Add an experimental basic_static_cstring template in example/

This introduces a lightweight alternative to basic_static_string
designed for use in POD types: trivially copyable, sizeof == N + 1,
no embedded NULs.

Placed in example/ to gather user feedback before committing to a public
API. See <https://github.com/boostorg/static_string/issues/23>.

.appveyor.yml

@@ -1,5 +1,6 @@
 # Copyright 2016, 2017 Peter Dimov
-# Copyright (C) 2017 - 2019 James E. King III
+# Copyright 2017 - 2019 James E. King III
+# Copyright 2019 - 2021 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
 
@@ -21,7 +22,7 @@
 
 version: 1.0.{build}-{branch}
 
-shallow_clone: true
+shallow_clone: false
 
 branches:
   only:
@@ -33,115 +34,101 @@ branches:
     - /pr\/.*/
 
 matrix:
+  fast_finish: false
   # Adding MAYFAIL to any matrix job allows it to fail but the build stays green:
   allow_failures:
     - MAYFAIL: true
 
 environment:
   global:
+    B2_CI_VERSION: 1
+    GIT_FETCH_JOBS: 4
     # see: http://www.boost.org/build/doc/html/bbv2/overview/invocation.html#bbv2.overview.invocation.properties
     # to use the default for a given environment, comment it out; recommend you build debug and release however:
     # on Windows it is important to exercise all the possibilities, especially shared vs static, however most
     # libraries that care about this exercise it in their Jamfiles...
-    # B2_ADDRESS_MODEL: address-model=64,32
-    # B2_LINK: link=shared,static
+    B2_ADDRESS_MODEL: 32,64
+    B2_LINK: shared,static
     # B2_THREADING: threading=multi,single
-    B2_VARIANT: variant=release
+    B2_VARIANT: release
 
   matrix:
+    - FLAVOR: Visual Studio 2022
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+      B2_CXXFLAGS: -permissive-
+      B2_CXXSTD: 14,17,20
+      B2_TOOLSET: msvc-14.3
+
     - FLAVOR: Visual Studio 2019
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXFLAGS: cxxflags=-permissive-
-      B2_CXXSTD: 17 # 2a
+      B2_CXXFLAGS: -permissive-
+      B2_CXXSTD: 14,17,2a
       B2_TOOLSET: msvc-14.2
 
     - FLAVOR: Visual Studio 2017 C++2a Strict
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXFLAGS: cxxflags=-permissive-
-      B2_CXXSTD: 17 # 2a
+      B2_CXXFLAGS: -permissive-
+      B2_CXXSTD: 2a
       B2_TOOLSET: msvc-14.1
 
-    - FLAVOR: Visual Studio 2017 C++17
+    - FLAVOR: Visual Studio 2017 C++14/17
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXSTD: 17
-      B2_TOOLSET: msvc-14.1
-      B2_VARIANT: variant=debug
-
-    - FLAVOR: Visual Studio 2017 C++14 (Default)
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      B2_ADDRESS_MODEL: address-model=64,32
+      B2_CXXSTD: 14,17
       B2_TOOLSET: msvc-14.1
 
     - FLAVOR: clang-cl
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXSTD: 11
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDCOMMANDS: '"C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"'
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 11,14,17
       B2_TOOLSET: clang-win
 
-    - FLAVOR: Visual Studio 2015 C++14 (Default)
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      B2_ADDRESS_MODEL: address-model=64,32
-      B2_TOOLSET: msvc-14.0
-      B2_VARIANT: variant=debug
+    # not supported
+    # - FLAVOR: Visual Studio 2015, 2013
+    #   APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+    #   B2_TOOLSET: msvc-12.0,msvc-14.0
 
-    - FLAVOR: Visual Studio 2010, 2012, 2013
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      B2_TOOLSET: msvc-10.0,msvc-11.0,msvc-12.0
+    # - FLAVOR: Visual Studio 2008, 2010, 2012
+    #   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: cygwin (32-bit)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       ADDPATH: C:\cygwin\bin;
-      B2_ADDRESS_MODEL: address-model=32
-      B2_CXXSTD: 03,11
-      # https://github.com/boostorg/test/issues/144
-      B2_DEFINES: define=_POSIX_C_SOURCE=200112L
-      B2_THREADING: threadapi=pthread
+      B2_ADDRESS_MODEL: 32
+      B2_CXXSTD: 11,14,1z
       B2_TOOLSET: gcc
-      B2_VARIANT: variant=debug
 
     - FLAVOR: cygwin (64-bit)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       ADDPATH: C:\cygwin64\bin;
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXSTD: 11,17
-      # https://github.com/boostorg/test/issues/144
-      B2_DEFINES: define=_POSIX_C_SOURCE=200112L define=__USE_ISOC99
-      B2_THREADING: threadapi=pthread
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 11,14,1z
       B2_TOOLSET: gcc
 
-    - FLAVOR: mingw32
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      ARCH: i686
-      B2_ADDRESS_MODEL: address-model=32
-      B2_CXXSTD: 03,11
-      SCRIPT: ci\appveyor\mingw.bat
-      B2_VARIANT: variant=debug
+    - FLAVOR: mingw64 (32-bit)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
+      B2_ADDRESS_MODEL: 32
+      B2_CXXSTD: 11,14,17,2a
+      B2_TOOLSET: gcc
 
     - FLAVOR: mingw64
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      ARCH: x86_64
-      B2_ADDRESS_MODEL: address-model=64
-      B2_CXXSTD: 11,17
-      B2_DEFINES: define=__USE_ISOC99
-      SCRIPT: ci\appveyor\mingw.bat
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 11,14,17,2a
+      B2_TOOLSET: gcc
 
 install:
-  - set SELF=%APPVEYOR_PROJECT_NAME:-=_%
-  - git clone https://github.com/boostorg/boost-ci.git C:\boost-ci
-  - xcopy /s /e /q /i C:\boost-ci\ci .\ci
+  - '%ADDCOMMANDS%'
+  - git clone --depth 1 https://github.com/boostorg/boost-ci.git C:\boost-ci-cloned
+  # Copy ci folder if not testing Boost.CI
+  - if NOT "%APPVEYOR_PROJECT_NAME%" == "boost-ci" xcopy /s /e /q /i /y C:\boost-ci-cloned\ci .\ci
+  - rmdir /s /q C:\boost-ci-cloned
   - ci\appveyor\install.bat
 
 build: off
 
-test_script:
-  - set SELF=%APPVEYOR_PROJECT_NAME:-=_%
-  - PATH=%ADDPATH%%PATH%
-  # The definition of B2_TOOLCXX omits B2_CXXSTD= if it was not defined above
-  - IF NOT DEFINED B2_CXXSTD (SET B2_TOOLCXX=toolset=%B2_TOOLSET%) ELSE (SET B2_TOOLCXX=toolset=%B2_TOOLSET% cxxstd=%B2_CXXSTD%)
-  # Echo the complete build command to the build log
-  - IF NOT DEFINED SCRIPT                         (ECHO b2 libs/%SELF:\=/% %B2_TOOLCXX% %B2_CXXFLAGS% %B2_DEFINES% %B2_THREADING% %B2_ADDRESS_MODEL% %B2_LINK% %B2_THREADING% %B2_VARIANT% -j3)
-  # Now go build...
-  - IF DEFINED SCRIPT (call libs\%SELF%\%SCRIPT%) ELSE (b2 libs/%SELF:\=/% %B2_TOOLCXX% %B2_CXXFLAGS% %B2_DEFINES% %B2_THREADING% %B2_ADDRESS_MODEL% %B2_LINK% %B2_THREADING% %B2_VARIANT% -j3)
+test_script: ci\build.bat

.azure-pipelines.yml

@@ -1,276 +0,0 @@
-# Copyright 2015-2019 Rene Rivera.
-# Copyright 2019 Mateusz Loskot <mateusz at loskot dot net>
-# Distributed under the Boost Software License, Version 1.0.
-# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
-
-#
-# Generic Azure Pipelines build script for boostorg repositories
-# See: https://github.com/boostorg/boost-ci/
-#
-# Instructions for customizing this script for your library:
-#
-# 1. Customize the compilers and language levels you want.
-# 2. If you have more than include/, src/, test/, example/, examples/,
-#    benchmark/ or tools/ directories, set the environment variable DEPINST.
-#    For example if your build uses code in "bench/" and "fog/" directories:
-#      - DEPINST: --include bench --include fog
-# 3. Enable pull request builds in your boostorg/<library> account.
-#
-# That's it - the script will do everything else for you.
-
-trigger:
-  branches:
-    include:
-    - develop
-    - master
-    - bugfix/*
-    - feature/*
-    - fix/*
-    - pr/*
-
-pr:
-  branches:
-    include:
-    - develop
-
-variables:
-  - name: B2_VARIANT
-    value: variant=release,debug
-
-stages:
-
-- stage: Test
-  jobs:
-
-  - job: 'Linux'
-    pool:
-      vmImage: 'ubuntu-16.04'
-    strategy:
-      matrix:
-        GCC 8:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 14,17
-          CXX: g++-8
-          PACKAGES: g++-8
-        GCC 7:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 11,14,17
-          CXX: g++-7
-          PACKAGES: g++-7
-        GCC 6:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 11,14
-          CXX: g++-6
-          PACKAGES: g++-6
-        GCC 5:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 11
-          CXX: g++-5
-          PACKAGES: g++-5
-        GCC 4.9:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 11
-          CXX: g++-4.9
-          PACKAGES: g++-4.9
-        GCC 4.8:
-          B2_TOOLSET: gcc
-          B2_CXXSTD: 11
-          CXX: g++-4.8
-          PACKAGES: g++-4.8
-        Clang 8:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17
-          CXX: clang++-8
-          PACKAGES: clang-8
-          LLVM_REPO: llvm-toolchain-xenial-8
-        Clang 7:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17
-          CXX: clang++-7
-          PACKAGES: clang-7
-          LLVM_REPO: llvm-toolchain-xenial-7
-        Clang 6:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17
-          CXX: clang++-6.0
-          PACKAGES: clang-6.0
-          LLVM_REPO: llvm-toolchain-xenial-6.0
-        Clang 5:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17
-          PACKAGES: clang-5.0
-          CXX: clang++-5.0
-          LLVM_REPO: llvm-toolchain-xenial-5.0
-        Clang 4:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17
-          CXX: clang++-4.0
-          PACKAGES: clang-4.0
-          LLVM_REPO: llvm-toolchain-xenial-4.0
-        Clang 3.9:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14
-          CXX: clang++-3.9
-          PACKAGES: clang-3.9
-        Clang 3.8:
-          B2_TOOLSET: clang
-          CXX: clang++-3.8
-          B2_CXXSTD: 11,14
-          PACKAGES: clang-3.8
-        Clang 3.7:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11
-          CXX: clang++-3.7
-          PACKAGES: clang-3.7
-        Clang 3.6:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11
-          CXX: clang++-3.6
-          PACKAGES: clang-3.6
-        Clang 3.5:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11
-          CXX: clang++-3.5
-          PACKAGES: clang-3.5
-    steps:
-    - bash: |
-        set -e
-        uname -a
-        sudo -E apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
-        if test -n "${LLVM_REPO}" ; then
-          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-          sudo -E apt-add-repository "deb http://apt.llvm.org/xenial/ ${LLVM_REPO} main"
-        fi
-        sudo -E apt-get update
-        sudo -E apt-get -yq --no-install-suggests --no-install-recommends install ${PACKAGES}
-
-        git clone --branch master https://github.com/boostorg/boost-ci.git boost-ci
-        cp -pr boost-ci/ci boost-ci/.codecov.yml .
-        rm -rf boost-ci
-        source ci/azure-pipelines/install.sh
-
-        # AzP requires to run special task in order to export
-        # SELF and BOOST_ROOT as job-scoped variable from a script.
-        # NOTE: Disable set -x is necessary, see the troubleshooting guide
-        # on "Variables having ' (single quote) appended":
-        # https://docs.microsoft.com/en-us/azure/devops/pipelines/troubleshooting
-        set +x
-        echo "##vso[task.setvariable variable=SELF]"$SELF
-        echo "##vso[task.setvariable variable=BOOST_ROOT]"$BOOST_ROOT
-        set -x
-      displayName: 'Install'
-    - bash: |
-        set -e
-        echo "SELF=$SELF"
-        echo "BOOST_ROOT=$BOOST_ROOT"
-
-        cd $BOOST_ROOT/libs/$SELF
-        ci/azure-pipelines/build.sh --debug-configuration
-      displayName: 'Build'
-
-  - job: 'Windows'
-    strategy:
-      matrix:
-        VS 2019 C++17 Strict:
-          B2_TOOLSET: msvc-14.2
-          B2_CXXSTD: 17
-          B2_CXXFLAGS: cxxflags=-permissive-
-          B2_ADDRESS_MODEL: address-model=64
-          VM_IMAGE: 'windows-2019'
-        VS 2017 C++17 Strict:
-          B2_TOOLSET: msvc-14.1
-          B2_CXXSTD: 17
-          B2_CXXFLAGS: cxxflags=-permissive-
-          B2_ADDRESS_MODEL: address-model=64
-          VM_IMAGE: 'vs2017-win2016'
-        VS 2017 C++17:
-          B2_TOOLSET: msvc-14.1
-          B2_CXXSTD: 17
-          B2_ADDRESS_MODEL: address-model=64,32
-          VM_IMAGE: 'vs2017-win2016'
-        VS 2017 C++14:
-          B2_TOOLSET: msvc-14.1
-          #B2_CXXSTD: 14 # default
-          B2_ADDRESS_MODEL: address-model=64,32
-          VM_IMAGE: 'vs2017-win2016'
-
-    pool:
-      vmImage: $(VM_IMAGE)
-    steps:
-    - script: |
-        set SELF=%BUILD_REPOSITORY_NAME:-=_%
-        for /f "tokens=2 delims=/" %%a in ("%SELF%") do set SELF=%%a
-        set BOOST_ROOT=%BUILD_SOURCESDIRECTORY%\boost-root
-
-        git clone --branch master https://github.com/boostorg/boost-ci.git boost-ci
-        xcopy /s /e /q /i boost-ci\ci .\ci
-        cmd /k ci\azure-pipelines\install.bat
-
-        echo ##vso[task.setvariable variable=SELF]%SELF%
-        echo ##vso[task.setvariable variable=BOOST_ROOT]%BOOST_ROOT%
-      displayName: 'Install'
-    - script: |
-        PATH=%ADDPATH%%PATH%
-        REM The definition of B2_TOOLCXX omits B2_CXXSTD= if it was not defined above
-        IF NOT DEFINED B2_CXXSTD (SET B2_TOOLCXX=toolset=%B2_TOOLSET%) ELSE (SET B2_TOOLCXX=toolset=%B2_TOOLSET% cxxstd=%B2_CXXSTD%)
-        cd %BOOST_ROOT%
-        ECHO b2 libs/%SELF:\=/% %B2_TOOLCXX% %B2_CXXFLAGS% %B2_DEFINES% %B2_THREADING% %B2_ADDRESS_MODEL% %B2_LINK% %B2_THREADING% %B2_VARIANT% -j3
-        b2 libs/%SELF:\=/% %B2_TOOLCXX% %B2_CXXFLAGS% %B2_DEFINES% %B2_THREADING% %B2_ADDRESS_MODEL% %B2_LINK% %B2_THREADING% %B2_VARIANT% -j3
-      displayName: 'Build'
-
-  - job: 'macOS'
-    pool:
-      vmImage: 'macOS-10.14'
-    strategy:
-      matrix:
-        Xcode_11_3_1:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17,2a
-          XCODE_APP: /Applications/Xcode_11.3.1.app
-        Xcode_11_2_1:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17,2a
-          XCODE_APP: /Applications/Xcode_11.2.1.app
-        Xcode_11_2:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17,2a
-          XCODE_APP: /Applications/Xcode_11.2.app
-        Xcode_11_1:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 14,17,2a
-          XCODE_APP: /Applications/Xcode_11.1.app
-        Xcode_10_3:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17,2a
-          XCODE_APP: /Applications/Xcode_10.3.app
-        Xcode_10_2_1:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17,2a
-          XCODE_APP: /Applications/Xcode_10.2.1.app
-        Xcode_10_2:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17,2a
-          XCODE_APP: /Applications/Xcode_10.2.app
-        Xcode_10_1:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17,2a
-          XCODE_APP: /Applications/Xcode_10.1.app
-        Xcode_10_0:
-          B2_TOOLSET: clang
-          B2_CXXSTD: 11,14,17,2a
-          XCODE_APP: /Applications/Xcode_10.app
-    steps:
-    - bash: |
-        set -e
-        git clone --branch master https://github.com/boostorg/boost-ci.git boost-ci-cloned
-        cp -prf boost-ci-cloned/ci .
-        rm -rf boost-ci-cloned
-        source ci/azure-pipelines/install.sh
-      displayName: Install
-    - bash: |
-        set -e
-        echo "SELF=$SELF"
-        echo "BOOST_ROOT=$BOOST_ROOT"
-        cd $BOOST_ROOT/libs/$SELF
-        ci/azure-pipelines/build.sh
-      displayName: 'Build'

.codecov.yml

@@ -0,0 +1,25 @@
+# Copyright 2019 - 2021 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
+#
+# Sample codecov configuration file. Edit as required
+
+codecov:
+  max_report_age: off
+  require_ci_to_pass: yes
+  notify:
+    # Increase this if you have multiple coverage collection jobs
+    after_n_builds: 1
+    wait_for_ci: yes
+
+# Change how pull request comments look
+comment:
+  layout: "reach,diff,flags,files,footer"
+
+# Ignore specific files or folders. Glob patterns are supported.
+# See https://docs.codecov.com/docs/ignoring-paths
+ignore:
+  - extra/*
+  - extra/**/*
+  - test/*
+  - test/**/*

.drone.star

@@ -0,0 +1,117 @@
+# Use, modification, and distribution are
+# subject to the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE.txt)
+#
+# Copyright (c) 2020 Rene Rivera
+# Copyright (c) 2022 Alan de Freitas
+# Copyright (c) 2022-2025 Alexander Grund
+
+# For Drone CI we use the Starlark scripting language to reduce duplication.
+# As the yaml syntax for Drone CI is rather limited.
+
+# Base environment for all jobs
+globalenv={'B2_VARIANT': 'release'}
+
+# Wrapper function to apply the globalenv to all jobs
+def job(
+        # job specific environment options
+        env={},
+        **kwargs):
+  real_env = dict(globalenv)
+  real_env.update(env)
+  return job_impl(env=real_env, **kwargs)
+
+def main(ctx):
+  return [
+    job(compiler='clang-3.8', cxxstd='11,14',          os='ubuntu-16.04'),
+    job(compiler='clang-3.9', cxxstd='11,14',          os='ubuntu-18.04'),
+    job(compiler='clang-4.0', cxxstd='11,14',          os='ubuntu-18.04'),
+    job(compiler='clang-5.0', cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='clang-6.0', cxxstd='11,14,17',       os='ubuntu-18.04'),
+    job(compiler='clang-7',   cxxstd='11,14,17',       os='ubuntu-18.04'),
+    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-10',  cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-11',  cxxstd='11,14,17,2a',    os='ubuntu-22.04'),
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(compiler='clang-13',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='clang-14',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04', add_llvm=True,
+        env={'B2_CXXFLAGS': '-Werror'}),
+    job(name='Clang 15 standalone', compiler='clang-15',  cxxstd='17,20,2b', os='ubuntu-22.04', add_llvm=True,
+        env={'B2_CXXFLAGS': '-Werror', 'B2_DEFINES': 'BOOST_STATIC_STRING_STANDALONE'}),
+
+    job(compiler='gcc-4.8',   cxxstd='11',             os='ubuntu-16.04'),
+    job(compiler='gcc-4.9',   cxxstd='11',             os='ubuntu-16.04'),
+    job(compiler='gcc-5',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-6',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-7',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-8',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='gcc-9',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='gcc-10',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='gcc-12',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+
+    job(name='Coverage', buildtype='codecov', buildscript='codecov_coveralls', env={'LCOV_BRANCH_COVERAGE': 1, "COVERALLS_REPO_TOKEN": {"from_secret": "coveralls_repo_token"}},
+        compiler='gcc-8',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    # Sanitizers
+    job(name='ASAN',  asan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='UBSAN', ubsan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='TSAN',  tsan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='Clang 14 w/ sanitizers', asan=True, ubsan=True,
+        compiler='clang-14',  cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='Clang 11 libc++ w/ sanitizers', asan=True, ubsan=True, # libc++-11 is the latest working with ASAN: https://github.com/llvm/llvm-project/issues/59432
+        compiler='clang-11',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-11-dev libc++abi-11-dev'),
+    job(name='Valgrind', valgrind=True,
+        compiler='clang-6.0', cxxstd='11,14,1z',       os='ubuntu-18.04', install='libc6-dbg libc++-dev libstdc++-8-dev'),
+
+    # libc++
+    job(compiler='clang-6.0', cxxstd='11,14,17,2a',    os='ubuntu-18.04', stdlib='libc++', install='libc++-dev libc++abi-dev'),
+    job(compiler='clang-7',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-7-dev libc++abi-7-dev'),
+    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-8-dev libc++abi-8-dev'),
+    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-9-dev libc++abi-9-dev'),
+    job(compiler='clang-10',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-10-dev libc++abi-10-dev'),
+    job(compiler='clang-11',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-11-dev libc++abi-11-dev'),
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-12-dev libc++abi-12-dev libunwind-12-dev'),
+    job(compiler='clang-13',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-13-dev libc++abi-13-dev'),
+    job(compiler='clang-14',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-14-dev libc++abi-14-dev'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-15-dev libc++abi-15-dev', add_llvm=True),
+
+    # FreeBSD
+    job(compiler='clang-10',  cxxstd='11,14,17,20',    os='freebsd-13.1'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20',    os='freebsd-13.1'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='freebsd-13.1', linkflags='-Wl,-rpath=/usr/local/lib/gcc11'),
+    # OSX
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-10.1'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-10.3'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-11.1'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-11.7'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-12'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-12.5.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-13.0'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-13.4.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-14.0'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-14.3.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-15.0.1'),
+    # ARM64
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64', add_llvm=True),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64'),
+    # S390x
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x', add_llvm=True),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x'),
+    # Windows
+    job(compiler='msvc-14.0', cxxstd=None,              os='windows', env={'B2_DONT_EMBED_MANIFEST': 1}),
+    job(compiler='msvc-14.1', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.2', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.3', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.0', cxxstd='14,17,20',        os='windows', env={'B2_DONT_EMBED_MANIFEST': 1}),
+    job(compiler='msvc-14.1', cxxstd='14,17,20',        os='windows'),
+    job(compiler='msvc-14.2', cxxstd='14,17,20',        os='windows'),
+    job(compiler='msvc-14.3', cxxstd='14,17,20,latest', os='windows'),
+  ]
+
+# from https://github.com/boostorg/boost-ci
+load("@boost_ci//ci/drone/:functions.star", "linux_cxx", "windows_cxx", "osx_cxx", "freebsd_cxx", "job_impl")

.drone/codecov_coveralls.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Copyright 2020 Rene Rivera, Sam Darwin
+# Copyright 2025 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE.txt or copy at http://boost.org/LICENSE_1_0.txt)
+
+
+set -xe
+
+# Run the regular Boost CI script which does the test & upload to codecov.io
+wget https://github.com/boostorg/boost-ci/raw/refs/heads/master/.drone/drone.sh
+. drone.sh
+
+# coveralls
+# uses multiple lcov steps from boost-ci codecov.sh script
+if [ -n "${COVERALLS_REPO_TOKEN}" ]; then
+    echo "processing coveralls"
+    pip3 install --user cpp-coveralls
+    cd "$BOOST_CI_SRC_FOLDER"
+
+    export PATH=/tmp/lcov/bin:$PATH
+    command -v lcov
+    lcov --version
+
+    lcov --remove coverage.info -o coverage_filtered.info '*/test/*' '*/extra/*'
+    cpp-coveralls --verbose -l coverage_filtered.info
+fi

.github/workflows/ci.yml

@@ -0,0 +1,50 @@
+#
+# Copyright 2020-2021 Peter Dimov
+# Copyright 2021 Andrey Semashev
+# Copyright 2021-2025 Alexander Grund
+# Copyright 2022-2025 James E. King III
+#
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
+#
+# This workflow uses the Boost.CI reusable workflow which builds a variety of
+# configurations of your project, runs tests, and generates code coverage reports.
+#
+# To use it, copy this file into your repository as `.github/workflows/ci.yml` and
+# customize it appropriately.
+# 
+---
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - develop
+      - bugfix/**
+      - feature/**
+      - fix/**
+      - github/**
+      - pr/**
+    paths-ignore:
+      - LICENSE
+      - meta/**
+      - README.md
+
+jobs:
+  call-boost-ci:
+    name: Run Boost.CI
+    uses: boostorg/boost-ci/.github/workflows/reusable.yml@master
+    with:
+      exclude_cxxstd: '98,03,0x'
+      enable_pr_coverage: false
+      enable_multiarch: false
+    # Example of customization:
+    # with:
+    #   enable_reflection: true
+    #   enable_windows: false
+    # secrets:
+    #   CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+    #   COVERITY_SCAN_NOTIFICATION_EMAIL: ${{ secrets.COVERITY_SCAN_NOTIFICATION_EMAIL }}
+    #   COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}

.github/workflows/example.yml

@@ -0,0 +1,38 @@
+#
+# Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/static_string
+#
+
+name: Example (basic_static_cstring)
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - develop
+      - bugfix/**
+      - feature/**
+      - fix/**
+      - github/**
+      - pr/**
+    paths-ignore:
+      - LICENSE
+      - meta/**
+      - README.md
+
+env:
+  B2_TARGETS: libs/$SELF/example
+
+jobs:
+  call-boost-ci:
+    name: Run Boost.CI
+    uses: boostorg/boost-ci/.github/workflows/reusable.yml@master
+    with:
+      exclude_cxxstd: '98,03,0x,11,14,17'
+      enable_pr_coverage: false
+      enable_multiarch: false

.gitignore

@@ -1,8 +1,15 @@
 bin/
 bin64/
+build/
 
 # Because of CMake and VS2017
 Win32/
 x64/
 .vs/
-out/
+out/
+
+# VS CMake settings
+/CMakeSettings.json
+# CMake presets
+/CMakePresets.json
+/CMakeUserPresets.json

.travis.yml

@@ -1,275 +0,0 @@
-# Copyright 2016 Peter Dimov
-# Copyright 2017 - 2019 James E. King III
-# Copyright 2020 Krystian Stasiowski
-# Distributed under the Boost Software License, Version 1.0.
-# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
-
-#
-# Generic Travis CI build script for boostorg repositories
-# See: https://github.com/boostorg/boost-ci
-#
-# Instructions for customizing this script for your library:
-#
-# 1. Customize the compilers and language levels you want in the 'jobs'.
-# 2. If you have more than include/, src/, test/, example/, examples/, or
-#    tools/ directories, modify your Travis CI project and add the environment
-#    variable DEPINST.  For example if your build uses code in "bench/" and
-#    "fog/" directories, then set DEPINST to the following:
-#        --include bench --include fog
-# 3. If you want to enable Coverity Scan, you need to provide the environment
-#    variables COVERITY_SCAN_TOKEN and COVERITY_SCAN_NOTIFICATION_EMAIL in
-#    your github settings.
-# 4. If you want to enable a big-endian build, you need to uncomment the
-#    big-endian build job.
-# 5. Enable pull request builds in your boostorg/<library> account.
-#
-# That's it - the scripts will do everything else for you.
-
-dist: xenial
-language: cpp
-
-env:
-  global:
-  # see: http://www.boost.org/build/doc/html/bbv2/overview/invocation.html#bbv2.overview.invocation.properties
-  # - B2_ADDRESS_MODEL=address-model=64,32
-  # - B2_LINK=link=shared,static
-  # - B2_THREADING=threading=multi,single
-    - B2_VARIANT=variant=release
-
-install:
-  - git clone https://github.com/boostorg/boost-ci.git boost-ci
-  - cp -pr boost-ci/ci boost-ci/.codecov.yml .
-  - source ci/travis/install.sh
-
-addons:
-  apt:
-    packages:
-      - binutils-gold
-      - gdb
-      - libc6-dbg
-      - qemu-user-static
-
-services:
-  - docker
-
-branches:
-  only:
-    - master
-    - develop
-    - /bugfix\/.*/
-    - /feature\/.*/
-    - /fix\/.*/
-    - /pr\/.*/
-
-script:
-  - cd $BOOST_ROOT/libs/$SELF
-  - ci/travis/build.sh
-
-#
-# Default toolsets in Ubuntu
-#
-#       trusty xenial bionic
-#        14.04  16.04  18.04
-#       ------ ------ ------
-# clang    3.4    3.8    6.0
-#   gcc  4.8.2  5.3.1  7.3.0
-#
-
-anchors:
-  clang-38: &clang-38 { apt: { packages: [ "clang-3.8",
-                                           "libstdc++-6-dev" ], sources: [ "llvm-toolchain-xenial-3.8",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-  clang-4:  &clang-4  { apt: { packages: [ "clang-4.0",
-                                           "libstdc++-6-dev" ], sources: [ "llvm-toolchain-xenial-4.0",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-  clang-5:  &clang-5  { apt: { packages: [ "clang-5.0",
-                                           "libstdc++-7-dev" ], sources: [ "llvm-toolchain-xenial-5.0",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-  clang-6:  &clang-6  { apt: { packages: [ "clang-6.0",
-                                           "libc6-dbg",
-                                           "libc++-dev",
-                                           "libstdc++-8-dev" ], sources: [ "llvm-toolchain-xenial-6.0",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-  clang-7:  &clang-7  { apt: { packages: [ "clang-7",
-                                           "libc6-dbg",
-                                           "libc++-dev",
-                                           "libstdc++-8-dev" ], sources: [ "llvm-toolchain-xenial-7",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-  clang-8:  &clang-8  { apt: { packages: [ "clang-8",
-                                           "libc6-dbg",
-                                           "libc++-dev",
-                                           "libstdc++-8-dev" ], sources: [ "llvm-toolchain-xenial-8",
-                                                                           "ubuntu-toolchain-r-test"   ] } }
-
-  gcc-48:   &gcc-48   { apt: { packages: [ "g++-4.8"         ]                                           } }
-  gcc-49:   &gcc-49   { apt: { packages: [ "g++-4.9"         ], sources: [ "ubuntu-toolchain-r-test"   ] } }
-  gcc-5:    &gcc-5    { apt: { packages: [ "g++-5"           ]                                           } }
-  gcc-6:    &gcc-6    { apt: { packages: [ "g++-6"           ], sources: [ "ubuntu-toolchain-r-test"   ] } }
-  gcc-7:    &gcc-7    { apt: { packages: [ "g++-7"           ], sources: [ "ubuntu-toolchain-r-test"   ] } }
-  gcc-8:    &gcc-8    { apt: { packages: [ "g++-8"           ], sources: [ "ubuntu-toolchain-r-test"   ] } }
-  gcc-9:    &gcc-9    { apt: { packages: [ "g++-9"           ], sources: [ "ubuntu-toolchain-r-test"   ] } }
-
-jobs:
-  allow_failures:
-    - env:
-      - COPY="all the environment settings from your job"
-
-  include:
-    # coverage
-    - os: linux
-      env:
-        - COMMENT=codecov.io
-        - B2_CXXSTD=11
-        - B2_TOOLSET=gcc-8
-        - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-      addons: *gcc-8
-      script:
-        - cd $BOOST_ROOT/libs/$SELF
-        - tools/codecov.sh
-
-    - os: linux
-      env:
-        - COMMENT=asan
-        - B2_VARIANT=variant=debug
-        - B2_TOOLSET=gcc-8
-        - B2_CXXSTD=11,14
-        - B2_CXXFLAGS="address-sanitizer=norecover"
-        - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-      addons: *gcc-8
-
-    - os: linux
-      env:
-        - COMMENT=tsan
-        - B2_VARIANT=variant=debug
-        - B2_TOOLSET=gcc-8
-        - B2_CXXSTD=11,14
-        - B2_CXXFLAGS="thread-sanitizer=norecover"
-        - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-      addons: *gcc-8
-
-    - os: linux
-      env:
-        - COMMENT=ubsan
-        - B2_VARIANT=variant=debug
-        - B2_TOOLSET=gcc-8
-        - B2_CXXSTD=11,14
-        - B2_CXXFLAGS="undefined-sanitizer=norecover"
-        - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-        - B2_LINKFLAGS="linkflags=-fuse-ld=gold"
-        - UBSAN_OPTIONS=print_stacktrace=1
-      addons: *gcc-8
-
-    - os: linux
-      env:
-        - COMMENT=valgrind
-        - B2_TOOLSET=clang-6.0
-        - B2_CXXSTD=11,14
-        - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-        - B2_VARIANT=variant=debug
-        - B2_TESTFLAGS=testing.launcher=valgrind
-        - VALGRIND_OPTS=--error-exitcode=1
-      addons: *clang-6
-      script:
-        - cd $BOOST_ROOT/libs/$SELF
-        - ci/travis/valgrind.sh
-
-    # libstdc++
-    - { os: "linux", dist: "trusty",  # xenial has libstdc++ from gcc 5.4.0 with newer ABI
-                     env: [ "B2_TOOLSET=gcc-4.8",     "B2_CXXSTD=11"      ], addons: *gcc-48    }
-    - { os: "linux", dist: "trusty",  # xenial has libstdc++ from gcc 5.4.0 with newer ABI
-                     env: [ "B2_TOOLSET=gcc-4.9",     "B2_CXXSTD=11"       ], addons: *gcc-49    }
-    - { os: "linux", env: [ "B2_TOOLSET=gcc-5",       "B2_CXXSTD=11,14"       ], addons: *gcc-5     }
-    - { os: "linux", env: [ "B2_TOOLSET=gcc-6",       "B2_CXXSTD=11,14"    ], addons: *gcc-6     }
-    - { os: "linux", env: [ "B2_TOOLSET=gcc-7",       "B2_CXXSTD=14,17"    ], addons: *gcc-7     }
-    - { os: "linux", env: [ "B2_TOOLSET=gcc-8",       "B2_CXXSTD=17"    ], addons: *gcc-8     }
-    - { os: "linux", env: [ "B2_TOOLSET=gcc-9",       "B2_CXXSTD=17"    ], addons: *gcc-9     }
-    - { os: "linux", dist: "trusty",  # xenial has libstdc++ from gcc 5.4.0 with newer ABI
-                     env: [ "B2_TOOLSET=clang-3.8",   "B2_CXXSTD=11"       ], addons: *clang-38  }
-    - { os: "linux", env: [ "B2_TOOLSET=clang-4.0",   "B2_CXXSTD=11,14"    ], addons: *clang-4   }
-    - { os: "linux", env: [ "B2_TOOLSET=clang-5.0",   "B2_CXXSTD=11,14"    ], addons: *clang-5   }
-    - { os: "linux", env: [ "B2_TOOLSET=clang-6.0",   "B2_CXXSTD=14,17"    ], addons: *clang-6   }
-    - { os: "linux", env: [ "B2_TOOLSET=clang-7",     "B2_CXXSTD=17"    ], addons: *clang-7   }
-    - { os: "linux", env: [ "B2_TOOLSET=clang-8",     "B2_CXXSTD=17"    ], addons: *clang-8   }
-
-    -   os: "linux"
-        env: ["B2_TOOLSET=clang-9", "B2_CXXSTD=11,14,17"]
-        addons:
-          apt:
-            sources:
-              - ubuntu-toolchain-r-test
-              - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-9 main'
-                key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
-            packages:
-              - clang-9
-              - libc6-dbg
-              - libc++-dev
-              - libstdc++-8-dev
-
-    # libc++
-    - { os: "linux", env: [ "B2_TOOLSET=clang-6.0",   "B2_CXXSTD=11,14",
-                            "B2_CXXFLAGS=-stdlib=libc++"                   ], addons: *clang-6   }
-    - { os: "osx"  , env: [ "B2_TOOLSET=clang",       "B2_CXXSTD=11,17"    ]                     }
-
-    # to enable Intel ICC define INTEL_ICC_SERIAL_NUMBER and the following (under development):
-    # - { os: "linux", env: [ "B2_TOOLSET=intel-linux", "B2_CXXSTD=11,14,17" ], addons: *gcc-7,
-    #     script: cd $BOOST_ROOT/libs/$SELF && ci/travis/intelicc.sh                               }
-
-    # uncomment to enable a big-endian build job, just note that it is 5-10 times slower
-    # than a regular build and travis has a 50 minute time limit per job
-    # - os: linux
-    #   env:
-    #     - COMMENT=big-endian
-    #     - B2_CXXSTD=03
-    #     - B2_TOOLSET=gcc
-    #     - B2_DEFINES="define=BOOST_NO_STRESS_TEST=1"
-    #     - BDDE_OS=red
-    #     - BDDE_ARCH=ppc64
-    #   script:
-    #     - cd $BOOST_ROOT/libs/$SELF
-    #     - ci/travis/bdde.sh
-
-    # - os: linux
-    #   env:
-    #     - COMMENT=cppcheck
-    #   script:
-    #     - cd $BOOST_ROOT/libs/$SELF
-    #     - ci/travis/cppcheck.sh
-
-    #################### Jobs to run on pushes to master, develop ###################
-
-    # Coverity Scan
-    - os: linux
-      if: (env(COVERITY_SCAN_NOTIFICATION_EMAIL) IS present) AND (branch IN (develop, master)) AND (type IN (cron, push))
-      env:
-        - COMMENT="Coverity Scan"
-        - B2_TOOLSET=clang
-      script:
-        - cd $BOOST_ROOT/libs/$SELF
-        - ci/travis/coverity.sh
-
-    # Standalone tests for StaticString
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=gcc-7",       "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *gcc-7     }
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=gcc-8",       "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *gcc-8     }
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=gcc-9",       "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *gcc-9     }
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=clang-6.0",   "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *clang-6   }
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=clang-7",     "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *clang-7   }
-    - { os: "linux", env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=clang-8",     "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"                                        ], addons: *clang-8   }
-    -   os: "linux"
-        env: ["COMMENT=STANDALONE", "B2_TOOLSET=clang-9", "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE", "B2_CXXSTD=17"]
-        addons:
-          apt:
-            sources:
-              - ubuntu-toolchain-r-test
-              - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-9 main'
-                key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
-            packages:
-              - clang-9
-              - libc6-dbg
-              - libc++-dev
-              - libstdc++-8-dev
-
-    - { os: "osx"  , env: [ "COMMENT=STANDALONE",       "B2_TOOLSET=clang",       "B2_DEFINES=define=BOOST_STATIC_STRING_STANDALONE",       "B2_CXXSTD=17"     ]                     }
-
-notifications:
-  email:
-    false

CMakeLists.txt

@@ -1,32 +1,5 @@
-# Generated by `boostdep --cmake static_string`
-# Copyright 2020 Peter Dimov
-# Distributed under the Boost Software License, Version 1.0.
-# https://www.boost.org/LICENSE_1_0.txt
-
-cmake_minimum_required(VERSION 3.5...3.16)
-
-project(boost_static_string VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
-
-if(NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-
-add_library(boost_static_string INTERFACE)
-add_library(Boost::static_string ALIAS boost_static_string)
-
-target_include_directories(boost_static_string INTERFACE include)
-
-target_link_libraries(boost_static_string
-  INTERFACE
-    Boost::assert
-    Boost::container_hash
-    Boost::static_assert
-    Boost::throw_exception
-    Boost::utility
-)
-
-else()
-
 #
-# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+# Copyright (c) 2022 Alan de Freitas (alandefreitas@gmail.com)
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -34,140 +7,111 @@ else()
 # Official repository: https://github.com/boostorg/static_string
 #
 
-#-------------------------------------------------------------------------------
+cmake_minimum_required(VERSION 3.8...3.16)
 
-function (DoGroupSources curdir rootdir folder)
-    file (GLOB children RELATIVE ${PROJECT_SOURCE_DIR}/${curdir} ${PROJECT_SOURCE_DIR}/${curdir}/*)
-    foreach (child ${children})
-        if (IS_DIRECTORY ${PROJECT_SOURCE_DIR}/${curdir}/${child})
-            DoGroupSources (${curdir}/${child} ${rootdir} ${folder})
-        elseif (${child} STREQUAL "CMakeLists.txt")
-            source_group("" FILES ${PROJECT_SOURCE_DIR}/${curdir}/${child})
-        else()
-            string (REGEX REPLACE ^${rootdir} ${folder} groupname ${curdir})
-            string (REPLACE "/" "\\" groupname ${groupname})
-            source_group (${groupname} FILES ${PROJECT_SOURCE_DIR}/${curdir}/${child})
-        endif()
-    endforeach()
-endfunction()
+project(boost_static_string VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
-function (GroupSources curdir folder)
-    DoGroupSources (${curdir} ${curdir} ${folder})
-endfunction()
+set(BOOST_STATIC_STRING_IS_ROOT OFF)
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    set(BOOST_STATIC_STRING_IS_ROOT ON)
+endif ()
 
-#-------------------------------------------------------------------------------
-#
-# StaticString
-#
-#-------------------------------------------------------------------------------
+if (BOOST_STATIC_STRING_IS_ROOT)
+    include(CTest)
+endif ()
 
-set_property (GLOBAL PROPERTY USE_FOLDERS ON)
+# Options
+if (NOT BOOST_SUPERPROJECT_VERSION)
+    option(BOOST_STATIC_STRING_INSTALL "Install boost::static_string files" ${BOOST_STATIC_STRING_IS_ROOT})
+    option(BOOST_STATIC_STRING_BUILD_TESTS "Build boost::static_string tests" OFF)
+else ()
+    set(BOOST_STATIC_STRING_BUILD_TESTS ${BUILD_TESTING})
+endif ()
 
-if (MSVC)
-    set (CMAKE_VERBOSE_MAKEFILE FALSE)
+# Find boost
+if (BOOST_SUPERPROJECT_VERSION)
+    set(BOOST_STATIC_STRING_FIND_PACKAGE_BOOST OFF)
+elseif (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../CMakeLists.txt" AND
+        EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../Jamroot" AND
+        EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../boost-build.jam" AND
+        EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../bootstrap.sh" AND
+        EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../libs")
+    set(BOOST_STATIC_STRING_FIND_PACKAGE_BOOST OFF)
+else ()
+    set(BOOST_STATIC_STRING_FIND_PACKAGE_BOOST ON)
+endif ()
 
-    add_definitions (
-        -D_WIN32_WINNT=0x0601
-    )
+if (BOOST_STATIC_STRING_FIND_PACKAGE_BOOST)
+    find_package(Boost 1.78.0 REQUIRED COMPONENTS container)
+elseif (BOOST_STATIC_STRING_IS_ROOT)
+    set(BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES core)
+    set(BOOST_INCLUDE_LIBRARIES static_string assert container_hash throw_exception utility ${BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES})
+    set(BOOST_EXCLUDE_LIBRARIES static_string)
+    set(CMAKE_FOLDER Dependencies)
+    add_subdirectory(../.. Dependencies/boost EXCLUDE_FROM_ALL)
+    unset(CMAKE_FOLDER)
+endif ()
 
-    add_compile_options(
-        /permissive-  # strict C++
-        /W4           # enable all warnings
-        /MP           # Multi-processor compilation
+# Sources
+include(GNUInstallDirs)
+file(GLOB_RECURSE BOOST_STATIC_STRING_HEADERS CONFIGURE_DEPENDS
+        include/boost/*.hpp
+        include/boost/*.ipp
+        include/boost/*.natvis
         )
 
-    set (Boost_USE_STATIC_LIBS ON)
-    set (Boost_USE_STATIC_RUNTIME ON)
+set_property(GLOBAL PROPERTY USE_FOLDERS ON)
+source_group(TREE ${CMAKE_CURRENT_SOURCE_DIR}/include/boost PREFIX "" FILES ${BOOST_STATIC_STRING_HEADERS})
+source_group(TREE ${CMAKE_CURRENT_SOURCE_DIR}/src PREFIX "" FILES ${BOOST_STATIC_STRING_SOURCES})
 
-    set (CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MTd")
-    set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Ob2 /Oi /Ot /GL /MT")
-    set (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /Oi /Ot /MT")
+# Target
+add_library(boost_static_string INTERFACE)
+add_library(Boost::static_string ALIAS boost_static_string)
 
-    set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /SAFESEH:NO")
-    set (CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /LTCG")
+target_compile_features(boost_static_string INTERFACE cxx_constexpr)
+if (BOOST_SUPERPROJECT_VERSION)
+    target_include_directories(boost_static_string INTERFACE "${PROJECT_SOURCE_DIR}/include")
+else ()
+    target_include_directories(boost_static_string
+            INTERFACE
+            "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>"
+            "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
+            )
+endif ()
 
-    # for RelWithDebInfo builds, disable incremental linking
-    # since CMake sets it ON by default for that build type and it
-    # causes warnings
-    #
-    string (REPLACE "/INCREMENTAL" "/INCREMENTAL:NO" replacement_flags
-        ${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO})
-    set (CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO ${replacement_flags})
+if (BOOST_STATIC_STRING_FIND_PACKAGE_BOOST)
+    target_link_libraries(boost_static_string
+            INTERFACE
+            Boost::headers
+            )
+else ()
+    target_link_libraries(boost_static_string
+            INTERFACE
+            Boost::assert
+            Boost::container_hash
+            Boost::core
+            Boost::throw_exception
+            Boost::utility
+            )
+endif ()
 
-else()
-    set (THREADS_PREFER_PTHREAD_FLAG ON)
-    find_package (Threads)
+if (BOOST_STATIC_STRING_INSTALL AND NOT BOOST_SUPERPROJECT_VERSION)
+    install(TARGETS boost_static_string
+            RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+            LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+            ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+            )
 
-    set( CMAKE_CXX_FLAGS
-      "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wextra -Wpedantic -Wno-unused-parameter")
+    install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/include/boost
+            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+            FILES_MATCHING
+            PATTERN "*.hpp"
+            PATTERN "*.ipp"
+            )
+endif ()
 
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wrange-loop-analysis")
-    endif ()
-endif()
 
-# Must come before Boost includes, otherwise the
-# IDE sees the wrong file due to boost/ symlinks.
-include_directories (include)
+if (BUILD_TESTING OR BOOST_STATIC_STRING_BUILD_TESTS)
+    add_subdirectory(test)
+endif ()
 
-#-------------------------------------------------------------------------------
-#
-# Boost
-#
-#-------------------------------------------------------------------------------
-
-get_filename_component (BOOST_ROOT ../../ ABSOLUTE)
-
-# VFALCO I want static but "b2 stage" builds a minimal set which excludes static
-add_definitions (-DBOOST_ALL_STATIC_LINK=1)
-
-include_directories (${BOOST_ROOT})
-
-link_directories(${BOOST_ROOT}/stage/lib)
-
-#-------------------------------------------------------------------------------
-
-if ("${VARIANT}" STREQUAL "coverage")
-    if (MSVC)
-    else()
-        set (CMAKE_BUILD_TYPE DEBUG)
-        set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.2 --coverage")
-        set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --coverage")
-    endif()
-
-elseif ("${VARIANT}" STREQUAL "ubasan")
-    if (MSVC)
-    else()
-        set (CMAKE_BUILD_TYPE RELWITHDEBINFO)
-        set (CMAKE_CXX_FLAGS
-          "${CMAKE_CXX_FLAGS} -msse4.2 -funsigned-char -fno-omit-frame-pointer -fsanitize=address,undefined -fno-sanitize-recover=address,undefined -fsanitize-blacklist=${PROJECT_SOURCE_DIR}/tools/blacklist.supp")
-        set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fsanitize=address,undefined -fno-sanitize-recover=address,undefined")
-    endif()
-
-elseif ("${VARIANT}" STREQUAL "debug")
-    set (CMAKE_BUILD_TYPE DEBUG)
-
-elseif ("${VARIANT}" STREQUAL "release")
-    set (CMAKE_BUILD_TYPE RELEASE)
-
-endif()
-
-#-------------------------------------------------------------------------------
-
-#GroupSources (test "/")
-
-#-------------------------------------------------------------------------------
-#
-# Tests and examples
-#
-
-#include_directories (.)
-
-file (GLOB_RECURSE PROJECT_FILES
-    ${PROJECT_SOURCE_DIR}/include/boost/static_string/*.hpp
-    ${PROJECT_SOURCE_DIR}/include/boost/static_string/*.ipp
-)
-
-add_subdirectory (test)
-
-endif()

Jamfile

@@ -1,10 +0,0 @@
-#
-# Copyright (c) 2019 Vinnie Falco (vinnie dot falco at gmail dot com)
-#
-# Distributed under the Boost Software License, Version 1.0. (See accompanying
-# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-#
-# Official repository: https://github.com/boostorg/static_string
-#
-
-build-project test ;

README.md

@@ -1,9 +1,9 @@
 # Boost.StaticString
 
-Branch          | Travis | Appveyor | Azure Pipelines | codecov.io | Docs | Matrix |
+Branch          | GHA CI | Appveyor | Azure Pipelines | codecov.io | Docs | Matrix |
 :-------------: | ------ | -------- | --------------- | ---------- | ---- | ------ |
-[`master`](https://github.com/boostorg/static_string/tree/master) | [![Build Status](https://travis-ci.org/boostorg/static_string.svg?branch=master)](https://travis-ci.org/boostorg/static_string) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/master?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/master) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=master)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=master) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/master) | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](http://www.boost.org/doc/libs/release/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](http://www.boost.org/development/tests/master/developer/static_string.html)
-[`develop`](https://github.com/boostorg/static_string/tree/develop) | [![Build Status](https://travis-ci.org/boostorg/static_string.svg?branch=develop)](https://travis-ci.org/boostorg/static_string) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/develop?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/develop) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=develop)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=develop) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/develop) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](http://www.boost.org/doc/libs/develop/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](http://www.boost.org/development/tests/develop/developer/static_string.html)
+[`master`](https://github.com/boostorg/static_string/tree/master) | [![Build Status](https://github.com/boostorg/static_string/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/static_string/actions?query=branch:master) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/master?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/master) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=master)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=master) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/master) | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](http://www.boost.org/doc/libs/release/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](https://regression.boost.org/master/developer/static_string.html)
+[`develop`](https://github.com/boostorg/static_string/tree/develop) | [![Build Status](https://github.com/boostorg/static_string/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/static_string/actions?query=branch:develop) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/develop?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/develop) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=develop)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=develop) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/develop) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](http://www.boost.org/doc/libs/develop/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](https://regression.boost.org/develop/developer/static_string.html)
 
 ## Introduction
 

build.jam

@@ -0,0 +1,27 @@
+# Copyright René Ferdinand Rivera Morell 2023-2024
+# 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)
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/assert//boost_assert
+    /boost/config//boost_config
+    /boost/container_hash//boost_container_hash
+    /boost/core//boost_core
+    /boost/throw_exception//boost_throw_exception
+    /boost/utility//boost_utility ;
+
+project /boost/static_string
+    ;
+
+explicit
+    [ alias boost_static_string : : :
+        : <include>include <library>$(boost_dependencies) ]
+    [ alias all : boost_static_string test ]
+    ;
+
+call-if : boost-library static_string
+    ;
+

doc/Jamfile

@@ -1,6 +1,7 @@
 #
 # Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
 # Copyright (c) 2020 Krystian Stasiowski (sdkrystian at gmail dot com)
+# Copyright (c) 2022 Alan de Freitas (alandefreitas@gmail.com)
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -8,20 +9,21 @@
 
 project static_string/doc ;
 
-import boostbook ;
-import ../../../tools/docca/docca.jam ;
+import-search /boost/docca ;
 
+import docca ;
+import path ;
+import os ;
 
-docca.reference reference.qbk
+local include-prefix = [ path.root $(__file__:D) [ path.pwd ] ] ;
+include-prefix = [ path.native $(include-prefix:D)/include ] ;
+
+docca.pyreference reference.qbk
     :
-        xsl/custom-overrides.xsl
         [ glob-tree-ex ../include/boost/static_string : *.hpp *.ipp : detail impl ]
+        externals.hpp
     :
-        <doxygen:param>PROJECT_NAME=StaticString
-        <doxygen:param>PROJECT_BRIEF="String Library"
         <doxygen:param>ALIASES="esafe=\"@par Exception Safety\""
-        <doxygen:param>FILE_PATTERNS=
-        <doxygen:param>EXAMPLE_PATTERNS=
         <doxygen:param>DISTRIBUTE_GROUP_DOC=YES
         <doxygen:param>MACRO_EXPANSION=YES
         <doxygen:param>EXPAND_ONLY_PREDEF=YES
@@ -38,19 +40,17 @@ docca.reference reference.qbk
         <doxygen:param>EXTRACT_ALL=YES
         <doxygen:param>EXTRACT_PRIVATE=YES
         <doxygen:param>EXTRACT_LOCAL_CLASSES=NO
-        <doxygen:param>SHOW_INCLUDE_FILES=NO
         <doxygen:param>INLINE_INFO=NO
         <doxygen:param>SORT_MEMBER_DOCS=NO
         <doxygen:param>SORT_MEMBERS_CTORS_1ST=YES
-        <doxygen:param>SHOW_USED_FILES=NO
-        <doxygen:param>SHOW_FILES=NO
-        <doxygen:param>SHOW_NAMESPACES=NO
-        <doxygen:param>CLASS_DIAGRAMS=NO
+        <doxygen:param>STRIP_FROM_PATH=$(include-prefix)
 
         # <doxygen:param>ALLOW_UNICODE_NAMES=NO
         # <doxygen:param>GROUP_NESTED_COMPOUNDS=NO
         # <doxygen:param>HIDE_COMPOUND_REFERENCE=NO
         # <doxygen:param>WARN_AS_ERROR=NO
+
+        <docca:config>config.json
     ;
 
 #-------------------------------------------------------------------------------
@@ -90,7 +90,7 @@ boostbook static_string
         <xsl:param>chapter.autolabel=0
         <xsl:param>chunk.section.depth=8               # Depth to which sections should be chunked
         <xsl:param>chunk.first.sections=1              # Chunk the first top-level section?
-        <xsl:param>generate.toc=""
+        <xsl:param>generate.toc="chapter toc,title section nop reference nop"
         <include>../../../tools/boostbook/dtd
     :
         <dependency>images

doc/config.json

@@ -0,0 +1,12 @@
+{
+    "include_private": false,
+    "legacy_behavior": false,
+    "external_marker": "!EXTERNAL!",
+    "link_prefix": "static_string.ref.",
+    "default_namespace": "boost::static_strings",
+    "allowed_prefixes": ["boost::static_strings::", "std::"],
+    "convenience_header": "boost/static_string.hpp",
+    "replace_strings": {
+        "__see_below__": "``['see-below]``"
+    }
+}

doc/externals.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+namespace boost {
+
+/// !EXTERNAL!
+///
+/// @see https://www.boost.org/doc/libs/release/libs/utility/doc/html/utility/utilities/string_view.html
+template <class T, class Traits>
+struct basic_string_view {};
+
+} // namespace boost
+
+namespace std {
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/iterator/reverse_iterator
+template <class T>
+struct reverse_iterator {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/size_t
+struct size_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/integer
+struct uint64_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/integer
+struct int64_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/nullptr_t
+struct nullptr_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/ptrdiff_t
+struct ptrdiff_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/utility/initializer_list
+template <class T>
+struct initializer_list {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/io/basic_ostream
+template <class T, class Traits>
+struct basic_ostream {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/numeric_limits
+template <class T>
+struct numeric_limits {};
+
+} // namespace std

doc/xsl/custom-overrides.xsl

@@ -1,11 +0,0 @@
-<xsl:stylesheet version="3.0"
-  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
-  xmlns:xs="http://www.w3.org/2001/XMLSchema"
-  exclude-result-prefixes="xs"
-  expand-text="yes">
-
-  <xsl:variable name="doc-ref" select="'static_string.ref'"/>
-  <xsl:variable name="doc-ns" select="'boost::static_strings'"/>
-  <xsl:variable name="include-private-members" select="false()"/>
-
-</xsl:stylesheet>

example/static_cstring/Jamfile

@@ -0,0 +1,19 @@
+#
+# Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/static_string
+#
+
+import testing ;
+
+project
+  : requirements
+    <include>../../include
+    <warnings>extra
+    <cxxstd>20
+  ;
+
+run static_cstring_test.cpp ;

example/static_cstring/README.md

@@ -0,0 +1,13 @@
+This directory contains an experimental implementation of `basic_static_cstring`, which differs from `basic_static_string` in the following ways:
+
+|                     | `basic_static_cstring` | `basic_static_string` |
+|---------------------|------------------------|-----------------------|
+| Layout              | `sizeof == N + 1`      | Has size member       |
+| Embedded NULs       | Not supported          | Supported             |
+| Trivially copyable  | Yes                    | No                    |
+
+Additionally, when `N <= UCHAR_MAX`, `basic_static_cstring` employs an optimization that avoids calling `std::strlen()` to compute the size.
+
+This work stems from [boostorg/static_string#23](https://github.com/boostorg/static_string/issues/23).
+
+If you believe `basic_static_cstring` should become part of the public API, please share your feedback on the Boost mailing list.

example/static_cstring/static_cstring.hpp

@@ -0,0 +1,449 @@
+//
+// Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#ifndef BOOST_STATIC_STRING_STATIC_CSTRING_HPP
+#define BOOST_STATIC_STRING_STATIC_CSTRING_HPP
+
+#include <boost/static_string/config.hpp>
+#include <algorithm>
+#include <climits>
+#include <cstddef>
+#include <ostream>
+#include <string>
+#include <string_view>
+#include <stdexcept>
+#include <type_traits>
+
+namespace boost {
+namespace static_strings {
+
+namespace detail {
+
+// Primary template: No remaining-capacity trick; uses traits::length() for size.
+template<std::size_t N, typename CharT, typename Traits, bool UseRemaining>
+class static_cstring_base
+{
+public:
+    using traits_type = Traits;
+    using value_type = CharT;
+    using size_type = std::size_t;
+
+    value_type data_[N + 1]{};
+
+    constexpr size_type get_size() const noexcept
+    {
+        return traits_type::length(data_);
+    }
+
+    constexpr void set_size(size_type sz) noexcept
+    {
+        data_[sz] = value_type{};
+    }
+
+    constexpr void init_empty() noexcept
+    {
+        data_[0] = value_type{};
+    }
+
+    // Defaulted comparisons for structural type support.
+    constexpr bool operator==(const static_cstring_base&) const noexcept = default;
+    constexpr auto operator<=>(const static_cstring_base&) const noexcept = default;
+};
+
+// Specialization for N <= UCHAR_MAX: Use remaining-capacity trick.
+template<std::size_t N, typename CharT, typename Traits>
+class static_cstring_base<N, CharT, Traits, true>
+{
+public:
+    using traits_type = Traits;
+    using value_type = CharT;
+    using size_type = std::size_t;
+
+    value_type data_[N + 1]{};
+
+    constexpr size_type get_size() const noexcept
+    {
+        return N - static_cast<unsigned char>(data_[N]);
+    }
+
+    constexpr void set_size(size_type sz) noexcept
+    {
+        data_[sz] = value_type{};
+        data_[N] = static_cast<value_type>(N - sz);
+    }
+
+    constexpr void init_empty() noexcept
+    {
+        data_[0] = value_type{};
+        data_[N] = static_cast<value_type>(N);
+    }
+
+    // Defaulted comparisons for structural type support.
+    constexpr bool operator==(const static_cstring_base&) const noexcept = default;
+    constexpr auto operator<=>(const static_cstring_base&) const noexcept = default;
+};
+
+} // namespace detail
+
+template<std::size_t N, typename CharT = char, typename Traits = std::char_traits<CharT>>
+class basic_static_cstring
+    : public detail::static_cstring_base<N, CharT, Traits, (N <= UCHAR_MAX)>
+{
+public:
+    using base = detail::static_cstring_base<N, CharT, Traits, (N <= UCHAR_MAX)>;
+    using base::data_;
+    using base::get_size;
+    using base::set_size;
+    using base::init_empty;
+
+    // Member types
+    using traits_type     = Traits;
+    using value_type      = CharT;
+    using size_type       = std::size_t;
+    using difference_type = std::ptrdiff_t;
+    using reference       = value_type&;
+    using const_reference = const value_type&;
+    using pointer         = value_type*;
+    using const_pointer   = const value_type*;
+    using iterator        = pointer;
+    using const_iterator  = const_pointer;
+
+    static constexpr size_type npos = static_cast<size_type>(-1);
+    static constexpr size_type static_capacity = N;
+
+    // Constructors.
+    constexpr basic_static_cstring() noexcept
+    {
+        init_empty();
+    }
+
+    constexpr basic_static_cstring(const CharT* s)
+    {
+        assign(s);
+    }
+
+    constexpr basic_static_cstring(const CharT* s, size_type count)
+    {
+        assign(s, count);
+    }
+
+    constexpr basic_static_cstring(size_type count, CharT ch)
+    {
+        assign(count, ch);
+    }
+
+    template<std::size_t M>
+    constexpr basic_static_cstring(const CharT (&arr)[M])
+    {
+        static_assert(M <= N + 1, "String literal too long for static_cstring");
+        assign(arr, M - 1);
+    }
+
+    constexpr size_type size() const noexcept
+    {
+        return get_size();
+    }
+
+    constexpr size_type length() const noexcept
+    {
+        return size();
+    }
+
+    constexpr bool empty() const noexcept
+    {
+        return data_[0] == value_type{};
+    }
+
+    static constexpr size_type max_size() noexcept
+    {
+        return N;
+    }
+
+    static constexpr size_type capacity() noexcept
+    {
+        return N;
+    }
+
+    // Element access.
+    constexpr reference operator[](size_type pos) noexcept
+    {
+        return data_[pos];
+    }
+
+    constexpr const_reference operator[](size_type pos) const noexcept
+    {
+        return data_[pos];
+    }
+
+    constexpr reference at(size_type pos)
+    {
+        if (pos >= size())
+        {
+            throw std::out_of_range("static_cstring::at");
+        }
+        return data_[pos];
+    }
+
+    constexpr const_reference at(size_type pos) const
+    {
+        if (pos >= size())
+        {
+            throw std::out_of_range("static_cstring::at");
+        }
+        return data_[pos];
+    }
+
+    constexpr reference front() noexcept
+    {
+        return data_[0];
+    }
+
+    constexpr const_reference front() const noexcept
+    {
+        return data_[0];
+    }
+
+    constexpr reference back() noexcept
+    {
+        return data_[size() - 1];
+    }
+
+    constexpr const_reference back() const noexcept
+    {
+        return data_[size() - 1];
+    }
+
+    constexpr pointer data() noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_pointer data() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_pointer c_str() const noexcept
+    {
+        return data_;
+    }
+
+    // Iterators.
+    constexpr iterator begin() noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_iterator begin() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_iterator cbegin() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr iterator end() noexcept
+    {
+        return data_ + size();
+    }
+
+    constexpr const_iterator end() const noexcept
+    {
+        return data_ + size();
+    }
+
+    constexpr const_iterator cend() const noexcept
+    {
+        return data_ + size();
+    }
+
+    // Modifiers.
+    constexpr void clear() noexcept
+    {
+        init_empty();
+    }
+
+    constexpr basic_static_cstring& assign(const CharT* s)
+    {
+        return assign(s, traits_type::length(s));
+    }
+
+    constexpr basic_static_cstring& assign(const CharT* s, size_type count)
+    {
+        if (count > N)
+        {
+            throw std::length_error("static_cstring::assign");
+        }
+        traits_type::copy(data_, s, count);
+        set_size(count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& assign(size_type count, CharT ch)
+    {
+        if (count > N)
+        {
+            throw std::length_error("static_cstring::assign");
+        }
+        traits_type::assign(data_, count, ch);
+        set_size(count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& operator=(const CharT* s)
+    {
+        return assign(s);
+    }
+
+    constexpr void push_back(CharT ch)
+    {
+        const size_type sz = size();
+        if (sz >= N)
+        {
+            throw std::length_error("static_cstring::push_back");
+        }
+        data_[sz] = ch;
+        set_size(sz + 1);
+    }
+
+    constexpr void pop_back() noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        set_size(size() - 1);
+    }
+
+    constexpr basic_static_cstring& append(const CharT* s)
+    {
+        return append(s, traits_type::length(s));
+    }
+
+    constexpr basic_static_cstring& append(const CharT* s, size_type count)
+    {
+        const size_type sz = size();
+        if (sz + count > N)
+        {
+            throw std::length_error("static_cstring::append");
+        }
+        traits_type::copy(data_ + sz, s, count);
+        set_size(sz + count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& append(size_type count, CharT ch)
+    {
+        const size_type sz = size();
+        if (sz + count > N)
+        {
+            throw std::length_error("static_cstring::append");
+        }
+        traits_type::assign(data_ + sz, count, ch);
+        set_size(sz + count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& operator+=(const CharT* s)
+    {
+        return append(s);
+    }
+
+    constexpr basic_static_cstring& operator+=(CharT ch)
+    {
+        push_back(ch);
+        return *this;
+    }
+
+    // Comparisons.
+    constexpr int compare(const basic_static_cstring& other) const noexcept
+    {
+        const size_type lhs_sz = size();
+        const size_type rhs_sz = other.size();
+        const int result = traits_type::compare(data_, other.data_, (std::min)(lhs_sz, rhs_sz));
+
+        return result != 0
+                 ? result
+                 : lhs_sz < rhs_sz
+                 ? -1
+                 : lhs_sz > rhs_sz
+                 ? 1
+                 : 0;
+    }
+
+    constexpr int compare(const CharT* s) const noexcept
+    {
+        return compare(basic_static_cstring(s));
+    }
+
+    // Conversions.
+    constexpr operator std::basic_string_view<CharT, Traits>() const noexcept
+    {
+        return {data_, size()};
+    }
+
+    std::basic_string<CharT, Traits> str() const
+    {
+        return {data_, size()};
+    }
+
+    // Swap.
+    constexpr void swap(basic_static_cstring& other) noexcept
+    {
+        basic_static_cstring tmp = *this;
+        *this = other;
+        other = tmp;
+    }
+
+    // Defaulted comparisons for structural type (C++20).
+    constexpr bool operator==(const basic_static_cstring&) const noexcept = default;
+    constexpr auto operator<=>(const basic_static_cstring&) const noexcept = default;
+};
+
+#if defined(BOOST_STATIC_STRING_USE_DEDUCT)
+
+// Deduction guide.
+template<std::size_t N, typename CharT>
+basic_static_cstring(const CharT(&)[N]) -> basic_static_cstring<N - 1, CharT>;
+
+#endif
+
+// Comparison with const CharT*.
+template<std::size_t N, typename CharT, typename Traits>
+constexpr bool operator==(const basic_static_cstring<N, CharT, Traits>& lhs,
+                          const CharT* rhs) noexcept
+{
+    return lhs.compare(rhs) == 0;
+}
+
+template<std::size_t N, typename CharT, typename Traits>
+constexpr bool operator==(const CharT* lhs,
+                          const basic_static_cstring<N, CharT, Traits>& rhs) noexcept
+{
+    return rhs.compare(lhs) == 0;
+}
+
+// Stream output.
+template<std::size_t N, typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os,
+                                              const basic_static_cstring<N, CharT, Traits>& str)
+{
+    return os << str.c_str();
+}
+
+// Alias templates.
+template<std::size_t N>
+using static_cstring = basic_static_cstring<N, char>;
+
+template<std::size_t N>
+using static_wcstring = basic_static_cstring<N, wchar_t>;
+
+}
+}
+
+#endif

example/static_cstring/static_cstring_test.cpp

@@ -0,0 +1,673 @@
+//
+// Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#include "static_cstring.hpp"
+
+#include <boost/core/lightweight_test.hpp>
+#include <climits>
+#include <cstring>
+#include <sstream>
+#include <string>
+#include <string_view>
+#include <type_traits>
+
+namespace boost {
+namespace static_strings {
+
+static
+void
+testCStringSizeGuarantee()
+{
+    // Core guarantee: sizeof is exactly N + 1 (no size member).
+    static_assert(sizeof(static_cstring<0>) == 1, "");
+    static_assert(sizeof(static_cstring<1>) == 2, "");
+    static_assert(sizeof(static_cstring<10>) == 11, "");
+    static_assert(sizeof(static_cstring<63>) == 64, "");
+    static_assert(sizeof(static_cstring<64>) == 65, "");
+    static_assert(sizeof(static_cstring<127>) == 128, "");
+    static_assert(sizeof(static_cstring<UCHAR_MAX>) == (UCHAR_MAX + 1), "");
+    static_assert(sizeof(static_cstring<UCHAR_MAX + 1>) == (UCHAR_MAX + 2), "");
+    static_assert(sizeof(static_cstring<1000>) == 1001, "");
+}
+
+static
+void
+testCStringRemainingCapacityTrick()
+{
+    // Test the remaining-capacity optimization for N <= UCHAR_MAX.
+
+    // Full capacity: Last byte is both null terminator AND remaining == 0.
+    {
+        static_cstring<5> full("12345");
+        BOOST_TEST(full.size() == 5);
+        BOOST_TEST(full.capacity() == 5);
+        BOOST_TEST(full.data()[5] == '\0');
+        BOOST_TEST(std::strcmp(full.c_str(), "12345") == 0);
+    }
+
+    // Partial fill: Null terminator at position size, remaining at position N.
+    {
+        static_cstring<10> partial("Hi");
+        BOOST_TEST(partial.size() == 2);
+        BOOST_TEST(partial.capacity() == 10);
+        BOOST_TEST(partial.data()[2] == '\0');
+        BOOST_TEST(static_cast<unsigned char>(partial.data()[10]) == 8);
+    }
+
+    // Empty string.
+    {
+        static_cstring<10> empty;
+        BOOST_TEST(empty.size() == 0);
+        BOOST_TEST(empty.capacity() == 10);
+        BOOST_TEST(empty.data()[0] == '\0');
+        BOOST_TEST(static_cast<unsigned char>(empty.data()[10]) == 10);
+    }
+
+    // Edge case: N == UCHAR_MAX (max for our trick).
+    {
+        static_cstring<UCHAR_MAX> large;
+        large.assign(100, 'x');
+        BOOST_TEST(large.size() == 100);
+        BOOST_TEST(large.capacity() == UCHAR_MAX);
+        BOOST_TEST(static_cast<unsigned char>(large.data()[UCHAR_MAX]) == (large.capacity() - large.size()));
+    }
+}
+
+static
+void
+testCStringTypeTraits()
+{
+    // static_cstring should be trivially copyable for use in POD structs.
+    {
+        using S = static_cstring<0>;
+        static_assert(std::is_trivially_copyable<S>::value, "");
+        static_assert(std::is_trivially_copy_constructible<S>::value, "");
+        static_assert(std::is_trivially_move_constructible<S>::value, "");
+        static_assert(std::is_trivially_copy_assignable<S>::value, "");
+        static_assert(std::is_trivially_move_assignable<S>::value, "");
+        static_assert(std::is_trivially_destructible<S>::value, "");
+    }
+    {
+        using S = static_cstring<63>;
+        static_assert(std::is_trivially_copyable<S>::value, "");
+        static_assert(std::is_trivially_copy_constructible<S>::value, "");
+        static_assert(std::is_trivially_move_constructible<S>::value, "");
+        static_assert(std::is_trivially_copy_assignable<S>::value, "");
+        static_assert(std::is_trivially_move_assignable<S>::value, "");
+        static_assert(std::is_trivially_destructible<S>::value, "");
+    }
+    {
+        using S = static_cstring<300>;
+        static_assert(std::is_trivially_copyable<S>::value, "");
+        static_assert(std::is_trivially_copy_constructible<S>::value, "");
+        static_assert(std::is_trivially_move_constructible<S>::value, "");
+        static_assert(std::is_trivially_copy_assignable<S>::value, "");
+        static_assert(std::is_trivially_move_assignable<S>::value, "");
+        static_assert(std::is_trivially_destructible<S>::value, "");
+    }
+}
+
+static
+void
+testCStringConstruct()
+{
+    // Default construction.
+    {
+        static_cstring<1> s;
+        BOOST_TEST(s.empty());
+        BOOST_TEST(s.size() == 0);
+        BOOST_TEST(s == "");
+        BOOST_TEST(*s.end() == 0);
+    }
+
+    // Construct with count and char.
+    {
+        static_cstring<4> s1(3, 'x');
+        BOOST_TEST(!s1.empty());
+        BOOST_TEST(s1.size() == 3);
+        BOOST_TEST(s1 == "xxx");
+        BOOST_TEST(*s1.end() == 0);
+        BOOST_TEST_THROWS(
+            (static_cstring<2>(3, 'x')),
+            std::length_error);
+    }
+
+    // Construct from a C string.
+    {
+        static_cstring<5> s1("12345");
+        BOOST_TEST(s1.size() == 5);
+        BOOST_TEST(s1 == "12345");
+        BOOST_TEST(*s1.end() == 0);
+        BOOST_TEST_THROWS(
+            (static_cstring<4>("12345")),
+            std::length_error);
+    }
+
+    // Construct from a C string with count.
+    {
+        static_cstring<5> s1("UVXYZ", 3);
+        BOOST_TEST(s1 == "UVX");
+        BOOST_TEST(*s1.end() == 0);
+    }
+
+    // Copy construction.
+    {
+        static_cstring<5> s1("12345");
+        static_cstring<5> s2(s1);
+        BOOST_TEST(s2 == "12345");
+        BOOST_TEST(*s2.end() == 0);
+    }
+}
+
+static
+void
+testCStringAssignment()
+{
+    // assign(size_type count, CharT ch).
+    BOOST_TEST(static_cstring<3>{}.assign(1, '*') == "*");
+    BOOST_TEST(static_cstring<3>{}.assign(3, '*') == "***");
+    BOOST_TEST(static_cstring<3>{"abc"}.assign(3, '*') == "***");
+    BOOST_TEST_THROWS(static_cstring<1>{"a"}.assign(2, '*'), std::length_error);
+
+    // assign(CharT const* s, size_type count).
+    BOOST_TEST(static_cstring<3>{}.assign("abc", 3) == "abc");
+    BOOST_TEST(static_cstring<3>{"*"}.assign("abc", 3) == "abc");
+    BOOST_TEST_THROWS(static_cstring<1>{}.assign("abc", 3), std::length_error);
+
+    // assign(CharT const* s).
+    BOOST_TEST(static_cstring<3>{}.assign("abc") == "abc");
+    BOOST_TEST(static_cstring<3>{"*"}.assign("abc") == "abc");
+    BOOST_TEST_THROWS(static_cstring<1>{}.assign("abc"), std::length_error);
+
+    // operator=(const CharT* s).
+    {
+        static_cstring<3> s1;
+        s1 = "123";
+        BOOST_TEST(s1 == "123");
+        BOOST_TEST(*s1.end() == 0);
+        static_cstring<1> s2;
+        BOOST_TEST_THROWS(
+            s2 = "123",
+            std::length_error);
+    }
+
+    // Copy assignment.
+    {
+        static_cstring<3> s1("123");
+        static_cstring<3> s2;
+        s2 = s1;
+        BOOST_TEST(s2 == "123");
+        BOOST_TEST(*s2.end() == 0);
+    }
+}
+
+static
+void
+testCStringElements()
+{
+    using ccs3 = static_cstring<3> const;
+
+    // at(size_type pos).
+    BOOST_TEST(static_cstring<3>{"abc"}.at(0) == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}.at(2) == 'c');
+    BOOST_TEST_THROWS(static_cstring<3>{""}.at(0), std::out_of_range);
+    BOOST_TEST_THROWS(static_cstring<3>{"abc"}.at(4), std::out_of_range);
+
+    // at(size_type pos) const.
+    BOOST_TEST(ccs3{"abc"}.at(0) == 'a');
+    BOOST_TEST(ccs3{"abc"}.at(2) == 'c');
+    BOOST_TEST_THROWS(ccs3{""}.at(0), std::out_of_range);
+
+    // operator[](size_type pos).
+    BOOST_TEST(static_cstring<3>{"abc"}[0] == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}[2] == 'c');
+    BOOST_TEST(static_cstring<3>{"abc"}[3] == 0);
+    BOOST_TEST(static_cstring<3>{""}[0] == 0);
+
+    // front() / back().
+    BOOST_TEST(static_cstring<3>{"abc"}.front() == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}.back() == 'c');
+
+    // data() / c_str().
+    {
+        static_cstring<3> s("123");
+        BOOST_TEST(std::memcmp(s.data(), "123", 3) == 0);
+        BOOST_TEST(std::memcmp(s.c_str(), "123\0", 4) == 0);
+    }
+
+    // Modification through element access.
+    {
+        static_cstring<5> s("12345");
+        s[1] = '_';
+        BOOST_TEST(s == "1_345");
+        s.front() = 'A';
+        BOOST_TEST(s == "A_345");
+        s.back() = 'Z';
+        BOOST_TEST(s == "A_34Z");
+    }
+}
+
+static
+void
+testCStringIterators()
+{
+    {
+        static_cstring<3> s;
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 0);
+        s = "123";
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 3);
+    }
+    {
+        static_cstring<3> const s("123");
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 3);
+        BOOST_TEST(std::distance(s.cbegin(), s.cend()) == 3);
+    }
+
+    // Iteration.
+    {
+        static_cstring<5> s("hello");
+        std::string result;
+        for (const char c : s)
+        {
+            result += c;
+        }
+        BOOST_TEST(result == "hello");
+    }
+}
+
+static
+void
+testCStringCapacity()
+{
+    // empty().
+    BOOST_TEST(static_cstring<0>{}.empty());
+    BOOST_TEST(static_cstring<1>{}.empty());
+    BOOST_TEST(!static_cstring<1>{"a"}.empty());
+
+    // size().
+    BOOST_TEST(static_cstring<0>{}.size() == 0);
+    BOOST_TEST(static_cstring<1>{"a"}.size() == 1);
+    BOOST_TEST(static_cstring<5>{"abc"}.size() == 3);
+
+    // length().
+    BOOST_TEST(static_cstring<0>{}.length() == 0);
+    BOOST_TEST(static_cstring<3>{"abc"}.length() == 3);
+
+    // max_size().
+    BOOST_TEST(static_cstring<0>{}.max_size() == 0);
+    BOOST_TEST(static_cstring<5>{"abc"}.max_size() == 5);
+
+    // capacity().
+    BOOST_TEST(static_cstring<0>{}.capacity() == 0);
+    BOOST_TEST(static_cstring<5>{"abc"}.capacity() == 5);
+}
+
+static
+void
+testCStringClear()
+{
+    static_cstring<3> s("123");
+    BOOST_TEST(!s.empty());
+    s.clear();
+    BOOST_TEST(s.empty());
+    BOOST_TEST(s.size() == 0);
+    BOOST_TEST(*s.end() == 0);
+    BOOST_TEST(s == "");
+}
+
+static
+void
+testCStringPushPop()
+{
+    // push_back().
+    {
+        static_cstring<5> s("abc");
+        s.push_back('d');
+        BOOST_TEST(s == "abcd");
+        BOOST_TEST(s.size() == 4);
+        BOOST_TEST(*s.end() == 0);
+
+        s.push_back('e');
+        BOOST_TEST(s == "abcde");
+        BOOST_TEST(s.size() == 5);
+
+        BOOST_TEST_THROWS(s.push_back('f'), std::length_error);
+    }
+
+    // pop_back().
+    {
+        static_cstring<5> s("abcde");
+        s.pop_back();
+        BOOST_TEST(s == "abcd");
+        BOOST_TEST(s.size() == 4);
+        BOOST_TEST(*s.end() == 0);
+
+        s.pop_back();
+        s.pop_back();
+        s.pop_back();
+        s.pop_back();
+        BOOST_TEST(s.empty());
+    }
+}
+
+static
+void
+testCStringAppend()
+{
+    // append(const CharT* s).
+    {
+        static_cstring<12> s("Hello");
+        s.append(", World");
+        BOOST_TEST(s == "Hello, World");
+        BOOST_TEST(*s.end() == 0);
+    }
+    {
+        static_cstring<5> s("abc");
+        BOOST_TEST_THROWS(s.append("def"), std::length_error);
+    }
+
+    // append(const CharT* s, size_type count)
+    {
+        static_cstring<10> s("abc");
+        s.append("defgh", 3);
+        BOOST_TEST(s == "abcdef");
+        BOOST_TEST(*s.end() == 0);
+    }
+
+    // append(size_type count, CharT ch)
+    {
+        static_cstring<10> s("abc");
+        s.append(3, 'x');
+        BOOST_TEST(s == "abcxxx");
+        BOOST_TEST(*s.end() == 0);
+        BOOST_TEST_THROWS(s.append(5, 'y'), std::length_error);
+    }
+
+    // operator+=()
+    {
+        static_cstring<10> s("abc");
+        s += "def";
+        BOOST_TEST(s == "abcdef");
+        s += 'g';
+        BOOST_TEST(s == "abcdefg");
+        BOOST_TEST(*s.end() == 0);
+    }
+}
+
+static
+void
+testCStringComparison()
+{
+    // operator==() / operator!=().
+    {
+        static_cstring<10> a("abc");
+        static_cstring<10> b("abc");
+        static_cstring<10> c("abd");
+
+        BOOST_TEST(a == b);
+        BOOST_TEST(!(a == c));
+        BOOST_TEST(a != c);
+        BOOST_TEST(!(a != b));
+    }
+
+    // operator<(), <=(), >(), >=().
+    {
+        static_cstring<10> a("abc");
+        static_cstring<10> b("abd");
+
+        BOOST_TEST(a < b);
+        BOOST_TEST(a <= b);
+        BOOST_TEST(a <= a);
+        BOOST_TEST(b > a);
+        BOOST_TEST(b >= a);
+        BOOST_TEST(b >= b);
+    }
+
+    // Comparison with CharT const*.
+    {
+        static_cstring<10> s("hello");
+        BOOST_TEST(s == "hello");
+        BOOST_TEST("hello" == s);
+        BOOST_TEST(s != "world");
+        BOOST_TEST("world" != s);
+    }
+
+    // compare().
+    {
+        static_cstring<10> s("abc");
+        BOOST_TEST(s.compare("abc") == 0);
+        BOOST_TEST(s.compare("abd") < 0);
+        BOOST_TEST(s.compare("abb") > 0);
+    }
+}
+
+static
+void
+testCStringConversion()
+{
+    // operator string_view().
+    {
+        static_cstring<10> s("hello");
+        std::string_view sv = s;
+        BOOST_TEST(sv == "hello");
+        BOOST_TEST(sv.size() == 5);
+    }
+
+    // str().
+    {
+        static_cstring<10> s("hello");
+        std::string str = s.str();
+        BOOST_TEST(str == "hello");
+        BOOST_TEST(str.size() == 5);
+    }
+}
+
+static
+void
+testCStringStream()
+{
+    static_cstring<10> s("hello");
+    std::ostringstream oss;
+    oss << s;
+    BOOST_TEST(oss.str() == "hello");
+}
+
+static
+void
+testCStringSwap()
+{
+    static_cstring<10> a("hello");
+    static_cstring<10> b("world");
+
+    a.swap(b);
+
+    BOOST_TEST(a == "world");
+    BOOST_TEST(b == "hello");
+}
+
+static
+void
+testCStringConstexpr()
+{
+    // constexpr construction and operations.
+    constexpr static_cstring<10> ce("test");
+    static_assert(ce.size() == 4, "");
+    static_assert(ce[0] == 't', "");
+    static_assert(ce[1] == 'e', "");
+    static_assert(ce[2] == 's', "");
+    static_assert(ce[3] == 't', "");
+    static_assert(!ce.empty(), "");
+    static_assert(ce.max_size() == 10, "");
+    static_assert(ce.capacity() == 10, "");
+
+    constexpr static_cstring<5> ce_empty;
+    static_assert(ce_empty.empty(), "");
+    static_assert(ce_empty.size() == 0, "");
+}
+
+// Helper struct to test NTTP.
+template<basic_static_cstring S>
+struct NTTPHelper
+{
+    static constexpr std::size_t size() noexcept
+    {
+        return S.size();
+    }
+
+    static constexpr const char* c_str() noexcept
+    {
+        return S.c_str();
+    }
+};
+
+static
+void
+testCStringNTTP()
+{
+    // Test non-type template parameter usage (C++20).
+
+    // Test size deduction from string literals.
+    BOOST_TEST(NTTPHelper<"hello">::size() == 5);
+    BOOST_TEST(NTTPHelper<"">::size() == 0);
+    BOOST_TEST(NTTPHelper<"test">::size() == 4);
+
+    // Test that different strings create different types
+    constexpr bool same_type = std::is_same_v<
+        NTTPHelper<"hello">,
+        NTTPHelper<"hello">>;
+    BOOST_TEST(same_type);
+
+    constexpr bool different_type = !std::is_same_v<
+        NTTPHelper<"hello">,
+        NTTPHelper<"world">>;
+    BOOST_TEST(different_type);
+
+    // Test constexpr access.
+    constexpr std::size_t len = NTTPHelper<"constexpr">::size();
+    static_assert(len == 9, "");
+}
+
+static
+void
+testCStringPODUsage()
+{
+    // Test usage in POD types (the original motivation).
+    struct UserRecord
+    {
+        int id;
+        static_cstring<63> name;
+        unsigned int flags;
+    };
+
+    static_assert(sizeof(static_cstring<63>) == 64, "");
+    static_assert(std::is_trivially_copyable<UserRecord>::value, "");
+
+    UserRecord user{};
+    user.id = 42;
+    user.name = "Alice";
+    user.flags = 0xFF;
+
+    BOOST_TEST(user.id == 42);
+    BOOST_TEST(user.name.size() == 5);
+    BOOST_TEST(user.name == "Alice");
+    BOOST_TEST(user.flags == 0xFF);
+
+    // Copy the struct.
+    UserRecord copy = user;
+    BOOST_TEST(copy.name == "Alice");
+
+    // memcpy() should work.
+    UserRecord memcpy_dest;
+    std::memcpy(&memcpy_dest, &user, sizeof(UserRecord));
+    BOOST_TEST(memcpy_dest.name == "Alice");
+}
+
+static
+void
+testCStringLargeCapacity()
+{
+    // Test strings with N > UCHAR_MAX (no remaining-capacity trick).
+    {
+        static_cstring<300> s;
+        BOOST_TEST(s.empty());
+        BOOST_TEST(s.size() == 0);
+
+        s = "This is a test string";
+        BOOST_TEST(s.size() == 21);
+        BOOST_TEST(s == "This is a test string");
+
+        s.clear();
+        BOOST_TEST(s.empty());
+    }
+
+    // Large string operations.
+    {
+        static_cstring<500> s;
+        s.assign(400, 'x');
+        BOOST_TEST(s.size() == 400);
+        BOOST_TEST(s[0] == 'x');
+        BOOST_TEST(s[399] == 'x');
+        BOOST_TEST(*s.end() == 0);
+    }
+}
+
+static
+void
+testCStringWideChar()
+{
+    // Test with wchar_t.
+    {
+        static_wcstring<10> ws;
+        BOOST_TEST(ws.empty());
+        BOOST_TEST(ws.size() == 0);
+    }
+
+    {
+        static_wcstring<10> ws(L"hello");
+        BOOST_TEST(ws.size() == 5);
+        BOOST_TEST(ws[0] == L'h');
+        BOOST_TEST(ws[4] == L'o');
+        BOOST_TEST(*ws.end() == 0);
+    }
+}
+
+int
+runTests()
+{
+  testCStringSizeGuarantee();
+  testCStringRemainingCapacityTrick();
+  testCStringTypeTraits();
+  testCStringConstruct();
+  testCStringAssignment();
+  testCStringElements();
+  testCStringIterators();
+  testCStringCapacity();
+  testCStringClear();
+  testCStringPushPop();
+  testCStringAppend();
+  testCStringComparison();
+  testCStringConversion();
+  testCStringStream();
+  testCStringSwap();
+  testCStringConstexpr();
+  testCStringNTTP();
+  testCStringPODUsage();
+  testCStringLargeCapacity();
+  testCStringWideChar();
+
+  return report_errors();
+}
+}
+}
+
+int
+main()
+{
+  return boost::static_strings::runTests();
+}

include/boost/static_string/config.hpp

@@ -14,6 +14,17 @@
 // Are we dependent on Boost?
 // #define BOOST_STATIC_STRING_STANDALONE
 
+#include <cstdint>
+
+// detect 32/64 bit
+#if UINTPTR_MAX == UINT64_MAX
+#define BOOST_STATIC_STRING_ARCH 64
+#elif UINTPTR_MAX == UINT32_MAX
+#define BOOST_STATIC_STRING_ARCH 32
+#else
+#error Unknown or unsupported architecture, please open an issue
+#endif
+
 // Can we have deduction guides?
 #if __cpp_deduction_guides >= 201703L
 #define BOOST_STATIC_STRING_USE_DEDUCT
@@ -128,9 +139,6 @@
 #ifndef BOOST_STATIC_STRING_THROW
 #define BOOST_STATIC_STRING_THROW(ex) BOOST_THROW_EXCEPTION(ex)
 #endif
-#ifndef BOOST_STATIC_STRING_STATIC_ASSERT
-#define BOOST_STATIC_STRING_STATIC_ASSERT(cond, msg) BOOST_STATIC_ASSERT_MSG(cond, msg)
-#endif
 #ifndef BOOST_STATIC_STRING_ASSERT
 #define BOOST_STATIC_STRING_ASSERT(cond) BOOST_ASSERT(cond)
 #endif
@@ -138,24 +146,60 @@
 #ifndef BOOST_STATIC_STRING_THROW
 #define BOOST_STATIC_STRING_THROW(ex) throw ex
 #endif
-#ifndef BOOST_STATIC_STRING_STATIC_ASSERT
-#define BOOST_STATIC_STRING_STATIC_ASSERT(cond, msg) static_assert(cond, msg)
-#endif
 #ifndef BOOST_STATIC_STRING_ASSERT
 #define BOOST_STATIC_STRING_ASSERT(cond) assert(cond)
 #endif
 #endif
 
 #ifndef BOOST_STATIC_STRING_STANDALONE
+#include <boost/config.hpp>
 #include <boost/assert.hpp>
 #include <boost/container_hash/hash.hpp>
-#include <boost/static_assert.hpp>
 #include <boost/utility/string_view.hpp>
+#include <boost/core/detail/string_view.hpp>
 #include <boost/throw_exception.hpp>
+
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW) || \
+     defined(BOOST_STATIC_STRING_CXX17_STRING_VIEW)
+#include <string_view>
+#define BOOST_STATIC_STRING_HAS_STD_STRING_VIEW
+#endif
 #else
 #include <cassert>
 #include <stdexcept>
+
+#if defined(__has_include)
+#  if !__has_include(<string_view>)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
+/*
+ * Replicate the logic from Boost.Config
+ */
+// GNU libstdc++3:
+#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
+#  if ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 70100) || (__cplusplus <= 201402L)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
+// libc++:
+#elif defined(_LIBCPP_VERSION)
+#  if (_LIBCPP_VERSION < 4000) || (__cplusplus <= 201402L)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
+// MSVC uses logic from catch all for BOOST_NO_CXX17_HDR_STRING_VIEW
+// catch all:
+#elif !defined(_YVALS) && !defined(_CPPLIB_VER)
+#  if (!defined(__has_include) || (__cplusplus < 201700))
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  elif !__has_include(<string_view>)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
+#endif
+
+#if !defined(BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW) || \
+     defined(BOOST_STATIC_STRING_CXX17_STRING_VIEW)
 #include <string_view>
+#define BOOST_STATIC_STRING_HAS_STD_STRING_VIEW
+#endif
 #endif
 
 // Compiler bug prevents constexpr from working with clang 4.x and 5.x
@@ -192,6 +236,30 @@ defined(BOOST_STATIC_STRING_CPP14)
 #define BOOST_STATIC_STRING_GCC5_BAD_CONSTEXPR
 #endif
 
+#ifndef BOOST_STATIC_STRING_STANDALONE
+#if ! defined(BOOST_NO_CWCHAR) && ! defined(BOOST_NO_SWPRINTF)
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#endif
+#else
+#ifndef __has_include
+// If we don't have __has_include in standalone,
+// we will assume that <cwchar> exists.
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#elif __has_include(<cwchar>)
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#endif
+#endif
+
+#ifdef BOOST_STATIC_STRING_HAS_WCHAR
+#include <cwchar>
+#endif
+
+// Define the basic string_view type used by the library
+// Conversions to and from other available string_view types
+// are still defined.
+#if !defined(BOOST_STATIC_STRING_STANDALONE) || \
+     defined(BOOST_STATIC_STRING_HAS_STD_STRING_VIEW)
+#define BOOST_STATIC_STRING_HAS_ANY_STRING_VIEW
 namespace boost {
 namespace static_strings {
 
@@ -205,4 +273,27 @@ using basic_string_view =
 #endif
 } // static_strings
 } // boost
-#endif
+#endif
+
+#if defined(__cpp_lib_to_string) && __cpp_lib_to_string >= 202306L // std::to_[w]string() redefined in terms of std::format()
+#define BOOST_STATIC_STRING_USE_STD_FORMAT
+#endif
+
+#if defined(__GNUC__) && (__GNUC__ >= 5) && (__GNUC__ <= 10) && !defined(__clang__)
+// Workaround for GCC complaining about nested classes being private.
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND public:
+#else
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND
+#endif
+
+// GCC 9 incorrectly rejects the pointer equality comparison in
+// ptr_in_range() in constant expressions. GCC 10 and later handle
+// it correctly.
+//
+// Clang 3.7 and 9-19 have the same issue.
+#if (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ == 9)) \
+    || (defined(__clang__) && ((__clang_major__ == 3 && __clang_minor__ == 7) || ((__clang_major__ >= 9) && (__clang_major__ <= 19))))
+#define BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN
+#endif
+
+#endif

meta/libraries.json

@@ -7,12 +7,13 @@
     ],
     "description": "A fixed capacity dynamically sized string.",
     "category": [
-        "Container",
+        "Containers",
         "String"
     ],
     "maintainers": [
-        "Krystian Stasiowski <sdkrystian@gmail.com>",
-        "Vinnie Falco <vinnie.falco@gmail.com>"
+        "Alan de Freitas <alandefreitas@gmail.com>",
+        "Vinnie Falco <vinnie.falco@gmail.com>",
+        "Gennaro Prota <gennaro.prota@gmail.com>"
     ],
     "cxxstd": "11"
 }

test/CMakeLists.txt

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+# Copyright (c) 2022 Alan de Freitas (alandefreitas@gmail.com)
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -7,16 +7,26 @@
 # Official repository: https://github.com/boostorg/static_string
 #
 
-GroupSources (include/boost/static_string static_string)
-GroupSources (test "/")
+# Custom target used by the boost super-project
+if(NOT TARGET tests)
+        add_custom_target(tests)
+        set_property(TARGET tests PROPERTY FOLDER _deps)
+endif()
 
-add_executable (tests
-    ${PROJECT_FILES}
-    Jamfile
-    static_string.cpp
-)
+set(BOOST_STATIC_STRING_TESTS_FILES
+        CMakeLists.txt
+        Jamfile
+        constexpr_tests.hpp
+        compile_fail.hpp
+        static_string.cpp
+        )
 
-target_link_libraries(tests
-    )
+source_group(TREE ${CMAKE_CURRENT_SOURCE_DIR} FILES ${BOOST_STATIC_STRING_TESTS_FILES})
+add_executable(boost_static_string_tests ${BOOST_STATIC_STRING_TESTS_FILES})
 
-set_property(TARGET tests PROPERTY FOLDER "tests")
+# The include dependencies are found in the CMakeLists.txt
+# of the root project directory.
+# See: BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES
+target_link_libraries(boost_static_string_tests PRIVATE Boost::static_string)
+add_test(NAME boost_static_string_tests COMMAND boost_static_string_tests)
+add_dependencies(tests boost_static_string_tests)

test/Jamfile

@@ -8,18 +8,21 @@
 #
 
 import testing ;
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 
 local defines =
     [ requires
     cxx11_constexpr
     cxx11_decltype
     cxx11_hdr_tuple
+    cxx11_hdr_type_traits
     cxx11_template_aliases
     cxx11_variadic_templates
     ]
     ;
 
-project : requirements $(defines) ;
+project : requirements $(defines)
+    <library>/boost/static_string//boost_static_string ;
 
 run static_string.cpp ;

test/cmake_test/CMakeLists.txt

@@ -0,0 +1,24 @@
+# Copyright 2021-2025 Alexander Grund
+# 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
+
+cmake_minimum_required(VERSION 3.8...3.16)
+
+project(cmake_subdir_test LANGUAGES CXX)
+
+# Those 2 should work the same
+# while using find_package for the installed Boost avoids the need to manually specify dependencies
+if(BOOST_CI_INSTALL_TEST)
+    find_package(boost_static_string REQUIRED)
+else()
+    set(BOOST_INCLUDE_LIBRARIES static_string)
+    add_subdirectory(../../../.. deps/boost EXCLUDE_FROM_ALL)
+endif()
+
+add_executable(main main.cpp)
+target_link_libraries(main Boost::static_string)
+
+enable_testing()
+add_test(NAME main COMMAND main)
+
+add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/cmake_test/main.cpp

@@ -0,0 +1,18 @@
+//
+// Copyright (c) 2025 Alexander Grund
+//
+// 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)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#include <boost/static_string.hpp>
+
+int main()
+{
+    // Smoke test only
+    boost::static_string<1> s_empty;
+    boost::static_string<4> s_3(3, 'x');
+    return (s_empty.empty() && s_3.size() == 3) ? 0 : 1;
+}

test/compile_fail.hpp

@@ -4,16 +4,6 @@
 namespace boost {
 namespace static_strings {
 
-static_assert(std::is_base_of<
-  detail::static_string_base<0, char, std::char_traits<char>>,
-              static_string<0>>::value,
-              "the zero size optimization shall be used for N = 0");
-
-static_assert(std::is_base_of<
-  detail::static_string_base<(std::numeric_limits<char>::max)() + 1, char, std::char_traits<char>>,
-              static_string<(std::numeric_limits<char>::max)() + 1>>::value,
-              "the minimum size type optimization shall be used for N > 0");
-
 static_assert(!detail::is_input_iterator<int>::value, "is_input_iterator is incorrect");
 static_assert(!detail::is_input_iterator<double>::value, "is_input_iterator is incorrect");
 static_assert(detail::is_input_iterator<int*>::value, "is_input_iterator is incorrect");

test/constexpr_tests.hpp

@@ -22,38 +22,78 @@ struct cxper_char_traits
   using int_type = int;
   using state_type = std::mbstate_t;
 
-  static constexpr void assign(char_type& a, const char_type& b) noexcept { a = b;  }
-  static constexpr bool eq(char_type a, char_type b) noexcept { return a == b; }
-  static constexpr bool lt(char_type a, char_type b) noexcept { return a < b; }
+  static constexpr void assign(char_type& a, const char_type& b) noexcept
+  {
+    a = b;
+  }
+
+  static constexpr bool eq(char_type a, char_type b) noexcept
+  {
+    return a == b;
+  }
+
+  static constexpr bool lt(char_type a, char_type b) noexcept
+  {
+    return a < b;
+  }
+
+  static constexpr int compare(const char_type* a, const char_type* b, std::size_t n)
+  {
+    for (; n--; ++a, ++b)
+    {
+      if(lt(*a, *b))
+        return 1;
+      else if(lt(*b, *a))
+        return -1;
+    }
+    return 0;
+  }
 
-  static constexpr int compare(const char_type*, const char_type*, std::size_t) { return 0; }
   static constexpr std::size_t length(const char_type* s)
   {
-    std::size_t n = 0;
-    while (*(s++));
-    return n;
+    auto ptr = s;
+    while (!eq(*ptr, char_type()))
+      ++ptr;
+    return ptr - s;
   }
-  static constexpr const char_type* find(const char_type*, std::size_t, const char_type&){ return 0; }
+
+  static constexpr const char_type* find(const char_type* s, std::size_t n, const char_type& ch)
+  {
+    for (; n--; ++s)
+    {
+      if (eq(*s, ch))
+        return s;
+    }
+    return nullptr;
+  }
+
   static constexpr char_type* move(char_type* dest, const char_type* src, std::size_t n)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = *(src++);
-    return temp;
+    // This implementation does not handle overlapping ranges where
+    // dest > src. A correct implementation would need to detect this
+    // case and copy backwards, but detecting overlap requires pointer
+    // comparisons that are not allowed in constant expressions when
+    // the pointers point to unrelated objects (e.g., a string literal
+    // and the static_string's internal buffer).
+    //
+    // Since cxper_char_traits is only used for testing constexpr
+    // functionality and the tests do not exercise overlapping moves
+    // where dest > src, this simple forward copy is sufficient.
+    return copy(dest, src, n);
   }
+
   static constexpr char_type* copy(char_type* dest, const char_type* src, std::size_t n)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = *(src++);
-    return temp;
+    for (auto ptr = dest; n--;)
+      assign(*ptr++, *src++);
+    return dest;
   }
+
   static constexpr char_type* assign(char_type* dest, std::size_t n, char_type ch)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = ch;
-    return temp;
+    for (auto ptr = dest; n--;)
+      assign(*ptr++, ch);
+    return dest;
   }
 };
 #else
@@ -67,6 +107,23 @@ bool
 testConstantEvaluation()
 {
 #ifdef BOOST_STATIC_STRING_CPP20
+
+  // Check construction in a constexpr context
+  constexpr basic_static_string s("hello");
+  static_assert(s.size() == 5);
+  static_assert(s.static_capacity == 5);
+  static_assert(s == "hello");
+
+  // Check assignment in a constexpr context
+  constexpr auto s2 =
+  []()
+  {
+    basic_static_string s("hello");
+    s = "world";
+    return s;
+  }();
+  static_assert(s2 == "world");
+
   // c++20 constexpr tests
   cstatic_string a;
   cstatic_string b(1, 'a');
@@ -171,8 +228,10 @@ testConstantEvaluation()
 
   a.substr(0);
 
+#ifdef BOOST_STATIC_STRING_HAS_ANY_STRING_VIEW
   // subview
   a.subview(0);
+#endif
 
   // copy
   char k[20]{};
@@ -198,7 +257,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -357,8 +417,10 @@ testConstantEvaluation()
   a.substr(0);
 #endif
 
+#ifdef BOOST_STATIC_STRING_HAS_STRING_VIEW
   // subview
   a.subview(0);
+#endif
 
   // copy
   char k[20]{};
@@ -384,7 +446,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -556,7 +619,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -603,5 +667,28 @@ testConstantEvaluation()
     cstatic_string().empty();
 #endif
 }
+
+#if __cpp_nontype_template_args >= 201911L
+
+template<basic_static_string<32, char, cxper_char_traits> X>
+struct nttp_primary
+{
+  static constexpr bool value = false;
+};
+
+template<>
+struct nttp_primary<"test string">
+{
+  static constexpr bool value = true;
+};
+
+static_assert(!nttp_primary<"random string">::value,
+  "structural equality broken");
+
+static_assert(nttp_primary<"test string">::value,
+  "structural equality broken");
+
+#endif
+
 } // static_strings
-} // boost
+} // boost