if(
         concurrent_flat_map<K, V, H, KE, A>& set, Predicate pred);
 
+      template<class Archive, class K, class V, class H, class KE, class A>
+      friend void serialize(
+        Archive& ar, concurrent_flat_map<K, V, H, KE, A>& c,
+        unsigned int version);
+
     public:
       using key_type = Key;
       using mapped_type = T;
@@ -104,14 +65,15 @@ namespace boost {
       using init_type = typename type_policy::init_type;
       using size_type = std::size_t;
       using difference_type = std::ptrdiff_t;
-      using hasher = typename boost::type_identity<Hash>::type;
-      using key_equal = typename boost::type_identity<Pred>::type;
-      using allocator_type = typename boost::type_identity<Allocator>::type;
+      using hasher = typename boost::unordered::detail::type_identity<Hash>::type;
+      using key_equal = typename boost::unordered::detail::type_identity<Pred>::type;
+      using allocator_type = typename boost::unordered::detail::type_identity<Allocator>::type;
       using reference = value_type&;
       using const_reference = value_type const&;
       using pointer = typename boost::allocator_pointer<allocator_type>::type;
       using const_pointer =
         typename boost::allocator_const_pointer<allocator_type>::type;
+      static constexpr size_type bulk_visit_size = table_type::bulk_visit_size;
 
       concurrent_flat_map()
           : concurrent_flat_map(detail::foa::default_bucket_count)
@@ -223,6 +185,13 @@ namespace boost {
       {
       }
 
+
+      concurrent_flat_map(
+        unordered_flat_map<Key, T, Hash, Pred, Allocator>&& other)
+          : table_(std::move(other.table_))
+      {
+      }
+
       ~concurrent_flat_map() = default;
 
       concurrent_flat_map& operator=(concurrent_flat_map const& rhs)
@@ -231,10 +200,8 @@ namespace boost {
         return *this;
       }
 
-      concurrent_flat_map& operator=(concurrent_flat_map&& rhs)
-        noexcept(boost::allocator_is_always_equal<Allocator>::type::value ||
-                 boost::allocator_propagate_on_container_move_assignment<
-                   Allocator>::type::value)
+      concurrent_flat_map& operator=(concurrent_flat_map&& rhs) noexcept(
+        noexcept(std::declval<table_type&>() = std::declval<table_type&&>()))
       {
         table_ = std::move(rhs.table_);
         return *this;
@@ -305,6 +272,33 @@ namespace boost {
         return table_.visit(std::forward<K>(k), f);
       }
 
+      template<class FwdIterator, class F>
+      BOOST_FORCEINLINE
+      size_t visit(FwdIterator first, FwdIterator last, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(FwdIterator)
+        BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)
+        return table_.visit(first, last, f);
+      }
+
+      template<class FwdIterator, class F>
+      BOOST_FORCEINLINE
+      size_t visit(FwdIterator first, FwdIterator last, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(FwdIterator)
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(first, last, f);
+      }
+
+      template<class FwdIterator, class F>
+      BOOST_FORCEINLINE
+      size_t cvisit(FwdIterator first, FwdIterator last, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(FwdIterator)
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(first, last, f);
+      }
+
       template <class F> size_type visit_all(F f)
       {
         BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)
@@ -355,6 +349,56 @@ namespace boost {
       }
 #endif
 
+      template <class F> bool visit_while(F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)
+        return table_.visit_while(f);
+      }
+
+      template <class F> bool visit_while(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit_while(f);
+      }
+
+      template <class F> bool cvisit_while(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.cvisit_while(f);
+      }
+
+#if defined(BOOST_UNORDERED_PARALLEL_ALGORITHMS)
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        bool>::type
+      visit_while(ExecPolicy&& p, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        return table_.visit_while(p, f);
+      }
+
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        bool>::type
+      visit_while(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        return table_.visit_while(p, f);
+      }
+
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        bool>::type
+      cvisit_while(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        return table_.cvisit_while(p, f);
+      }
+#endif
+
       /// Modifiers
       ///
 
@@ -411,6 +455,7 @@ namespace boost {
       BOOST_FORCEINLINE auto insert_or_visit(Ty&& value, F f)
         -> decltype(table_.insert_or_visit(std::forward<Ty>(value), f))
       {
+        BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)
         return table_.insert_or_visit(std::forward<Ty>(value), f);
       }
 
@@ -465,7 +510,7 @@ namespace boost {
       void insert_or_cvisit(std::initializer_list<value_type> ilist, F f)
       {
         BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
-        this->insert_or_visit(ilist.begin(), ilist.end(), f);
+        this->insert_or_cvisit(ilist.begin(), ilist.end(), f);
       }
 
       template <class... Args> BOOST_FORCEINLINE bool emplace(Args&&... args)
@@ -662,7 +707,7 @@ namespace boost {
       float max_load_factor() const noexcept
       {
         return table_.max_load_factor();
-      };
+      }
       void max_load_factor(float) {}
       size_type max_load() const noexcept { return table_.max_load(); }
 
@@ -711,6 +756,13 @@ namespace boost {
       return c.table_.erase_if(pred);
     }
 
+    template<class Archive, class K, class V, class H, class KE, class A>
+    void serialize(
+      Archive& ar, concurrent_flat_map<K, V, H, KE, A>& c, unsigned int)
+    {
+      ar & core::make_nvp("table",c.table_);
+    }
+
 #if BOOST_UNORDERED_TEMPLATE_DEDUCTION_GUIDES
 
     template <class InputIterator,
@@ -720,10 +772,10 @@ namespace boost {
         std::equal_to<boost::unordered::detail::iter_key_t<InputIterator> >,
       class Allocator = std::allocator<
         boost::unordered::detail::iter_to_alloc_t<InputIterator> >,
-      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
-      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
-      class = boost::enable_if_t<detail::is_pred_v<Pred> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_pred_v<Pred> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(InputIterator, InputIterator,
       std::size_t = boost::unordered::detail::foa::default_bucket_count,
       Hash = Hash(), Pred = Pred(), Allocator = Allocator())
@@ -733,21 +785,21 @@ namespace boost {
         Allocator>;
 
     template <class Key, class T,
-      class Hash = boost::hash<boost::remove_const_t<Key> >,
-      class Pred = std::equal_to<boost::remove_const_t<Key> >,
+      class Hash = boost::hash<std::remove_const_t<Key> >,
+      class Pred = std::equal_to<std::remove_const_t<Key> >,
       class Allocator = std::allocator<std::pair<const Key, T> >,
-      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
-      class = boost::enable_if_t<detail::is_pred_v<Pred> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_pred_v<Pred> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(std::initializer_list<std::pair<Key, T> >,
       std::size_t = boost::unordered::detail::foa::default_bucket_count,
       Hash = Hash(), Pred = Pred(), Allocator = Allocator())
-      -> concurrent_flat_map<boost::remove_const_t<Key>, T, Hash, Pred,
+      -> concurrent_flat_map<std::remove_const_t<Key>, T, Hash, Pred,
         Allocator>;
 
     template <class InputIterator, class Allocator,
-      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(InputIterator, InputIterator, std::size_t, Allocator)
       -> concurrent_flat_map<
         boost::unordered::detail::iter_key_t<InputIterator>,
@@ -757,8 +809,8 @@ namespace boost {
         Allocator>;
 
     template <class InputIterator, class Allocator,
-      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(InputIterator, InputIterator, Allocator)
       -> concurrent_flat_map<
         boost::unordered::detail::iter_key_t<InputIterator>,
@@ -768,9 +820,9 @@ namespace boost {
         Allocator>;
 
     template <class InputIterator, class Hash, class Allocator,
-      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
-      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(
       InputIterator, InputIterator, std::size_t, Hash, Allocator)
       -> concurrent_flat_map<
@@ -780,25 +832,25 @@ namespace boost {
         Allocator>;
 
     template <class Key, class T, class Allocator,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(std::initializer_list<std::pair<Key, T> >, std::size_t,
-      Allocator) -> concurrent_flat_map<boost::remove_const_t<Key>, T,
-      boost::hash<boost::remove_const_t<Key> >,
-      std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+      Allocator) -> concurrent_flat_map<std::remove_const_t<Key>, T,
+      boost::hash<std::remove_const_t<Key> >,
+      std::equal_to<std::remove_const_t<Key> >, Allocator>;
 
     template <class Key, class T, class Allocator,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(std::initializer_list<std::pair<Key, T> >, Allocator)
-      -> concurrent_flat_map<boost::remove_const_t<Key>, T,
-        boost::hash<boost::remove_const_t<Key> >,
-        std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+      -> concurrent_flat_map<std::remove_const_t<Key>, T,
+        boost::hash<std::remove_const_t<Key> >,
+        std::equal_to<std::remove_const_t<Key> >, Allocator>;
 
     template <class Key, class T, class Hash, class Allocator,
-      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
-      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
     concurrent_flat_map(std::initializer_list<std::pair<Key, T> >, std::size_t,
-      Hash, Allocator) -> concurrent_flat_map<boost::remove_const_t<Key>, T,
-      Hash, std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+      Hash, Allocator) -> concurrent_flat_map<std::remove_const_t<Key>, T,
+      Hash, std::equal_to<std::remove_const_t<Key> >, Allocator>;
 
 #endif
 
@@ -807,12 +859,4 @@ namespace boost {
   using unordered::concurrent_flat_map;
 } // namespace boost
 
-#undef BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE
-#undef BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE
-#undef BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY
-#undef BOOST_UNORDERED_COMMA
-#undef BOOST_UNORDERED_LAST_ARG
-#undef BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_INVOCABLE
-#undef BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_CONST_INVOCABLE
-
 #endif // BOOST_UNORDERED_CONCURRENT_FLAT_MAP_HPP

include/boost/unordered/concurrent_flat_map_fwd.hpp

@@ -1,4 +1,4 @@
-/* Fast open-addressing concurrent hash table.
+/* Fast open-addressing concurrent hashmap.
  *
  * Copyright 2023 Christian Mazakas.
  * Distributed under the Boost Software License, Version 1.0.

include/boost/unordered/concurrent_flat_set.hpp

@@ -0,0 +1,718 @@
+/* Fast open-addressing concurrent hashset.
+ *
+ * Copyright 2023 Christian Mazakas.
+ * Copyright 2023 Joaquin M Lopez Munoz.
+ * 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 https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_CONCURRENT_FLAT_SET_HPP
+#define BOOST_UNORDERED_CONCURRENT_FLAT_SET_HPP
+
+#include <boost/unordered/concurrent_flat_set_fwd.hpp>
+#include <boost/unordered/detail/concurrent_static_asserts.hpp>
+#include <boost/unordered/detail/foa/concurrent_table.hpp>
+#include <boost/unordered/detail/foa/flat_set_types.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
+#include <boost/unordered/unordered_flat_set_fwd.hpp>
+
+#include <boost/container_hash/hash.hpp>
+#include <boost/core/allocator_access.hpp>
+#include <boost/core/serialization.hpp>
+
+#include <utility>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class Hash, class Pred, class Allocator>
+    class concurrent_flat_set
+    {
+    private:
+      template <class Key2, class Hash2, class Pred2, class Allocator2>
+      friend class concurrent_flat_set;
+      template <class Key2, class Hash2, class Pred2, class Allocator2>
+      friend class unordered_flat_set;
+
+      using type_policy = detail::foa::flat_set_types<Key>;
+
+      using table_type =
+        detail::foa::concurrent_table<type_policy, Hash, Pred, Allocator>;
+
+      table_type table_;
+
+      template <class K, class H, class KE, class A>
+      bool friend operator==(concurrent_flat_set<K, H, KE, A> const& lhs,
+        concurrent_flat_set<K, H, KE, A> const& rhs);
+
+      template <class K, class H, class KE, class A, class Predicate>
+      friend typename concurrent_flat_set<K, H, KE, A>::size_type erase_if(
+        concurrent_flat_set<K, H, KE, A>& set, Predicate pred);
+
+      template<class Archive, class K, class H, class KE, class A>
+      friend void serialize(
+        Archive& ar, concurrent_flat_set<K, H, KE, A>& c,
+        unsigned int version);
+
+    public:
+      using key_type = Key;
+      using value_type = typename type_policy::value_type;
+      using init_type = typename type_policy::init_type;
+      using size_type = std::size_t;
+      using difference_type = std::ptrdiff_t;
+      using hasher = typename boost::unordered::detail::type_identity<Hash>::type;
+      using key_equal = typename boost::unordered::detail::type_identity<Pred>::type;
+      using allocator_type = typename boost::unordered::detail::type_identity<Allocator>::type;
+      using reference = value_type&;
+      using const_reference = value_type const&;
+      using pointer = typename boost::allocator_pointer<allocator_type>::type;
+      using const_pointer =
+        typename boost::allocator_const_pointer<allocator_type>::type;
+      static constexpr size_type bulk_visit_size = table_type::bulk_visit_size;
+
+      concurrent_flat_set()
+          : concurrent_flat_set(detail::foa::default_bucket_count)
+      {
+      }
+
+      explicit concurrent_flat_set(size_type n, const hasher& hf = hasher(),
+        const key_equal& eql = key_equal(),
+        const allocator_type& a = allocator_type())
+          : table_(n, hf, eql, a)
+      {
+      }
+
+      template <class InputIterator>
+      concurrent_flat_set(InputIterator f, InputIterator l,
+        size_type n = detail::foa::default_bucket_count,
+        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+        const allocator_type& a = allocator_type())
+          : table_(n, hf, eql, a)
+      {
+        this->insert(f, l);
+      }
+
+      concurrent_flat_set(concurrent_flat_set const& rhs)
+          : table_(rhs.table_,
+              boost::allocator_select_on_container_copy_construction(
+                rhs.get_allocator()))
+      {
+      }
+
+      concurrent_flat_set(concurrent_flat_set&& rhs)
+          : table_(std::move(rhs.table_))
+      {
+      }
+
+      template <class InputIterator>
+      concurrent_flat_set(
+        InputIterator f, InputIterator l, allocator_type const& a)
+          : concurrent_flat_set(f, l, 0, hasher(), key_equal(), a)
+      {
+      }
+
+      explicit concurrent_flat_set(allocator_type const& a)
+          : table_(detail::foa::default_bucket_count, hasher(), key_equal(), a)
+      {
+      }
+
+      concurrent_flat_set(
+        concurrent_flat_set const& rhs, allocator_type const& a)
+          : table_(rhs.table_, a)
+      {
+      }
+
+      concurrent_flat_set(concurrent_flat_set&& rhs, allocator_type const& a)
+          : table_(std::move(rhs.table_), a)
+      {
+      }
+
+      concurrent_flat_set(std::initializer_list<value_type> il,
+        size_type n = detail::foa::default_bucket_count,
+        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+        const allocator_type& a = allocator_type())
+          : concurrent_flat_set(n, hf, eql, a)
+      {
+        this->insert(il.begin(), il.end());
+      }
+
+      concurrent_flat_set(size_type n, const allocator_type& a)
+          : concurrent_flat_set(n, hasher(), key_equal(), a)
+      {
+      }
+
+      concurrent_flat_set(
+        size_type n, const hasher& hf, const allocator_type& a)
+          : concurrent_flat_set(n, hf, key_equal(), a)
+      {
+      }
+
+      template <typename InputIterator>
+      concurrent_flat_set(
+        InputIterator f, InputIterator l, size_type n, const allocator_type& a)
+          : concurrent_flat_set(f, l, n, hasher(), key_equal(), a)
+      {
+      }
+
+      template <typename InputIterator>
+      concurrent_flat_set(InputIterator f, InputIterator l, size_type n,
+        const hasher& hf, const allocator_type& a)
+          : concurrent_flat_set(f, l, n, hf, key_equal(), a)
+      {
+      }
+
+      concurrent_flat_set(
+        std::initializer_list<value_type> il, const allocator_type& a)
+          : concurrent_flat_set(
+              il, detail::foa::default_bucket_count, hasher(), key_equal(), a)
+      {
+      }
+
+      concurrent_flat_set(std::initializer_list<value_type> il, size_type n,
+        const allocator_type& a)
+          : concurrent_flat_set(il, n, hasher(), key_equal(), a)
+      {
+      }
+
+      concurrent_flat_set(std::initializer_list<value_type> il, size_type n,
+        const hasher& hf, const allocator_type& a)
+          : concurrent_flat_set(il, n, hf, key_equal(), a)
+      {
+      }
+
+
+      concurrent_flat_set(
+        unordered_flat_set<Key, Hash, Pred, Allocator>&& other)
+          : table_(std::move(other.table_))
+      {
+      }
+
+      ~concurrent_flat_set() = default;
+
+      concurrent_flat_set& operator=(concurrent_flat_set const& rhs)
+      {
+        table_ = rhs.table_;
+        return *this;
+      }
+
+      concurrent_flat_set& operator=(concurrent_flat_set&& rhs)
+        noexcept(boost::allocator_is_always_equal<Allocator>::type::value ||
+                 boost::allocator_propagate_on_container_move_assignment<
+                   Allocator>::type::value)
+      {
+        table_ = std::move(rhs.table_);
+        return *this;
+      }
+
+      concurrent_flat_set& operator=(std::initializer_list<value_type> ilist)
+      {
+        table_ = ilist;
+        return *this;
+      }
+
+      /// Capacity
+      ///
+
+      size_type size() const noexcept { return table_.size(); }
+      size_type max_size() const noexcept { return table_.max_size(); }
+
+      BOOST_ATTRIBUTE_NODISCARD bool empty() const noexcept
+      {
+        return size() == 0;
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE size_type visit(key_type const& k, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(k, f);
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE size_type cvisit(key_type const& k, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(k, f);
+      }
+
+      template <class K, class F>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      visit(K&& k, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(std::forward<K>(k), f);
+      }
+
+      template <class K, class F>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      cvisit(K&& k, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(std::forward<K>(k), f);
+      }
+
+      template<class FwdIterator, class F>
+      BOOST_FORCEINLINE
+      size_t visit(FwdIterator first, FwdIterator last, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(FwdIterator)
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(first, last, f);
+      }
+
+      template<class FwdIterator, class F>
+      BOOST_FORCEINLINE
+      size_t cvisit(FwdIterator first, FwdIterator last, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(FwdIterator)
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit(first, last, f);
+      }
+
+      template <class F> size_type visit_all(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit_all(f);
+      }
+
+      template <class F> size_type cvisit_all(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.cvisit_all(f);
+      }
+
+#if defined(BOOST_UNORDERED_PARALLEL_ALGORITHMS)
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        void>::type
+      visit_all(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        table_.visit_all(p, f);
+      }
+
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        void>::type
+      cvisit_all(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        table_.cvisit_all(p, f);
+      }
+#endif
+
+      template <class F> bool visit_while(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.visit_while(f);
+      }
+
+      template <class F> bool cvisit_while(F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.cvisit_while(f);
+      }
+
+#if defined(BOOST_UNORDERED_PARALLEL_ALGORITHMS)
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        bool>::type
+      visit_while(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        return table_.visit_while(p, f);
+      }
+
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        bool>::type
+      cvisit_while(ExecPolicy&& p, F f) const
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        return table_.cvisit_while(p, f);
+      }
+#endif
+
+      /// Modifiers
+      ///
+
+      BOOST_FORCEINLINE bool insert(value_type const& obj)
+      {
+        return table_.insert(obj);
+      }
+
+      BOOST_FORCEINLINE bool insert(value_type&& obj)
+      {
+        return table_.insert(std::move(obj));
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        bool >::type
+      insert(K&& k)
+      {
+        return table_.try_emplace(std::forward<K>(k));
+      }
+
+      template <class InputIterator>
+      void insert(InputIterator begin, InputIterator end)
+      {
+        for (auto pos = begin; pos != end; ++pos) {
+          table_.emplace(*pos);
+        }
+      }
+
+      void insert(std::initializer_list<value_type> ilist)
+      {
+        this->insert(ilist.begin(), ilist.end());
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE bool insert_or_visit(value_type const& obj, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.insert_or_cvisit(obj, f);
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE bool insert_or_visit(value_type&& obj, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.insert_or_cvisit(std::move(obj), f);
+      }
+
+      template <class K, class F>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        bool >::type
+      insert_or_visit(K&& k, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.try_emplace_or_cvisit(std::forward<K>(k), f);
+      }
+
+      template <class InputIterator, class F>
+      void insert_or_visit(InputIterator first, InputIterator last, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        for (; first != last; ++first) {
+          table_.emplace_or_cvisit(*first, f);
+        }
+      }
+
+      template <class F>
+      void insert_or_visit(std::initializer_list<value_type> ilist, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        this->insert_or_cvisit(ilist.begin(), ilist.end(), f);
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE bool insert_or_cvisit(value_type const& obj, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.insert_or_cvisit(obj, f);
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE bool insert_or_cvisit(value_type&& obj, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.insert_or_cvisit(std::move(obj), f);
+      }
+
+      template <class K, class F>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        bool >::type
+      insert_or_cvisit(K&& k, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        return table_.try_emplace_or_cvisit(std::forward<K>(k), f);
+      }
+
+      template <class InputIterator, class F>
+      void insert_or_cvisit(InputIterator first, InputIterator last, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        for (; first != last; ++first) {
+          table_.emplace_or_cvisit(*first, f);
+        }
+      }
+
+      template <class F>
+      void insert_or_cvisit(std::initializer_list<value_type> ilist, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)
+        this->insert_or_cvisit(ilist.begin(), ilist.end(), f);
+      }
+
+      template <class... Args> BOOST_FORCEINLINE bool emplace(Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...);
+      }
+
+      template <class Arg, class... Args>
+      BOOST_FORCEINLINE bool emplace_or_visit(Arg&& arg, Args&&... args)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_CONST_INVOCABLE(Arg, Args...)
+        return table_.emplace_or_cvisit(
+          std::forward<Arg>(arg), std::forward<Args>(args)...);
+      }
+
+      template <class Arg, class... Args>
+      BOOST_FORCEINLINE bool emplace_or_cvisit(Arg&& arg, Args&&... args)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_CONST_INVOCABLE(Arg, Args...)
+        return table_.emplace_or_cvisit(
+          std::forward<Arg>(arg), std::forward<Args>(args)...);
+      }
+
+      BOOST_FORCEINLINE size_type erase(key_type const& k)
+      {
+        return table_.erase(k);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      erase(K&& k)
+      {
+        return table_.erase(std::forward<K>(k));
+      }
+
+      template <class F>
+      BOOST_FORCEINLINE size_type erase_if(key_type const& k, F f)
+      {
+        return table_.erase_if(k, f);
+      }
+
+      template <class K, class F>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value &&
+          !detail::is_execution_policy<K>::value,
+        size_type>::type
+      erase_if(K&& k, F f)
+      {
+        return table_.erase_if(std::forward<K>(k), f);
+      }
+
+#if defined(BOOST_UNORDERED_PARALLEL_ALGORITHMS)
+      template <class ExecPolicy, class F>
+      typename std::enable_if<detail::is_execution_policy<ExecPolicy>::value,
+        void>::type
+      erase_if(ExecPolicy&& p, F f)
+      {
+        BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(ExecPolicy)
+        table_.erase_if(p, f);
+      }
+#endif
+
+      template <class F> size_type erase_if(F f) { return table_.erase_if(f); }
+
+      void swap(concurrent_flat_set& other) noexcept(
+        boost::allocator_is_always_equal<Allocator>::type::value ||
+        boost::allocator_propagate_on_container_swap<Allocator>::type::value)
+      {
+        return table_.swap(other.table_);
+      }
+
+      void clear() noexcept { table_.clear(); }
+
+      template <typename H2, typename P2>
+      size_type merge(concurrent_flat_set<Key, H2, P2, Allocator>& x)
+      {
+        BOOST_ASSERT(get_allocator() == x.get_allocator());
+        return table_.merge(x.table_);
+      }
+
+      template <typename H2, typename P2>
+      size_type merge(concurrent_flat_set<Key, H2, P2, Allocator>&& x)
+      {
+        return merge(x);
+      }
+
+      BOOST_FORCEINLINE size_type count(key_type const& k) const
+      {
+        return table_.count(k);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      count(K const& k)
+      {
+        return table_.count(k);
+      }
+
+      BOOST_FORCEINLINE bool contains(key_type const& k) const
+      {
+        return table_.contains(k);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, bool>::type
+      contains(K const& k) const
+      {
+        return table_.contains(k);
+      }
+
+      /// Hash Policy
+      ///
+      size_type bucket_count() const noexcept { return table_.capacity(); }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      }
+      void max_load_factor(float) {}
+      size_type max_load() const noexcept { return table_.max_load(); }
+
+      void rehash(size_type n) { table_.rehash(n); }
+      void reserve(size_type n) { table_.reserve(n); }
+
+      /// Observers
+      ///
+      allocator_type get_allocator() const noexcept
+      {
+        return table_.get_allocator();
+      }
+
+      hasher hash_function() const { return table_.hash_function(); }
+      key_equal key_eq() const { return table_.key_eq(); }
+    };
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      return lhs.table_ == rhs.table_;
+    }
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      return !(lhs == rhs);
+    }
+
+    template <class Key, class Hash, class Pred, class Alloc>
+    void swap(concurrent_flat_set<Key, Hash, Pred, Alloc>& x,
+      concurrent_flat_set<Key, Hash, Pred, Alloc>& y)
+      noexcept(noexcept(x.swap(y)))
+    {
+      x.swap(y);
+    }
+
+    template <class K, class H, class P, class A, class Predicate>
+    typename concurrent_flat_set<K, H, P, A>::size_type erase_if(
+      concurrent_flat_set<K, H, P, A>& c, Predicate pred)
+    {
+      return c.table_.erase_if(pred);
+    }
+
+    template<class Archive, class K, class H, class KE, class A>
+    void serialize(
+      Archive& ar, concurrent_flat_set<K, H, KE, A>& c, unsigned int)
+    {
+      ar & core::make_nvp("table",c.table_);
+    }
+
+#if BOOST_UNORDERED_TEMPLATE_DEDUCTION_GUIDES
+
+    template <class InputIterator,
+      class Hash =
+        boost::hash<typename std::iterator_traits<InputIterator>::value_type>,
+      class Pred =
+        std::equal_to<typename std::iterator_traits<InputIterator>::value_type>,
+      class Allocator = std::allocator<
+        typename std::iterator_traits<InputIterator>::value_type>,
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_pred_v<Pred> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(InputIterator, InputIterator,
+      std::size_t = boost::unordered::detail::foa::default_bucket_count,
+      Hash = Hash(), Pred = Pred(), Allocator = Allocator())
+      -> concurrent_flat_set<
+        typename std::iterator_traits<InputIterator>::value_type, Hash, Pred,
+        Allocator>;
+
+    template <class T, class Hash = boost::hash<T>,
+      class Pred = std::equal_to<T>, class Allocator = std::allocator<T>,
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_pred_v<Pred> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(std::initializer_list<T>,
+      std::size_t = boost::unordered::detail::foa::default_bucket_count,
+      Hash = Hash(), Pred = Pred(), Allocator = Allocator())
+      -> concurrent_flat_set< T, Hash, Pred, Allocator>;
+
+    template <class InputIterator, class Allocator,
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(InputIterator, InputIterator, std::size_t, Allocator)
+      -> concurrent_flat_set<
+        typename std::iterator_traits<InputIterator>::value_type,
+        boost::hash<typename std::iterator_traits<InputIterator>::value_type>,
+        std::equal_to<typename std::iterator_traits<InputIterator>::value_type>,
+        Allocator>;
+
+    template <class InputIterator, class Allocator,
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(InputIterator, InputIterator, Allocator)
+      -> concurrent_flat_set<
+        typename std::iterator_traits<InputIterator>::value_type,
+        boost::hash<typename std::iterator_traits<InputIterator>::value_type>,
+        std::equal_to<typename std::iterator_traits<InputIterator>::value_type>,
+        Allocator>;
+
+    template <class InputIterator, class Hash, class Allocator,
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(
+      InputIterator, InputIterator, std::size_t, Hash, Allocator)
+      -> concurrent_flat_set<
+        typename std::iterator_traits<InputIterator>::value_type, Hash,
+        std::equal_to<typename std::iterator_traits<InputIterator>::value_type>,
+        Allocator>;
+
+    template <class T, class Allocator,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(std::initializer_list<T>, std::size_t, Allocator)
+      -> concurrent_flat_set<T, boost::hash<T>,std::equal_to<T>, Allocator>;
+
+    template <class T, class Allocator,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(std::initializer_list<T >, Allocator)
+      -> concurrent_flat_set<T, boost::hash<T>, std::equal_to<T>, Allocator>;
+
+    template <class T, class Hash, class Allocator,
+      class = std::enable_if_t<detail::is_hash_v<Hash> >,
+      class = std::enable_if_t<detail::is_allocator_v<Allocator> > >
+    concurrent_flat_set(std::initializer_list<T >, std::size_t,Hash, Allocator)
+      -> concurrent_flat_set<T, Hash, std::equal_to<T>, Allocator>;
+
+#endif
+
+  } // namespace unordered
+
+  using unordered::concurrent_flat_set;
+} // namespace boost
+
+#endif // BOOST_UNORDERED_CONCURRENT_FLAT_SET_HPP

include/boost/unordered/concurrent_flat_set_fwd.hpp

@@ -0,0 +1,55 @@
+/* Fast open-addressing concurrent hashset.
+ *
+ * Copyright 2023 Christian Mazakas.
+ * Copyright 2023 Joaquin M Lopez Munoz.
+ * 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 https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_CONCURRENT_FLAT_SET_FWD_HPP
+#define BOOST_UNORDERED_CONCURRENT_FLAT_SET_FWD_HPP
+
+#include <boost/container_hash/hash_fwd.hpp>
+
+#include <functional>
+#include <memory>
+
+namespace boost {
+  namespace unordered {
+
+    template <class Key, class Hash = boost::hash<Key>,
+      class Pred = std::equal_to<Key>,
+      class Allocator = std::allocator<Key> >
+    class concurrent_flat_set;
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      concurrent_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class Hash, class Pred, class Alloc>
+    void swap(concurrent_flat_set<Key, Hash, Pred, Alloc>& x,
+      concurrent_flat_set<Key, Hash, Pred, Alloc>& y)
+      noexcept(noexcept(x.swap(y)));
+
+    template <class K, class H, class P, class A, class Predicate>
+    typename concurrent_flat_set<K, H, P, A>::size_type erase_if(
+      concurrent_flat_set<K, H, P, A>& c, Predicate pred);
+
+  } // namespace unordered
+
+  using boost::unordered::concurrent_flat_set;
+  using boost::unordered::swap;
+  using boost::unordered::operator==;
+  using boost::unordered::operator!=;
+} // namespace boost
+
+#endif // BOOST_UNORDERED_CONCURRENT_FLAT_SET_FWD_HPP

include/boost/unordered/detail/archive_constructed.hpp

@@ -0,0 +1,71 @@
+/* Copyright 2023 Joaquin M Lopez Munoz.
+ * 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 https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_DETAIL_ARCHIVE_CONSTRUCTED_HPP
+#define BOOST_UNORDERED_DETAIL_ARCHIVE_CONSTRUCTED_HPP
+
+#include <boost/unordered/detail/opt_storage.hpp>
+
+#include <boost/config.hpp>
+#include <boost/core/no_exceptions_support.hpp>
+#include <boost/core/noncopyable.hpp>
+#include <boost/core/serialization.hpp>
+
+namespace boost{
+namespace unordered{
+namespace detail{
+
+/* constructs a stack-based object from a serialization archive */
+
+template<typename T>
+struct archive_constructed:private noncopyable
+{
+  template<class Archive>
+  archive_constructed(const char* name,Archive& ar,unsigned int version)
+  {
+    core::load_construct_data_adl(ar,std::addressof(get()),version);
+    BOOST_TRY{
+      ar>>core::make_nvp(name,get());
+    }
+    BOOST_CATCH(...){
+      get().~T();
+      BOOST_RETHROW;
+    }
+    BOOST_CATCH_END
+  }
+
+  ~archive_constructed()
+  {
+    get().~T();
+  }
+
+#if defined(BOOST_GCC)&&(BOOST_GCC>=4*10000+6*100)
+#define BOOST_UNORDERED_IGNORE_WSTRICT_ALIASING
+#endif
+
+#if defined(BOOST_UNORDERED_IGNORE_WSTRICT_ALIASING)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#endif
+
+  T& get(){return *space.address();}
+
+#if defined(BOOST_UNORDERED_IGNORE_WSTRICT_ALIASING)
+#pragma GCC diagnostic pop
+#undef BOOST_UNORDERED_IGNORE_WSTRICT_ALIASING
+#endif
+
+private:
+  opt_storage<T> space;
+};
+
+} /* namespace detail */
+} /* namespace unordered */
+} /* namespace boost */
+
+#endif

include/boost/unordered/detail/bad_archive_exception.hpp

@@ -0,0 +1,27 @@
+/* Copyright 2023 Joaquin M Lopez Munoz.
+ * 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 https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_DETAIL_BAD_ARCHIVE_EXCEPTION_HPP
+#define BOOST_UNORDERED_DETAIL_BAD_ARCHIVE_EXCEPTION_HPP
+
+#include <stdexcept>
+
+namespace boost{
+namespace unordered{
+namespace detail{
+
+struct bad_archive_exception:std::runtime_error
+{
+  bad_archive_exception():std::runtime_error("Invalid or corrupted archive"){}
+};
+
+} /* namespace detail */
+} /* namespace unordered */
+} /* namespace boost */
+
+#endif

include/boost/unordered/detail/concurrent_static_asserts.hpp

@@ -0,0 +1,105 @@
+/* Copyright 2023 Christian Mazakas.
+ * Copyright 2023 Joaquin M Lopez Munoz.
+ * 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 https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_DETAIL_CONCURRENT_STATIC_ASSERTS_HPP
+#define BOOST_UNORDERED_DETAIL_CONCURRENT_STATIC_ASSERTS_HPP
+
+#include <boost/config.hpp>
+#include <boost/mp11/algorithm.hpp>
+#include <boost/mp11/list.hpp>
+
+#include <functional>
+#include <iterator>
+#include <type_traits>
+
+#define BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(F)                             \
+  static_assert(boost::unordered::detail::is_invocable<F, value_type&>::value, \
+    "The provided Callable must be invocable with value_type&");
+
+#define BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(F)                       \
+  static_assert(                                                               \
+    boost::unordered::detail::is_invocable<F, value_type const&>::value,       \
+    "The provided Callable must be invocable with value_type const&");
+
+#if BOOST_CXX_VERSION >= 202002L
+
+#define BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(P)                           \
+  static_assert(!std::is_base_of<std::execution::parallel_unsequenced_policy,  \
+                  ExecPolicy>::value,                                          \
+    "ExecPolicy must be sequenced.");                                          \
+  static_assert(                                                               \
+    !std::is_base_of<std::execution::unsequenced_policy, ExecPolicy>::value,   \
+    "ExecPolicy must be sequenced.");
+
+#else
+
+#define BOOST_UNORDERED_STATIC_ASSERT_EXEC_POLICY(P)                           \
+  static_assert(!std::is_base_of<std::execution::parallel_unsequenced_policy,  \
+                  ExecPolicy>::value,                                          \
+    "ExecPolicy must be sequenced.");
+#endif
+
+#define BOOST_UNORDERED_DETAIL_COMMA ,
+
+#define BOOST_UNORDERED_DETAIL_LAST_ARG(Arg, Args)                             \
+  mp11::mp_back<mp11::mp_list<Arg BOOST_UNORDERED_DETAIL_COMMA Args> >
+
+#define BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_INVOCABLE(Arg, Args)            \
+  BOOST_UNORDERED_STATIC_ASSERT_INVOCABLE(                                     \
+    BOOST_UNORDERED_DETAIL_LAST_ARG(Arg, Args))
+
+#define BOOST_UNORDERED_STATIC_ASSERT_LAST_ARG_CONST_INVOCABLE(Arg, Args)      \
+  BOOST_UNORDERED_STATIC_ASSERT_CONST_INVOCABLE(                               \
+    BOOST_UNORDERED_DETAIL_LAST_ARG(Arg, Args))
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+      template <class F, class... Args>
+      struct is_invocable
+          : std::is_constructible<std::function<void(Args...)>,
+              std::reference_wrapper<typename std::remove_reference<F>::type> >
+      {
+      };
+
+    } // namespace detail
+
+  } // namespace unordered
+
+} // namespace boost
+
+#if defined(BOOST_NO_CXX20_HDR_CONCEPTS)
+#define BOOST_UNORDERED_STATIC_ASSERT_FWD_ITERATOR(Iterator)                   \
+  static_assert(                                                               \
+    std::is_base_of<                                                           \
+      std::forward_iterator_tag,                                               \
+      typename std::iterator_traits<Iterator>::iterator_category>::value,      \
+    "The provided iterator must be at least forward");
+#else
+#define BOOST_UNORDERED_STATIC_ASSERT_FWD_ITERATOR(Iterator)                   \
+  static_assert(std::forward_iterator<Iterator>,                               \
+    "The provided iterator must be at least forward");
+
+#endif
+
+#define BOOST_UNORDERED_STATIC_ASSERT_KEY_COMPATIBLE_ITERATOR(Iterator)        \
+  static_assert(                                                               \
+    std::is_same<                                                              \
+      typename std::iterator_traits<Iterator>::value_type,                     \
+      key_type>::value ||                                                      \
+    detail::are_transparent<                                                   \
+      typename std::iterator_traits<Iterator>::value_type,                     \
+      hasher, key_equal>::value,                                               \
+    "The provided iterator must dereference to a compatible key value");
+
+#define BOOST_UNORDERED_STATIC_ASSERT_BULK_VISIT_ITERATOR(Iterator)            \
+  BOOST_UNORDERED_STATIC_ASSERT_FWD_ITERATOR(Iterator)                         \
+  BOOST_UNORDERED_STATIC_ASSERT_KEY_COMPATIBLE_ITERATOR(Iterator)
+
+#endif // BOOST_UNORDERED_DETAIL_CONCURRENT_STATIC_ASSERTS_HPP